Citation Nr: 23016080 Decision Date: 03/16/23 Archive Date: 03/16/23 DOCKET NO. 18-31 488 DATE: March 16, 2023 ORDER Service connection for gastroesophageal reflux disease (GERD) (an esophageal condition), on a direct basis and on a presumptive basis, due to exposure to contaminated water at Camp Lejeune and as a qualifying chronic disability under 38 C.F.R. § 3.317, is denied. Service connection for gastritis (a stomach or duodenal condition), on a direct basis and on a presumptive basis, due to exposure to contaminated water at Camp Lejeune and as a qualifying chronic disability under 38 C.F.R. § 3.317, is denied. Service connection for posttraumatic stress disorder (PTSD) based on personal assaults / a pattern of harassment is granted. Service connection for major depressive disorder with associated anxiety, insomnia, and memory loss is granted. Service connection for a bowel disturbance with abdominal distress (an intestinal condition) as a qualifying chronic disability under 38 C.F.R. § 3.317 is granted. Service connection for type II diabetes mellitus as a qualifying chronic disability under 38 C.F.R. § 3.317 is granted. Service connection for hyperlipidemia (high cholesterol) with angina (chest pain) is granted. Service connection for hypertension as secondary to now service-connected hyperlipidemia (high cholesterol) with angina (chest pain) is granted. Service connection for diabetic peripheral neuropathy of the RIGHT lower extremity as secondary to now service-connected type II diabetes mellitus is granted. Service connection for diabetic peripheral neuropathy of the LEFT lower extremity as secondary to now service-connected type II diabetes mellitus is granted. Service connection for an alcohol abuse disorder and polysubstance abuse disorder as secondary to now service-connected PTSD and major depressive disorder is granted. A higher initial 20 percent rating, but no greater, for a lumbosacral strain is granted. From August 26, 2013 to the present, a higher initial 50 percent rating, but no greater, for tension headaches is granted. REMANDED Service connection for a LEFT shoulder disorder is remanded. Service connection for gastroesophageal reflux disease (GERD) (an esophageal condition) on a secondary basis to service-connected PTSD, major depressive disorder, alcohol and polysubstance abuse disorders, and tension headaches is remanded. Service connection for gastritis (a stomach or duodenal condition) on a secondary basis to service-connected PTSD, major depressive disorder, alcohol and polysubstance abuse disorders, and tension headaches is remanded. Entitlement to a total disability rating based on individual unemployability (TDIU) due to service-connected disabilities is remanded. FINDINGS OF FACT 1. The Veteran may have served at the Camp Lejeune Marine Corps Base in North Carolina in 1988, and if so, he is presumed exposed to contaminated water while serving at this facility. 2. The Veteran's GERD and gastritis are not listed as presumptive diseases associated with exposure to contaminants in the water supply at Camp Lejeune. 3. The Veteran served in the Southwest Asia Theater of Operations during the Persian Gulf War in 1990 and 1991. 4. The Veteran's GERD and gastritis are not qualifying chronic disabilities resulting from an undiagnosed illness or from a medically unexplained chronic multisymptom illness (MUCMI) without conclusive pathophysiology or etiology. 5. The Veteran's current GERD and gastritis are not directly related to any presumed exposure to contaminated water at Camp Lejeune during active service or to his presumed exposure to Persian Gulf chemical and environmental hazards in Southwest Asia during active service. And neither disease was otherwise incurred during his period of active service. 6. There is credible evidence for the occurrence of the Veteran's alleged in-service personal assaults / a pattern of harassment by drill instructors while serving in the U.S. Marine Corps from August 1988 to August 1992 (e.g., in-service behavioral changes and substance abuse). 7. The evidence of record is "approximately" balanced on whether the Veteran has a current diagnosis of PTSD (per the DSM-5) as the result of the physical assaults / pattern of harassment that occurred during his period of active duty with the U.S. Marine Corps from August 1988 to August 1992. 8. The evidence of record is "approximately" balanced on whether the onset of the Veteran's major depressive disorder with associated anxiety, insomnia, and memory loss was during active service in the U.S. Marine Corps from 1988 to 1992, after experiencing various traumatic incidents and engaging in in-service alcohol abuse. 9. The Veteran's bowel disturbance with abdominal distress (an intestinal condition) is a qualifying chronic disability resulting from an undiagnosed illness, presumed due to his Persian Gulf service. This disability can at least be rated as compensable (10 percent disabling or more). 10. The Veteran's type II diabetes mellitus is a qualifying chronic disability resulting from a diagnosable, but medically unexplained multi-symptom illness without conclusive etiology, presumed due to his Persian Gulf service. This disability can at least be rated as compensable. 11. Hyperlipidemia (high cholesterol) with angina (chest pain), although not specifically listed as a disability in VA's rating schedule, nevertheless results in "functional impairment of earning capacity" for this Veteran. Moreover, the Veteran's hyperlipidemia (high cholesterol) with angina (chest pain) first manifested during his period of service with the Marine Corps from 1988 to 1992. 12. The Veteran's current hypertension is proximately due to or the result of his now service-connected hyperlipidemia (high cholesterol) with angina (chest pain). 13. The Veteran has current diabetic peripheral neuropathy in both lower extremities proximately due to, the result of, or a complication of his now service-connected type II diabetes mellitus. 14. The Veteran has current alcohol abuse and polysubstance abuse disorders proximately due to or a component of his now service-connected PTSD and major depressive disorder. 15. The Veteran's service-connected lumbosacral strain causes muscle spasms severe enough to result in an abnormal gait at times, in the absence of the various pain medications he must take on a daily basis for his lumbar spine. However, even when considering the factors of functional loss during flare-ups or after repetitive motion, his lumbosacral strain disability is not productive of unfavorable ankylosis of the entire spine, unfavorable ankylosis of the entire thoracolumbar spine, favorable ankylosis of the entire thoracolumbar spine, or forward flexion of the thoracolumbar spine to 30 degrees or less. The Veteran does not have a diagnosis of lumbar spine intervertebral disc syndrome (IVDS) or degenerative disc disease (DDD). The Veteran does not have a diagnosis of radiculopathy of the lower extremities due to his lumbosacral strain. 16. From August 26, 2013 to the present, the Veteran's service-connected tension headaches are manifested by very frequent completely prostrating and prolonged attacks productive of severe economic inadaptability, absent the ameliorative effects of the medications he takes. CONCLUSIONS OF LAW 1. The criteria have not been met for direct service connection or presumptive service connection for GERD as due to exposure to contaminated water at Camp Lejeune or as a qualifying chronic disability under 38 C.F.R. § 3.317. 38 U.S.C. §§ 1110, 1117, 5107(b); 38 C.F.R. §§ 3.102, 3.303, 3.307, 3.309(f), 3.317 (2021). 2. The criteria have not been met for direct service connection or presumptive service connection for gastritis as due to exposure to contaminated water at Camp Lejeune or as a qualifying chronic disability under 38 C.F.R. § 3.317. 38 U.S.C. §§ 1110, 1117, 5107(b); 38 C.F.R. §§ 3.102, 3.303, 3.307, 3.309(f), 3.317 (2021). 3. Resolving all reasonable doubt in the Veteran's favor, the criteria have been met for service connection for PTSD based on in-service personal assaults / a pattern of harassment. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.304(f), 4.125(a). 4. The criteria have been met for service connection for major depressive disorder with associated anxiety, insomnia, and memory loss on a direct basis. 38 U.S.C. §§ 1110, 1154(a), 5107; 38 C.F.R. §§ 3.102, 3.303(a), (d), 4.125(b); Clemons v. Shinseki, 23 Vet. App. 1 (2009). 5. The criteria have been met for service connection for bowel disturbance with abdominal distress (an intestinal condition) under 38 C.F.R. § 3.317 as a qualifying chronic disability. 38 U.S.C. §§ 1110, 1117, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.317, 38 C.F.R. § 4.114, Diagnostic Code 7319. 6. The criteria have been met for service connection for type II diabetes mellitus under 38 C.F.R. § 3.317 as a qualifying chronic disability. 38 U.S.C. §§ 1110, 1117, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.317, 4.119, Diagnostic Code 7913. 7. The criteria have been met for service connection for hyperlipidemia (high cholesterol) with angina (chest pain). 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303; Saunders v. Wilkie, 886 F.3d 1356 (Fed. Cir. 2018). 8. The criteria have been met for secondary service connection for hypertension. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.310(a). 9. The criteria have been met for secondary service connection for diabetic peripheral neuropathy of the RIGHT lower extremity. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.310(a). 10. The criteria have been met for secondary service connection for diabetic peripheral neuropathy of the LEFT lower extremity. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.310(a). 11. The criteria have been for secondary service connection for an alcohol abuse disorder and polysubstance abuse disorder. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.310(a); Allen v. Principi, 237 F.3d 1368, 1376 (Fed. Cir. 2001). 12. The criteria have been met for a higher initial rating of 20 percent, but no greater, for a lumbosacral strain based on orthopedic manifestations. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1-4.14, 4.21, 4.40, 4.45, 4.59, 4.71a, Diagnostic Code 5237. 13. From August 26, 2013 to the present, the criteria have been met for the maximum 50 percent rating for the Veteran's service-connected tension headaches. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1-4.6, 4.10, 4.124a, Diagnostic Code 8100; Holmes v. Wilkie, 33 Vet. App. 67 (2020). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty from August 1988 to August 1992. This included service in the Southwest Asia theater of operations (in Saudi Arabia and Kuwait) from December 1990 to August 1991 during the Persian Gulf War. This matter comes to the Board of Veterans' Appeals (Board) on appeal from December 2015 and May 2018 rating decisions issued by an Agency of Original Jurisdiction (AOJ) of the Department of Veterans Affairs (VA). Multiple rating decisions are on appeal because the ratings for the Veteran's tension headaches disability have been staged by the AOJ for different periods of time. See Hart v. Mansfield, 21 Vet. App. 505, 509-10 (2007); Fenderson v. West, 12 Vet. App. 119, 126 (1999). That is, the AOJ assigned the Veteran 0 percent and 30 percent ratings for his tension headaches at different stages during the appeal. Presumably, the Veteran has continued to disagree with both the 0 percent and 30 percent ratings assigned for his tension headaches. See Breniser v. Shinseki, 25 Vet. App. 64, 79 (2011) (citing AB v. Brown, 6 Vet. App. 35, 38 (1993) (a veteran is presumed to be seeking the highest possible rating, unless he expressly indicates otherwise). In fact, in February 2016 and June 2018 NODs (VA Forms 21-0958), the Veteran explicitly expressed disagreement with both the 0 percent and 30 percent ratings for tension headaches assigned by the AOJ in each rating decision on appeal, and in a latter June 2018 VA Form 9, he perfected his appeal of both ratings to the Board. See 38 U.S.C. § 7105(a); 38 C.F.R. §§ 20.200, 20.202, 20.302(b) (2018) (redesignated as 38 C.F.R. §§ 19.20, 19.21, 19.22, 19.51, 19.52(a)-(b), effective February 19, 2019). With regard to a preliminary matter, in the present Board decision, for purposes of clarity, the Board will separately address both theories of etiology for the Veteran's GERD and gastritis disorders on appeal (direct service connection vs. secondary service connection). In doing so, the Board concludes that splitting up the previous two direct service connection issues for GERD and gastritis into four separate issues (now involving both direct service connection and secondary service connection) for independent adjudication is the most proper way of handling the Veteran's appeal. See Locklear v. Shinseki, 24 Vet. App. 311 (2011) (bifurcation of a claim generally is within VA's discretion); Tyrues v. Shinseki, 23 Vet. App. 166, 178-79 (2009), aff'd, 631 F.3d 1380 (Fed. Cir. 2011) (VA is free to dismember a claim and adjudicate it in separate pieces). On this point, when determining service connection, all theories of entitlement must be considered if raised by the evidence of record, applying all relevant laws and regulations. Szemraj v. Principi, 357 F.3d 1370, 1371 (Fed. Cir. 2004). The Federal Circuit has confirmed that the procedural history and statements by the claimant are relevant in determining the claimant's reasonable expectations and understanding, as service connection issues may be properly bifurcated and adjudicated separately if necessary. Murphy v. Wilkie, 983 F.3d. 1313, 1319 (Fed. Cir. 2020). "[A]lthough there may be multiple theories or means of establishing entitlement to a benefit for a disability, if the theories all pertain to the same benefit for the same disability, they constitute the same claim." Roebuck v. Nicholson, 20 Vet. App. 307, 313 (2006). In the instant case, the issues of service connection for GERD and gastritis on a direct basis are ripe for adjudication. In contrast, the separate issues of service connection for GERD and gastritis on a secondary basis require further development at the AOJ level, and thus, these secondary issues will be remanded to same. With regard to the TDIU issue on appeal, during the course of the increased rating appeals, the Veteran has submitted evidence of unemployability partially due to his service-connected headaches and lumbar spine, such that a request for TDIU was reasonably raised by the record. See 38 C.F.R. § 3.156(b); Rice v. Shinseki, 22 Vet. App. 447, 453-54 (2009) (a request for a TDIU, whether expressly raised by Veteran or reasonably raised by the record, is not a separate "claim" for benefits, but rather, can be part and parcel of a claim for an initial rating or increased rating for a disability). The Veteran also submitted a July 2022 Application for TDIU (VA Form 21-8940), which explicitly raised the TDIU issue. Moreover, the AOJ has already partially developed the TDIU issue (see, e.g., August 2022 VCAA letter). In this vein, the Board sees that the AOJ already sent the Veteran a VA Form 21-4192 (Request for Employment Information in Connection with Claim for Disability Benefit) and an extra VA Form 21-8940 (Application for Increased Compensation Based on Unemployability), included with the August 2022 VCAA notice letter. In short, the issue of entitlement to a TDIU has been added to the present appeal. In July 2019, the Board remanded the appeal for further development. This case has since been returned to the Board for appellate review, after the AOJ substantially complied with the Board's remand order. Stegall v. West, 11 Vet. App. 268, 271 (1998). Finally, throughout 2022, the Veteran's attorney submitted additional medical evidence, after certification of the Veteran's appeal. On this issue, under the provisions of 38 U.S.C. § 7105(e) (2018) for Legacy appeals, a waiver of AOJ consideration of new, pertinent evidence submitted by the Veteran or his representative after the appeal has been transferred to the Board is no longer required. In other words, under this statute, a waiver of AOJ consideration is presumed, absent a written request from the Veteran that the AOJ review the new evidence first. While the Veterans Appeals Improvement and Modernization Act of 2017 (AMA) deleted the provisions of 38 U.S.C. § 7105(e) (2018), the Public Law specified that Legacy appeals (such as the current appeal) were to be treated differently than appeals under the AMA. See Pub. L. 115-55 § 2(x)(1). In any event, in multiple July 2022 statements from the Veteran and his attorney, the Veteran explicitly waived his right to have the AOJ initially consider any additional evidence submitted after certification. In fact, the Veteran's attorney explicitly requested that the Board "adjudicate this Veteran's case without remand to the AOJ." The Board also emphasizes that in the case of an appeal returning to the Board after a remand to the AOJ, certification and initial transfer of the appellate record has already occurred, such that the 90-day limit for the submission of additional evidence listed under § 20.1304(a) (now substantively set forth under § 20.1305), no longer applies). See Williams v. Wilkie, 32 Vet. App. 46, 52-53 (2019). Therefore, the Board accepts all the additional medical evidence for inclusion in the record and consideration by the Board at this time, with or without a waiver. See 38 C.F.R. §§ 20.901, 20.1305(c) (2021). I. VA's Duty to Notify and Assist VA's duty to notify under the Veterans Claims Assistance Act of 2000 (VCAA) was satisfied by VA letters sent to Veteran, dated in April 2015, November 2019, August 2022, September 2022, and December 2022. See 38 U.S.C. §§ 5102, 5103, 5103A; 38 C.F.R. § 3.159 (2021). These letters advised the Veteran of the information and evidence necessary to substantiate his various service connection and increased rating claims on appeal. In any event, in the decision below, the Board has granted the Veteran's claims for service connection and secondary service connection for PTSD, major depression, alcohol and substance abuse disorders, a bowel disturbance, type II diabetes mellitus, hyperlipidemia (high cholesterol) with angina, hypertension, and bilateral lower extremity diabetic neuropathy. The Board has also granted in full the Veteran's claim for an increased rating for his tension headaches, by assigning the maximum 50 percent rating available under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. Therefore, the benefits sought on appeal have been granted in full for these particular service connection and increased rating issues. Accordingly, regardless of whether the notice and assistance requirements have been met, no harm or prejudice to the Veteran has resulted for these particular service connection and increased rating issues. See, e.g., Bernard v. Brown, 4 Vet. App. 384 (1993); VAOPGCPREC 16-92. With regard to the service connection and increased rating issues being denied in the present Board decision, subsequent to the ameliorative July 2019 Board remand, neither the Veteran nor his attorney has raised any issues with the duty to notify or duty to assist for these particular issues on appeal. See Scott v. McDonald, 789 F.3d 1375, 1381 (Fed. Cir. 2015) (holding that the Board has an obligation to read filings in a liberal manner, but that obligation does not require the Board to "search the record and address procedural arguments when the veteran fails to raise them before the Board."); Dickens v. McDonald, 814 F.3d 1359, 1361-62 (Fed. Cir. 2016) (applying Scott to a duty to assist argument). For example, in the July 2022 Attorney Brief and in a July 2022 Veteran statement, both written in response to the most recent AOJ adjudication of the appeal (the February 2022 SSOC), neither the Veteran nor his attorney requested another VA back examination to rate the current severity of his lumbosacral strain. Also, they did not allege the existence of any outstanding treatment records. Furthermore, neither the Veteran nor his attorney proffered any substantive argument or request for further development on the claims for direct service connection for GERD and gastritis, which are being denied by the Board. A claimant cannot remain passive if he has relevant information in favor of his claim. See Wamhoff v. Brown, 8 Vet. App. 517 (1996). The Veteran's attorney is reminded that it is a claimant's responsibility to support a claim for VA benefits, including submitting or specifically identifying relevant evidence and alleging specific errors of fact or law. See 38 U.S.C. §§ 5107 (a), 7105(d)(5). Counsel are expected to present arguments they deem material and relevant to their clients' cases. See Barela v. Peake, 22 Vet. App. 155, 159 (2008) (noting that an attorney has the ethical duty to educate himself about the relevant law, analyze the factual and legal elements of a case, adequately prepare, and zealously represent his client's interest); see also Andrews v. Nicholson, 421 F.3d 1278, 1282 (Fed. Cir. 2005). VA also afforded the Veteran VA esophageal and stomach examinations and opinions in November 2015, January 2022, and February 2022 that addressed whether his current GERD and gastritis disorders were related to his period of service in the Marine Corps. See McLendon v. Nicholson, 20 Vet. App. 79, 81 (2006); see also 38 U.S.C. § 5103A(d)(2); 38 C.F.R. § 3.159(c)(4). The VA examiner concluded that the Veteran's GERD and gastritis were not related to any specific toxic exposure experienced by the Veteran during his service in the Persian Gulf in the early 1990s. The VA examiner considered a variety of potential environmental hazards: exposure to smoke and particles from oil well fires; exposure to pesticides and insecticides; exposure to indigenous infectious diseases; exposure to solvent and fuel fumes; ingestion of pyridostigmine bromide tablets, as a nerve gas antidote; the combined effect of multiple vaccines administered upon deployment; inhalation of ultra fine-grain sand particles; and exposure to smoke and particles from military installation "burn pit" fires that incinerated a wide range of toxic waste materials. Significantly, neither the Veteran nor his attorney challenged the adequacy of the most recent January 2022 and February 2022 VA esophageal and stomach examinations and opinions. However, the Board is cognizant of the recent August 2022 passage of the Sergeant First Class Heath Robinson Honoring our Promise to Address Comprehensive Toxins Act of 2022 (PACT Act), Pub. L. No. 117-168, § 303 136 Stat. 1759, 1779 (2022). See also 38 U.S.C. §§ 1119, 1120. The PACT Act is a historic new law that expands VA health care and benefits for veterans exposed to burn pits and other toxic substances. The PACT Act requires VA examinations and opinions for veterans with presumed in-service exposure to Persian Gulf environmental hazards as part of VA's duty to assist, such as the Veteran in the present case. See 38 U.S.C. § 1168. On this point, VA claims processors have been instructed to review VBA Letter 20-22-10 (December 22, 2022) (VA Pact Act Policy Letter for Sub-Regulatory Guidance) when adjudicating a PACT Act claim involving a veteran's participation in a 'toxic exposure risk activity' (TERA). See 87 Fed. Reg. 78543 (Dec. 22, 2022). To that end, VBA Letter 20-22-10 (at pages 8-13) requires the VA claims processor to secure a VA examination and medical opinion for certain non-presumptive conditions when there is evidence of a veteran's involvement in a TERA, unless a listed exception applies. With that said, in the present case, for the GERD and gastritis disorders, the Board has determined that an additional VA examination under the PACT Act is unwarranted. In this vein, the VA esophageal and stomach examiner in January 2022 and February 2022, when providing unfavorable nexus opinions, already considered the Veteran's participation in all potential toxic exposure risk activities during his deployment to the Persian Gulf, as discussed above. Thus, yet another VA examination and opinion for the Veteran's GERD and gastritis disorders would be redundant, merely delay the adjudication of these claims, and serve no useful purpose. See Coburn v. Nicholson, 19 Vet. App. 427, 434 (2006) (Lance, J., dissenting) (noting that an unnecessary remand "perpetuates the hamster-wheel reputation of veterans law"). In conclusion, no prejudicial error is demonstrated in the present case by the Board's failure to secure an additional VA examination and opinion for these particular claims under the PACT Act. See Overton v. Nicholson, 20 Vet. App. 427, 434-35 (2006) (citing McDonough Power Equip. v. Greenwood, 464 U.S. 548, 553 (1984)). Therefore, the Board is satisfied that VA has provided all assistance required by the VCAA, for the service connection and increased rating issues being denied in the present Board decision. 38 U.S.C. § 5103A. II. Service Connection (SC) Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. § 3.303. The three-element test for service connection requires evidence of: (1) the existence of a current disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the current disability and the disease or injury incurred or aggravated during service the "nexus" requirement. Holton v. Shinseki, 557 F.3d 1363, 1366 (Fed. Cir. 2009) (quoting Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004)). VA is to give "due consideration" to "all pertinent medical and lay evidence" in evaluating a claim for disability benefits. 38 U.S.C. § 1154(a). Thus, there is no categorical rule that medical evidence is required when the determinative issue is either the existence of a current disability or a nexus to service. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. 2009). The Board should make explicit findings regarding the competency and, if necessary, the credibility of the lay evidence of record. Miller v Wilkie, 32 Vet. App. 249, 257-262 (2020). Lay testimony is competent to describe the presence of readily observable features or symptoms of injury or illness that are not medical in nature, such as varicose veins, tinnitus, and flat feet. See 38 C.F.R. § 3.159(a)(2); Barr v. Nicholson, 21 Vet. App. 303, 307-310 (2007). The Federal Circuit has also clarified that lay evidence can be competent for the medical diagnosis or etiology of a condition if: (1) the layperson is competent to identify the medical condition, (2) the layperson is reporting a contemporaneous medical diagnosis, or (3) lay testimony describing symptoms at the time supports a later diagnosis by a medical professional. Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). And if the disability is of the type for which lay evidence is competent, the Board must weigh the probative value of that lay evidence against other evidence of record in making its determination regarding the award of service connection. Buchanan v. Nicholson, 451 F.3d 1331, 1334-37 (Fed. Cir. 2006). In determining whether service connection is warranted, the Board shall consider the benefit-of-the-doubt doctrine. 38 U.S.C. 5107(b); 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49 (1991). The claimant is entitled to the benefit-of-the-doubt when the competing evidence is in "approximate balance" or "nearly equal." That is, exact equipoise is not required to trigger the favorable benefit-of-the-doubt rule. Lynch v. McDonough, 21 F.4th 776, 781 (Fed. Cir. 2021) (en banc). As a corollary, the Federal Circuit in Lynch also held that when the evidence "persuasively favors one side or the other," it is not in approximate balance, and the benefit-of-the-doubt rule does not apply. Id. at 782. A. GERD and Gastritis The Veteran contends that his GERD and gastritis disorders were caused by exposure to contaminants in the water supply at Camp Lejeune during his period of active service in the Marine Corps from 1988 to 1992. In the alternative, the Veteran contends that his GERD and gastritis resulted from his exposure to various toxic chemical and environmental hazards during his service in Southwest Asia (Saudi Arabia and Kuwait) in 1990 and 1991. Finally, the Veteran maintains that he has experienced signs and symptoms of GERD and gastritis such as acid reflux, epigastric distress, regurgitation, abdominal pain, indigestion, bloating, and nausea since 1990 (during his period of active service in the Marine Corps). Upon review of the evidence, service connection for both GERD (an esophageal condition) and gastritis (a stomach or duodenal condition), on a direct basis and on a presumptive basis, due to exposure to contaminated water at Camp Lejeune and as a qualifying chronic disability under 38 C.F.R. § 3.317, are denied. Gastroesophageal reflux disease (GERD) or "esophageal reflux" is defined as a condition involving regurgitation of the contents of the stomach into the esophagus, and possibly into the pharynx, with symptoms of burning pain and acid taste. See Stedman's Medical Dictionary 1520 (26th ed. 1995). "Gastritis" is defined as inflammation of the stomach. See Dorland's Illustrated Medical Dictionary 762 (32nd ed. 2012). Gastritis is a broad term, which encapsulates many specific manifestations. Gastritis is characterized by, among other things, "loss of appetite, nausea, abdominal pain, and vomiting." See Dorland's Illustrated Medical Dictionary, 757 (30th ed. 2003). Dorland's also notes that gastritis can be accompanied by bleeding and abscesses in the stomach wall. Id. The first and perhaps most fundamental requirement for either a direct or presumptive connection claim is proof the Veteran has a current disability. See 38 U.S.C. § 1110; 38 C.F.R. § 3.303(a); Degmetich v. Brown, 104 F.3d 1328, 1332 (1997). In the absence of proof of a current disability, there can be no valid claim. Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000). In the present case, clinical evidence of record has established current diagnoses of GERD and gastritis disabilities for the Veteran. See May 2009 private Physicians Immediate Care record; August 2013 VA nursing outpatient note; November 2015 VA esophageal examination; January 2022 VA stomach and duodenal examination; January 2022 VA esophageal examination; and February 2022 VA addendum opinion on stomach. The Veteran is prescribed omeprazole and milk of magnesia (MOM) to control his GERD / heartburn / acid reflux. In short, the above evidence is sufficient to establish current diagnoses of GERD and gastritis. The Veteran therefore meets this threshold criterion for service connection of current gastritis and GERD disabilities. See 38 U.S.C. § 1110; 38 C.F.R. § 3.303(a). With regard to presumptive service connection, effective March 14, 2017, a veteran or former reservist or member of the National Guard who had no less than 30 days (consecutive or nonconsecutive) of service at Camp Lejeune during the period beginning on August 1, 1953, and ending on December 31, 1987, shall be presumed to have been exposed during such service to contaminants in the water supply, unless there is affirmative evidence to the contrary. 38 C.F.R. § 3.307(a)(7)(iii). See also Diseases Associated with Exposure to Contaminants in the Water Supply at Camp Lejeune, 82 Fed. Reg. 4173, 4184-85 (Jan. 13, 2017). For purposes of the Camp Lejeune presumption, "contaminants in the water supply" means the volatile organic compounds trichloroethylene (TCE), perchloroethylene (PCE), benzene and vinyl chloride, that were in the on-base water-supply systems located at United States Marine Corps Base Camp Lejeune, during the period beginning on August 1, 1953, and ending on December 31, 1987. 38 C.F.R. § 3.307(a)(7)(i). "Service at Camp Lejeune" means any service within the borders of the entirety of the United States Marine Corps Base Camp Lejeune and Marine Corps Air Station New River, North Carolina, during the period beginning on August 1, 1953, and ending on December 31, 1987, as established by military orders or other official service department records. 38 C.F.R. § 3.307 (a)(7)(iii). In order to establish presumptive service connection for a disease associated with exposure to contaminated water at Camp Lejeune, a claimant must show the following: (1) that the veteran served at Camp Lejeune for no less than 30 days (either consecutive or nonconsecutive) from August 1, 1953 to December 31, 1987; (2) that the veteran suffered from a disease associated with exposure to contaminants in the water supply at Camp Lejeune enumerated under 38 C.F.R. § 3.309(f); and (3) that the disease process manifested to a degree of 10 percent or more at any time after service. 38 C.F.R. §§ 3.307(a)(7), 3.309(f). Stated another way, if the evidence confirms that a veteran, or former reservist or member of the National Guard, was exposed to contaminants in the water supply at Camp Lejeune during active service and the exposure meets the above requirements of § 3.307(a)(7), the following diseases shall be presumptively service-connected, even though there is no record of such disease during service, subject to the rebuttable presumption provisions of § 3.307(d): kidney cancer; liver cancer; non-Hodgkin's lymphoma; adult leukemia; multiple myeloma; Parkinson's disease; aplastic anemia and other myelodysplastic syndromes; and bladder cancer. 38 C.F.R. § 3.309(f). Provided, however, that such disease shall have become manifest to a degree of 10 percent or more at any time after service. 38 C.F.R. § 3.307(a)(7)(ii). With regard to presumptive service connection based on exposure to contaminated water at Camp Lejeune, the Veteran's service personnel records (SPRs) do not establish that he served at the Camp Lejeune Marine Corps Base for no less than 30 days (either consecutive or nonconsecutive) from August 1, 1953 to December 31, 1987. 38 C.F.R. § 3.307(a)(7)(iii). Instead, his SPRs and DD Form 214 indicate that he served in the Marine Corps from August 1988 to August 1992, after the required time period. Therefore, he is not presumed to have been exposed to contaminants in the water supply during his active duty at Camp Lejeune. Id. However, for purposes of this decision, the Board will assume the Veteran served during the required time period, such that he is presumed to have been exposed to contaminants in the water supply at Camp Lejeune, especially since his DD Form 214 documents nearly a year of prior inactive service in the Marine Corps Reserve, prior to his period of active duty service that began in August 1988. Id. Regardless, neither the Veteran's GERD nor his gastritis is on the list of diseases associated with contaminants in the water supply at Camp Lejeune for purposes of awarding presumptive service connection. 38 C.F.R. § 3.309(f). In other words, his GERD and his gastritis are not one of the presumptive Camp Lejeune disabilities. Id. Thus, although he may have been exposed to contaminated water at Camp Lejeune during his service in the Marine Corps, the Veteran is not entitled to service connection for his either his GERD or his gastritis on a presumptive basis under 38 C.F.R. § 3.309(e). With regard to direct service connection, under the Camp Lejeune Act of 2012, VA has also recognized 15 "covered illnesses" or "conditions" that it will assume are attributable to a veteran's active duty service at Camp Lejeune, but for treatment purposes only. See 38 U.S.C. § 1710(e); 38 C.F.R. § 17.400(b). A "covered illness or condition" means any of the following illnesses and conditions: (i) esophageal cancer; (ii) lung cancer; (iii) breast cancer; (iv) bladder cancer; (v) kidney cancer; (vi) leukemia; (vii) multiple myeloma; (viii) myelodysplastic syndromes; (ix) renal toxicity; (x) hepatic steatosis; (xi) female infertility; (xii) miscarriage; (xiii) scleroderma; (xiv) neurobehavioral effects; and (xv) non-Hodgkin's lymphoma. Id. For a Camp Lejeune veteran, VA will assume that a "covered illness or condition" listed above is attributable to the veteran's active duty service at Camp Lejeune unless it is clinically determined, under VA clinical practice guidelines, that such an illness or condition resulted from a cause other than such service. 38 C.F.R. § 17.400(c). VA has determined that manifestation of any of the above diseases in a veteran with verified Camp Lejeune service between 1957 and 1987 is sufficient to request a VA medical examination and an opinion regarding its relationship to Camp Lejeune service. However, in the present case, neither the Veteran's current GERD nor his current gastritis is on this list of "covered illnesses or conditions" assumed attributable to service for treatment purposes only under 38 C.F.R. § 17.400(b). As such, this provision does not assist the Veteran in his appeal of the GERD and gastritis issues. With regard to the Persian Gulf presumption, service connection is granted for Persian Gulf veterans suffering from a chronic disability resulting from an undiagnosed illness or medically unexplained chronic multi-symptom illness (MUCMI) that became manifest during active duty in the Southwest Asia theater of operations or became manifest to a compensable degree within the prescribed presumptive period. 38 U.S.C. § 1117; 38 C.F.R. § 3.317. If not manifest in service, the claimed chronic disability must have been manifest to a degree of 10 percent or more by December 31, 2026. 38 C.F.R. § 3.317(a)(1)(i). A "Persian Gulf veteran" is one who served in the Southwest Asia Theater of operations during the Persian Gulf War. See 38 C.F.R. § 3.317(e)(1). The Southwest Asia Theater of operations refers to Iraq, Kuwait, Saudi Arabia, the neutral zone between Iraq and Saudi Arabia, Bahrain, Qatar, the United Arab Emirates, Oman, the Gulf of Aden, the Gulf of Oman, the Persian Gulf, the Arabian Sea, the Red Sea, and the airspace above these locations. 38 C.F.R. § 3.317(e)(2). The term 'qualifying chronic disability' means a chronic disability resulting from any of the following (or any combination of the following): (A) an undiagnosed illness; (B) a medically unexplained chronic multisymptom illness (MUCMI) that is defined by a cluster of signs or symptoms, such as: (1) chronic fatigue syndrome; (2) fibromyalgia; (3) functional gastrointestinal disorders (excluding structural gastrointestinal diseases). 38 C.F.R. § 3.317(a)(2)(i). If probative evidence exists that the Veteran's disability pattern is either (1) an undiagnosed illness or (2) a diagnosable but medically unexplained chronic multisymptom illness (MUCMI) without conclusive etiology or pathophysiology, including but not limited to, chronic fatigue syndrome, fibromyalgia, or functional gastrointestinal disorders (excluding structural gastrointestinal diseases), then service connection must be granted for a Persian Gulf War illness. See 38 C.F.R. § 3.317(a)(2)(i) and (ii). The term "medically unexplained chronic multisymptom illness" (MUCMI) means a diagnosed illness without conclusive pathophysiology or etiology, that is characterized by overlapping symptoms and signs and has features such as fatigue, pain, disability out of proportion to physical findings, and inconsistent demonstration of laboratory abnormalities. Chronic multisymptom illnesses of partially understood etiology and pathophysiology, such as diabetes and multiple sclerosis, will not be considered medically unexplained. 38 C.F.R. § 3.317(a)(2)(ii). Under the proper interpretation of the law, the Court has held that an illness is a MUCMI where either the etiology or pathophysiology of the illness is inconclusive. But a multi-symptom illness is not a MUCMI where both the etiology and the pathophysiology of the illness are partially understood (thus conclusive). Stewart v. Wilkie, 30 Vet. App. 383, 390 (2018). For clarity, "pathophysiology" is defined as "the physiology of abnormal states; spec[ifically]: the functional changes that accompany a particular syndrome or disease." See Webster's Third New International Dictionary of the English Language Unabridged 1655 (1966); Stewart, 30 Vet. App. at 389-90, n.5. The Board may rely on a medical examiner's evaluation of whether a condition qualifies as a MUCMI. Goodman v. Shulkin, 870 F.3d 1383, 1387 (Fed. Cir. 2017). In individual MUCMI determinations, the VA adjudicator may consider evidence of a medical expert opinions and all other facts of record to make the final determination of whether a claimant has proven, based on the claimant's unique symptoms, the existence of a MUCMI. Id. Importantly, the Court has specifically held that GERD is not eligible for presumptive service connection as a MUCMI under 38 C.F.R. § 3.317. Atencio v. O'Rourke, 30 Vet. App. 74, 82-84 (2018). VA regulation clarifies that for a Persian Gulf illness, there must be "objective indications of a qualifying chronic disability," which include both "signs," in the medical sense of objective evidence perceptible to an examining physician, and other, non-medical indicators that are capable of independent verification. 38 C.F.R. § 3.317(a)(1) and (3). A disability is considered "chronic" if it has existed for six months or more or if the disability exhibits intermittent episodes of improvement and worsening over a six-month period. The sixth month period of chronicity will be measured from the earliest date on which the pertinent evidence establishes that the signs or symptoms of the disability first became manifest. 38 C.F.R. § 3.317(a)(4). Signs or symptoms which may be manifestations of an undiagnosed illness or a MUCMI include, but are not limited to, gastrointestinal signs or symptoms. 38 C.F.R. § 3.317(b)(10). With claims for service connection for a qualifying chronic disability under 38 C.F.R. § 3.317, the veteran is not required to provide competent evidence linking a current disability to an event during service. Gutierrez v. Principi, 19 Vet. App. 1, 8-9 (2004). That is, under 38 U.S.C. § 1117 and 38 C.F.R. § 3.317, the symptom, which is capable of lay observation, is presumed to be related to service, and unlike a claim of "direct service connection," VA cannot impose a medical nexus requirement. Further, lay persons such as the Veteran are competent to report objective signs of illness such as gastrointestinal pain. Id. at 9-10. To determine whether the undiagnosed illness is manifested to a degree of 10 percent or more the condition must be rated by analogy to a disease or injury in which the functions affected, anatomical location or symptomatology are similar. See 38 C.F.R. § 3.317(a)(5); see also Stankevich v. Nicholson, 19 Vet. App. 470, 472 (2006). The Board must explain its selection of analogous Diagnostic Code. Id. at 472. However, compensation shall not be paid under 38 C.F.R. § 3.317 for a chronic disability: (1) if there is affirmative evidence that the disability was not incurred during active military, naval, or air service in the Southwest Asia theater of operations; or (2) if there is affirmative evidence that the disability was caused by a supervening condition or event that occurred between the veteran's most recent departure from active duty in the Southwest Asia theater of operations and the onset of the disability; or (3) if there is affirmative evidence that the disability is the result of the veteran's own willful misconduct or the abuse of alcohol or drugs. 38 C.F.R. § 3.317(a)(7)(i-(iii). With regard to the Persian Gulf presumption, initially, service treatment records and service personnel records (STRs and SPRs) confirm that the Veteran served in the Southwest Asia theater of operations (Saudi Arabia and Kuwait) from December 1990 to August 1991, for purposes of establishing the Veteran's status as a "Persian Gulf veteran." 38 C.F.R. § 3.317(e)(1)(2). That is, he participated in counterinsurgency operations in Southwest Asia with the 11th Marine Expeditionary Unit (MEU). He was part of Operation Desert Shield and Operation Desert Storm. He also served in the waters of the Persian Gulf during this time period aboard the USS New Orleans (LPH-11). In fact, a recent January 2023 VA Memorandum advised that upon inquiry, the Department of Defense has (DoD) verified the Veteran has at least one qualifying deployment that satisfies the criteria for designation as a Persian Gulf Veteran as defined by 38 U.S.C §1117 and 38 CFR 3.317(e). With regard to the Persian Gulf presumption, "gastrointestinal signs or symptoms" are listed among the possible manifestations of an undiagnosed illness or medically unexplained chronic multi-symptom illness (MUCMI) for purposes of presumptive service connection. 38 U.S.C. § 1117(g)(10); 38 C.F.R. § 3.317(b)(10). Regardless, there is no probative evidence of record establishing a chronic disability pattern for the Veteran's "gastrointestinal signs or symptoms" due to his GERD or gastritis that is (1) an undiagnosed illness or (2) a diagnosable but medically unexplained chronic multi-symptom illness (MUCMI) without conclusive pathophysiology or etiology. See 38 C.F.R. § 3.317(a)(2)(i) and (ii). No military, private, or VA medical professional of record has made such as assessment. In fact, the January 2022 VA esophageal examiner concluded the Veteran's GERD is a disease "with a clear and specific etiology and diagnosis" and is not related to a specific exposure event experienced by the Veteran during his service in Southwest Asia. The VA examiner explained that GERD occurs when stomach acid backflows from the stomach into the esophagus. This backflow typically is caused from an abnormality of the esophageal sphincter in which it is either weak or abnormally relaxes. This is a structural issue. It cannot be linked to service in Southwest Asia. The VA examiner added that private upper endoscopies diagnosed GERD in the early 2000s. See also November 2015 VA esophageal examination. The Board emphasizes that a Persian Gulf disability must not be attributed to any known clinical diagnosis by history, physical examination, or laboratory test. 38 C.F.R. § 3.317(a)(1)(ii). Similarly, the January 2022 VA stomach and duodenal examiner assessed that the Veteran's gastritis is a disease with "a clear and specific etiology and diagnosis." It is not related to a specific exposure event experienced by the Veteran during service in Southwest Asia. Gastritis is a condition that inflames the stomach lining causing belly pain, indigestion, bloating and nausea, which the Veteran has. In October 2021 the Veteran's abdominal ultrasound (UA) testing was abnormal with "UProt-100." The VA examiner surmised stomach GERD and gastritis are more than likely closely related. That is, veterans with GERD will likely exhibit some form of gastric pathology. The VA examiner added that in this Veteran's case he likely has gastritis with nonspecific reactive changes. In light of the above evidence, the VA examiner has described a conclusive or partially understood etiology and pathophysiology for the Veteran's GERD and gastritis disabilities, thus negating the possibility of either being classified as a MUCMI. 38 C.F.R. § 3.317(a)(2)(ii); Stewart, 30 Vet. App. at 390. And once again, the Court has specifically held that GERD is not eligible for presumptive service connection as a MUCMI under 38 C.F.R. § 3.317. Atencio, 30 Vet. App. at 82-84. In making this determination, the Board acknowledges that lay persons such as the Veteran are competent to report objective signs of illness such as gastrointestinal pain and other, non-medical indicators that are capable of independent verification. 38 C.F.R. § 3.317(a)(3); Gutierrez, 19 Vet. App. at 9-10. However, although the Veteran is competent and credible in his description of recurrent acid reflux, epigastric distress, regurgitation, abdominal pain, indigestion, bloating, and nausea, the VA examiner in January 2022 and February 2022 medical opinions has attributed these signs and symptoms to diagnoses of GERD and gastritis with a nonservice related etiology and pathophysiology. Finally, neither the Veteran's GERD nor his gastritis can be designated as a "functional gastrointestinal disorder" in the present case, as his GERD and gastritis have been explained in the clinical evidence of record by structural, endoscopic, laboratory, or other objective signs of injury or disease. See 38 C.F.R. § 3.317(a)(2)(i)(B)(3). In summary, presumptive service connection for a Persian Gulf disability under 38 U.S.C. § 1117 and 38 C.F.R. § 3.317 is not warranted in this case for the Veteran's GERD or gastritis disabilities. However, this does not preclude the Veteran from establishing entitlement to service connection for the Veteran's unlisted GERD or gastritis with proof of actual direct causation. Combee, 34 F.3d at 1043. That is, if the claimed disease is not one of the presumptive Camp Lejeune diseases listed in 38 C.F.R. § 3.309(f), but exposure to contaminants in the water supply at Camp Lejeune is presumed or proven by the evidence, as is the case here, the Veteran may still establish service connection for his GERD or gastritis by (1) showing that the GERD or gastritis actually began during service; or (2) by submitting evidence of a nexus between the Veteran's GERD or gastritis and his presumed exposure to contaminated water at Camp Lejeune during service. Combee, 34 F.3d at 1043-1044. In this regard, under 38 C.F.R. § 3.303(d), disorders diagnosed after discharge may also still be service connected if all the evidence, including pertinent service records, establishes the disorder was incurred in service. In fact, with regard to direct service connection, the VA Adjudication Procedures Manual (M21-1) provides that VA is also required to consider service connection on a direct basis for any other disease not listed in 38 C.F.R. § 3.309(f) that is alleged to have been caused by the contaminants in the water supply at Camp Lejeune if there is (1) evidence of a current disease or disability, (2) evidence of exposure to the contaminated water at Camp Lejeune while on active duty, and (3) a medical nexus between the two, supported by a sufficient scientific explanation. See M21-1, VIII.iii.8.B.1.a. (February 19, 2019). The Board has cited this particular M21-1 provision because it is potentially beneficial to the Veteran's case. See, e.g., Stover v. McDonough, 35 Vet. App. 394 (2022); Andrews v. McDonough, 34 Vet. App. 216, 223 (2021); Wilson v. McDonough, 35 Vet. App. 75, 80 (2021). Likewise, if the claimed disease is neither an undiagnosed illness nor a diagnosable but medically unexplained chronic multi-symptom illness (MUCMI) without conclusive pathophysiology or etiology under 38 C.F.R. § 3.317, but in-service exposure to Persian Gulf chemical and environmental hazards is presumed or proven by the evidence, as is the case here, the Veteran may still establish service connection for his GERD or gastritis by (1) showing that the GERD or gastritis actually began during service; or (2) by submitting evidence of a nexus between the Veteran's GERD or gastritis and his presumed exposure to chemical and environmental hazards during service in Southwest Asia. Combee, 34 F.3d at 1043-1044. However, with regard to direct service connection, the Veteran's service treatment records (STRs) dated from 1988 to 1992 are negative for any complaint, treatment, or diagnosis of GERD or gastritis. The Board acknowledges that the Veteran was treated for nausea and vomiting due to an egg allergy and a flu vaccine reaction according to November 1989, February 1990, and March 1990 STRs. He was also treated for nausea, vomiting, and cold symptoms due to a viral URI per March 1990 and May 1990 STRs. However, his stomach / digestive issues on those occasions during service were not assessed as being the result of GERD or gastritis. At his July 1992 STR separation examination, no GERD or gastritis was described by the Veteran or diagnosed by the military clinician. As such, the Veteran's STRs provide no evidence in support of in-service incurrence for his GERD or gastritis. See 38 C.F.R. § 3.303(a). Post-service, the Veteran has reported that signs and symptoms of GERD and gastritis have been present since 1990 (during his period of active duty). He has added that GERD and gastritis were not officially diagnosed until post-service private endoscopies were performed in the early 2000s. See November 2015 VA esophageal examination. Regardless, the Veteran may not establish continuity of symptomatology for his current GERD or gastritis disabilities in lieu of a medical nexus, as this avenue to service connection is only available for "chronic diseases" listed under 38 C.F.R. § 3.309(a), in which neither GERD nor gastritis is included. 38 C.F.R. § 3.303(b); Walker, 708 F.3d at 1336-37. Finally, with regard to a nexus, there is no probative medical evidence of record establishing a relationship between the Veteran's current GERD or gastritis and his presumed exposure to contaminated water at Camp Lejeune during service in the late 1980s. Holton, 557 F.3d at 1366. See also 38 C.F.R. § 3.303(a), (d). The Veteran did not submit any scientific or clinical evidence demonstrating a nexus between his current GERD or gastritis and his presumed Camp Lejeune contaminated water exposure. Absent such evidence of a nexus, direct service connection is not in order for the Veteran's GERD or gastritis disabilities. In fact, the January 2022 VA esophagus, stomach, and duodenal examiner opined that neither the Veteran's GERD nor his gastritis is related to a specific exposure event experienced by the Veteran during his service in Southwest Asia in 1990 and 1991. The VA examiner determined that his GERD was a "structural" issue that cannot be linked to service in Southwest Asia. He added that a veteran with GERD will also likely exhibit some form of gastric pathology, such as gastritis with nonspecific changes in this Veteran's case. Unlike GERD where the stomach acid irritates the esophagus, with gastritis the acid irritates and inflames the stomach mucosa. See also February 2022 VA addendum opinion on stomach. On a side note, although the Veteran is also presumed to have been exposed to "fine particulate matter" from burn pits during his service in the Southwest Asia theater of operations in 1990 and 1991, neither his GERD nor his gastritis is listed as one of the chronic diseases or rare cancers associated with exposure to "fine particulate matter. See 38 C.F.R. § 3.320 (2022); 86 Fed. Reg. 42724 - 42733 (August 5, 2021). Thus, service connection cannot be awarded on this presumptive basis as well. Accordingly, the evidence of record persuasively weighs against a finding of service connection for either GERD or gastritis, on either a direct or presumptive basis. 38 U.S.C. § 5107; 38 C.F.R. § 3.102; Lynch, 21 F.4th at 781-82. Therefore, the GERD and gastritis claims are denied. B. PTSD Service connection for PTSD has unique evidentiary requirements. It generally requires: (1) medical evidence diagnosing the condition in accordance with 38 C.F.R. § 4.125(a) (i.e., DSM-5); (2) credible supporting evidence that the claimed in service stressor actually occurred; and (3) medical evidence of a link between current symptomatology and the claimed in service stressor. 38 C.F.R. § 3.304(f). See also Cohen v. Brown, 10 Vet. App. 128 (1997). If VA determines either that the veteran did not engage in combat with the enemy or that the veteran did engage in combat, but that the alleged stressor is not combat related, the veteran's lay testimony, by itself, is not sufficient to establish the occurrence of the alleged stressor. Instead, the record must contain credible supporting evidence that corroborates the veteran's testimony or statements. 38 C.F.R. § 3.304(f); Stone v. Nicholson, 480 F.3d 1111 (Fed. Cir. 2007); Cohen v. Brown, 10 Vet. App. 128, 147 (1997); Moreau v. Brown, 9 Vet. App. 389, 395 (1996). With regard to an actual diagnosis of PTSD, lay persons are not categorically incompetent to speak on matters of medical diagnosis or etiology. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. 2009). The Board must consider the type of condition specifically claimed and whether it is readily amenable to lay diagnosis or probative comment on etiology. See Woehlaert v. Nicholson, 21 Vet. App. 456, 462 (2007). In this regard, the Federal Circuit has held that "PTSD is not the type of medical condition that lay evidence... is competent and sufficient to identify." Young v. McDonald, 766 F.3d 1348, 1352-53 (Fed. Cir. 2014). Regardless, the Board acknowledges the Veteran is competent to report psychiatric symptoms and stressors both during and after service. See 38 C.F.R. § 3.159(a)(2); Jandreau, 492 F.3d at 1377 (discussing that Veteran is competent to report a contemporaneous medical diagnosis); Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006) (discussing general competency of a Veteran to report psychiatric symptoms). In this case, the Veteran does not allege that he was in combat. Instead, the Veteran contends that he has PTSD attributable to personal assaults / a pattern of harassment that occurred multiple times during his period of active duty in the Marine Corps from 1988 to 1992. Specifically, beginning in 1988 during boot camp, Marine Corps drill instructors frequently physically assaulted the Veteran he was stripped naked in front of other service members while being beaten, hit, and slapped. In addition, while stripped naked, Marine Corps drill instructors made toxic, racially abusive remarks about the Veteran's African American heritage (such as monkey sounds and a lack of body hair). In short, he experienced intense hazing. The Veteran says that as a result of the in-service personal trauma, within a year he was engaging in alcohol abuse during active duty (e.g., he underwent an alcohol rehabilitation course during active duty after being arrested for driving while intoxicated). He asserts his in-service alcohol abuse was a "marker," demonstrating a behavior change due to the onset of his PTSD. Post-service, he developed a polysubstance abuse habit (cocaine, heroin, opioids, and marijuana). He maintains this was a form of "self-medication" for his mental anguish and shame that stemmed from service. Post-service, he also developed various mental health issues such as depression, anxiety, panic attacks, paranoia, isolation, lack of motivation, nightmares, hypervigilance, insomnia, and memory loss. Upon separation from service in 1992, he initially did not seek mental health treatment because of the stigma associated with it. Over time, the Veteran contends that he was diagnosed with PTSD resulting from the in-service personal assaults / pattern of harassment. See March 2015 Application for Compensation (VA Form 21-526EZ); February 2016 Statement in Support of Claim for PTSD (VA Form 21-0781); November 2018 Attorney Brief; July 2022 Veteran statement; and July 2022 Attorney Brief. The Veteran's PTSD claim is predicated on allegations of physical assaults and a pattern of harassment while he was in the Marine Corps. The Court has set a relatively low bar for interpreting a claim for PTSD as one involving a personal assault stressor for which the provisions of 38 C.F.R. § 3.304(f)(5) are applicable. See, e.g., Bradford v. Nicholson, 20 Vet. App. 200 (2006) (veteran alleged that his sergeant kicked him down a set of stairs). In this regard, VA has defined "personal trauma" in a broad sense. Personal trauma for the purpose of VA disability compensation claims based on PTSD refers broadly to stressor events involving harm perpetrated by a person who is not considered part of an enemy force. Examples include assault, battery, robbery, mugging, stalking, and harassment. Military sexual trauma (MST) is a subset of personal trauma and refers to sexual harassment, sexual assault, or rape that occurs in a military setting. See VA Adjudication Procedures Manual (M21-1), VIII.iv.1.E.1.a. (July 29, 2021). Because personal assault is an extremely personal and sensitive issue, many incidents are not officially reported, which creates a proof problem with respect to the occurrence of the claimed stressor. In such situations, it is not unusual for there to be an absence of service records documenting the events the veteran has alleged surrounding the assault. The victims of such trauma may not necessarily report the full circumstances of the trauma for many years after the trauma. See M21-1, VIII.iv.1.B.1.b. (July 29, 2021). Therefore, the Federal Circuit has held that VA cannot use the absence of service record documentation or a veteran's lack of report of in-service physical assault or sexual assault to military authorities as evidence to conclude that a sexual assault did not occur. AZ v. Shinseki, 731 F.3d 1303, 1318 (Fed. Cir. 2013). And for PTSD claims in general, corroboration of every detail of a claimed stressor, including the veteran's personal participation, is not required; rather, a veteran only needs to offer independent evidence of a stressful event that is sufficient to imply his or her personal exposure. See Pentecost v. Principi, 16 Vet. App. 124, 128 (2002) (quoting Suozzi v. Brown, 10 Vet. App. 307 (1997)). When a PTSD claim is based on in-service personal assault, evidence from sources other than the veteran's service records may corroborate the veteran's account of the stressor incident. 38 C.F.R. § 3.304(f)(5); see also Patton v. West, 12 Vet. App. 272, 277 (1999). Examples of such alternative evidence include but are not limited to the following: records from law enforcement authorities; rape crisis centers; mental health counseling centers, hospitals, or physicians; pregnancy tests or tests for sexually transmitted diseases; and statements from family members, roommates, fellow service members, or clergy. 38 C.F.R. § 3.304(f)(5) (emphasis added). Personal diaries and journals can also be relevant. See also M21-1, VIII.iv.1.E.1.c. (July 29, 2021). If primary evidence, such as STRs and SPRs, contain no explicit documentation that personal trauma occurred, and alternative sources of evidence do not provide credible supporting evidence of the trauma, evidence of behavioral changes around the time of, and after, the incident(s), may constitute a "marker" of a personal trauma PTSD stressor. The term "marker" means an indicator of the effect or consequences of the personal trauma on the Veteran. A marker could be one or more behavioral events, or a pattern of changed behavior. Even if there is no reference to the personal trauma, evidence of the behavior changes below may circumstantially support the possibility that the claimed stressor occurred. See M21-1, VIII.iv.1.E.1.d. (July 29, 2021). Evidence of behavior changes or "markers" following the claimed assault, which may constitute credible evidence of the stressor include, but are not limited to: a request for a transfer to another military duty assignment; deterioration in work performance; substance abuse; episodes of depression, panic attacks, or anxiety without an identifiable cause; or unexplained economic or social behavior changes. 38 C.F.R. § 3.304(f)(5) (emphasis added). In addition, other relevant behavior changes or "markers" include increased use of leave with no apparent reason; medical treatment at a clinic without any specific diagnosis; use of or increased interest in pregnancy or STD tests around the time of the incident; changes in prescription usage and over-the-counter usage; increased disregard for any type of authority; treatment for physical injuries around the time of the alleged trauma, but without mention of the actual trauma; and the breakup of a primary relationship. See M21-1, VIII.iv.1.E.1.d. (July 29, 2021). Notably, behavior changes can be verified through both documentary evidence and lay statements. Id. For personal assault PTSD claims, an after-the-fact medical opinion can also serve as the credible supporting evidence of the stressor. That is, VA examiners can interpret the evidence of record to confirm the occurrence of in-service sexual assaults, personal trauma, and harassment. 38 C.F.R. § 3.304(f)(5); Menegassi v. Shinseki, 638 F.3d 1379, 1383 (Fed. Cir. 2011). In fact, evidence of behavioral changes typically needs interpretation by a clinician in personal trauma claims. The VA examiner should determine whether credible factual evidence of behavior changes demonstrated by a veteran is consistent with the expected reaction or adjustment of a person who has been subjected to an assault. See M21-1, VIII.iv.1.E.1.e. (July 29, 2021). If the VA examiner offers a credible, unequivocal, and non-speculative assessment that the evidence of record is consistent with the occurrence of the claimed assault, that opinion can constitute credible supporting evidence that the claimed in-service stressor actually occurred. If the opinion is merely speculative, equivocal, contradictory, or otherwise insufficient for rating purposes, it should be returned for clarification. If the VA examiner determines that a personal assault did occur, the VA examiner should then opine whether or not the Veteran has PTSD due to the confirmed personal assault. Id. Upon review of the evidence, service connection for PTSD based on personal assaults / a pattern of harassment is granted. STRs dated from 1988 to 1992 fail to reveal a diagnosis of PTSD or any psychiatric condition for the Veteran or any specific documentation of an in-service personal assault or pattern of harassment. In any event, as to PTSD, an in-service diagnosis is not required. See 38 C.F.R. § 3.304(f). Nor is the documented occurrence of a personal assault in a veteran's STRs required or expected. See again AZ, 731 F.3d at 1318. However, the Veteran's STRs do show treatment for alcohol abuse, as will be discussed in more detail below. SPRs document that the Veteran's military occupational specialty (MOS) was a cook while serving in the Marine Corps from 1988 to 1992. Post-service, there are multiple references in VA treatment records and VA examinations advising that the Veteran was first treated for polysubstance abuse and mental health problems (depression and anxiety) sometime between 1996 and 1999, approximately four to seven years after separation from his Marine Corps service. He has undergone four to six inpatient alcohol and drug rehabilitation programs post-service. He has been arrested for four DUIs / DWIs due to his alcohol abuse. Post-service employer records dated in 2004 also reveal the Veteran was disciplined, fired, and even arrested due to mental health problems while on the job. An August 2004 VA preventive medicine risk assessment screening documented depression, insomnia, mental health problems, panic attacks, anger outbursts, bad temper, lack of concentration, anxiety, nervousness, memory loss, and reports of abuse and harassment during active duty. Post-service, the first official diagnosis of PTSD in the record is from an August 2011 positive VA PTSD screen. See also August 19, 2011 VA mental health initial evaluation note. Also, in 2012, private psychiatric progress notes from Dr. Marianne Geiger, MD., and Social Security Administration (SSA) disability records diagnosed the Veteran with PTSD due to racism / physical assaults that occurred in the Marine Corps. Crucially, there is credible corroboration the Veteran experienced the reported incidents of personal assaults / a pattern of harassment while serving in the Marine Corps from 1988 to 1992. This evidence includes behavior changes and a "marker" demonstrated by way of an in-service August 1989 Navy Alcohol and Drug Safety Action Program certificate of completion; a February 1989 to March 1989 STR hospitalization that recorded occasional in-service abuse of alcohol; August 1988, October 1989, and August 1991 STR dental health questionnaires documenting the "moderate" consumption of alcohol of 2-3 drinks per day; VA, private, and SSA mental health treatment records; and alternative evidence in the form of lay buddy statements from family and friends documenting in-service behavioral changes for the Veteran. See 38 C.F.R. § 3.304(f)(5); Cohen, 10 Vet. App. at 147; Moreau, 9 Vet. App. at 395. In particular, with regard to credible evidence that the in-service personal assaults / a pattern of harassment occurred, about a year into his period of active duty in the Marine Corps, STRs contain an August 1989 Navy Alcohol and Drug Safety Action Program certificate of completion. This was a 36-hour course for substance abuse by alcohol in-service at Camp Pendleton. The Veteran had been arrested for a DUI during active duty. Additionally, a February 1989 to March 1989 STR hospitalization recorded occasional in-service abuse of alcohol. Moreover, August 1988, October 1989, and August 1991 STR dental health questionnaires documented the "moderate" consumption of alcohol of 2-3 drinks per day for the Veteran. Also, post-service, VA and private clinical records discussed mental health symptoms and alcohol and substance abuse beginning in the 1990s a short time after service, without an identifiable cause. In this regard, the Board is cognizant that evidence of behavior changes or "markers" following the claimed assault, which may constitute credible evidence of the stressor, include substance abuse such as from alcohol. See 38 C.F.R. § 3.304(f)(5). In particular, with regard to credible evidence that the in-service personal assaults / a pattern of harassment occurred, the Board has considered July 2017 lay buddy statements from the Veteran's mother, his sister, and a childhood friend, corroborating the Veteran's behavior changes upon separation from service in 1992. They noticed that in 1992 the Veteran for the first-time displayed anger, depression, memory loss, anxiety, avoidance, and paranoia, among other mental health symptoms. He could not hold a job and began having problems with law enforcement beginning in 1992 and 1993. In 1993 he was kicked out of college at Arkansas State due to excess alcohol use. In this regard, the Board is cognizant that evidence of behavior changes or "markers" following the claimed assault, which may constitute credible evidence of the stressor, include unexplained social behavior changes. See 38 C.F.R. § 3.304(f)(5). Finally, with regard to credible evidence that the in-service personal assaults / a pattern of harassment occurred, the following clinical evidence in a manner of words assessed that the Veteran endured in-service personal assaults / a pattern of harassment while serving in the Marine Corps from 1988 to 1992. See 38 C.F.R. § 3.304(f)(5); Menegassi, 638 F.3d at 1383. In this regard, the following is credible evidence that the in-service personal assaults / a pattern of harassment occurred: August 2012 / September 2012 private psychiatric progress notes from Dr. Marianne Geiger, MD.; 2013 Social Security Administration (SSA) disability mental health records; an October 2015 VA mental health outpatient note by a VA social worker; a January 2014 VA mental health telehealth note by a VA psychiatrist; and a February 2017 VA mental health consult by a VA social worker. This above post-service clinical opinions serve as credible evidence of the occurrence of the in-service personal assaults / a pattern of harassment. Again, medical opinions in cases of personal assault for PTSD are exceptions to the general rule as, for example, announced in Moreau v. Brown, 9 Vet. App. 389, 396 (1996), that an opinion by a medical professional based on a post-service examination cannot be used to establish the occurrence of a stressor. 38 C.F.R. § 3.304(f)(3); Patton v. West, 12 Vet. App. 272, 280 (1999). For assault stressors, the examiner can interpret the meaning of behavioral changes during service to determine if an assault stressor did occur. Id. Here, VA and private and SSA clinicians accomplished this task, sometimes explicitly, and sometimes implicitly. With regard to a nexus to service for his PTSD, the evidence of record is mixed as to whether the Veteran has a current disability of PTSD, in accordance with 38 C.F.R. § 4.125(a) (i.e., DSM-5), as the result of the in-service personal assaults / a pattern of harassment that occurred during his period of active duty in the Marine Corps. See 38 C.F.R. § 3.304(f). That is, the record is mixed and reflects several favorable and unfavorable medical opinions as well as VA, SSA, and private treatment records and lay evidence pertinent to the nexus criterion necessary to establish service connection for PTSD based on personal assaults / a pattern of harassment. Simply stated, the evidence of record is at equipoise (approximately equal) on whether the Veteran has PTSD due to the in-service assaults and harassment from Marine Corps drill instructors from 1988 to 1992. 38 C.F.R. § 3.304(f)(5). The favorable evidence of a nexus for PTSD consists of the following: August 2012 / September 2012 private psychiatric progress notes from Dr. Marianne Geiger, MD.; 2013 SSA disability mental health records; an October 2015 VA mental health outpatient note by a VA social worker; a January 2014 VA mental health telehealth note by a VA psychiatrist; and a February 2017 VA mental health consult by a VA social worker. In contrast, the unfavorable evidence against a diagnosis or nexus for PTSD under the DSM-5 consists of the following: An October 2015 VA psychological examination and opinion; an April 2018 VA psychological examination and opinion; and a March 2021 VA psychological examination and opinion. However, it is significant that the VA examiners failed to discuss the Veteran's potential "marker" of in-service alcohol abuse, in rendering their negative opinions. The VA benefits system does not favor the opinion of a VA examiner over a private examiner, or vice versa. See 38 U.S.C. § 5125; White v. Principi, 243 F.3d 1378, 1381 (Fed. Cir. 2001) (declining to adopt the treating physician rule for adjudicating VA benefits). See also 38 C.F.R. § 3.326(b), (c) (2021) (stating that any examination report or statement from a private physician "may be accepted for rating a claim without further examination") (emphasis added). With regard to the favorable diagnosis of PTSD for the Veteran rendered by various VA, private, and SSA psychiatrists, psychologists, and social workers in clincial records dated from 2012 to 2017, the Board is aware that pursuant to 38 C.F.R. § 4.125(a), if the diagnosis of a mental disorder does not conform to DSM-5 or is not supported by the findings on the examination report, the rating agency shall return the report to the examiner to substantiate the diagnosis. However, mental health professionals are experts and are presumed to know the DSM-5 requirements applicable to their practice and to have taken them into account in providing a PTSD diagnosis. As such, the Court has held that a PTSD diagnosis provided by a mental-health professional must be presumed to have been made in accordance with the applicable DSM-IV (or DSM-5) criteria as to both the adequacy of the symptomatology and the sufficiency of the stressor, unless there is evidence to the contrary. Cohen v. Brown, 10 Vet. App. 128, 140 (1997). The DSM-IV (or DSM-5) cannot be used "as a basis for rejecting the Veteran's favorable medical evidence as to the sufficiency of a stressor or the adequacy of the Veteran's symptomatology." Id. As such, in order to make a finding that the Veteran in this case did not have a valid PTSD diagnosis, the Board must clearly articulate its reasons for finding that the PTSD diagnosis was not made in accordance with the DSM-IV or DSM-5 requirements. If the Board cannot support a conclusion that the diagnosis was not made in accordance with DSM-IV or DSM-5 requirements, it must accept the diagnosis as valid. In the present case, the Board will accept the above PTSD diagnoses rendered by the Veteran's VA, private, and SSA medical professionals from 2012 to 2017 as valid and in accordance with the DSM-5. The VA, private, and SSA psychiatrists, psychologists, and social workers described some of the reasons for their conclusions and also discussed the Veteran's underlying PTSD symptomatology and his in-service physical assaults / pattern of harassment. Nonetheless, the negative clinical evidence of record against service connection for PTSD also provides probative analysis as well. As currently codified, VA law defines the "benefit of the doubt" doctrine as: When, after consideration of all evidence and material of record in this case before the Department with respect to benefits under laws administered by the Secretary, there is an "approximate" balance of positive and negative evidence regarding the merits of an issue material to the determination in the matter, the benefit of the doubt in resolving each such issue shall be given to the claimant. 38 U.S.C. § 5107(b). See also 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49 (1990). In light of all the evidence discussed in detail above, the Board finds that there is an approximate balance of positive and negative evidence on the PTSD issue. Certain elements of both the positive and negative medical opinions and the mental health treatment records and lay statements in this case in this case are probative. All of the medical opinions and clinical evidence and lay evidence have their respective flaws as well. But there is no apparent basis for wholly rejecting the favorable medical opinions and clinical evidence of record. In light of the contrasting, yet equally probative medical opinions and clinical evidence and lay evidence in the present case, in such situations, the benefit of the doubt is resolved in the Veteran's favor. The Federal Circuit Court recently emphasized that under 38 U.S.C. § 5107(b) and under its previous holding of Ortiz v. Principi, 274 F.3d 1361 (Fed. Cir. 2001), the claimant is entitled to the benefit of the doubt when the evidence is in "approximate" balancei.e., "nearly equal"but does not require that the evidence be in exact equipoise. Lynch, 999 F.3d at 1394. In fact, in January 2023, the Federal Circuit Court in Mattox v. McDonough, 56 F.4th 1369, 1378-79 (Fed. Cir. 2023) concluded that in assessing whether the evidence is in "approximate balance" or in equipoise under 38 U.S.C. § 5107(b), VA does not simply tally up the number of pieces of evidence for and against the claim (count the positive and negative evidence). Instead, VA must assess the quality of this positive and negative evidence (by assessing the probative value, credibility, and weight of this evidence), to determine if the evidence is in approximate balance. Id. The Board in the instant Veteran's case has followed the rationale of the Federal Circuit's holding in Mattox. Applying the law to the evidence of record, the Board is compelled to grant the Veteran the benefit of the doubt and award service connection for PTSD due to in-service physical assaults / a pattern of harassment. See 38 U.S.C. § 5107(b); 38 C.F.R. §§ 3.102, 3.304(f)(5). The PTSD claim is granted. C. Major Depression / Anxiety / Insomnia / Memory Loss Despite awarding service connection for PTSD in the present Board decision, the Board (and the AOJ) have also considered whether service connection is warranted for all of the Veteran's psychiatric disorders identified in the record, in order to provide adequate consideration of his multiple mental health diagnoses. In this vein, VA must fully and sympathetically develop a veteran's claim to its optimum, and that requires VA to determine all potential claims raised by the evidence, applying all relevant laws and regulations. Moody v. Principi, 360 F.3d 1306, 1310 (Fed. Cir. 2004); Szemraj v. Principi, 357 F.3d 1370, 1371 (Fed. Cir. 2004). The U.S. Court of Appeals for Veterans Claims (Court) has held that a claimant's identification of the benefit sought does not require technical precision. See Ingram v. Nicholson, 21 Vet. App. 232, 256-57 (2007). Thus, the Board has considered all psychiatric symptoms and all psychiatric disorders identified in the record, when recharacterizing the Veteran's service connection claim for his psychiatric disorder (other than PTSD). See Clemons v. Shinseki, 23 Vet. App. 1 (2009) (the scope of a psychiatric disability claim includes any disability that may reasonably be encompassed by the claimant's description of the claim, reported symptoms, and the other information of record). Also, this rule also applies to non-mental health conditions. See Brokowski v. Shinseki, 23 Vet. App. 79 (2009) (applying Clemons to a neurological disorder). The Federal Circuit has advised that in determining the scope of a claim, VA must look to all possible diagnoses, conditions, and illnesses that a pro se non-expert claimant could have reasonably expected to have included in their claim as well as the clinical evidence developed in processing that claim. Murphy v. Wilkie, 983 F.3d. 1313, 1319 (Fed. Cir. 2020). VA need only explore conditions which "may be reasonably considered within the scope of the claim." Id. This was termed as the "Clemons lenient-claim-scope rule." Id. at 1318-1320. The Court has also held that the rule of Clemons v. Shinseki, 23 Vet. App. 1 (2009)i.e., the scope of a claim for service connection can encompass multiple conditionsapplies even when the diagnosis for a related condition referenced by the claimant is provided after the issuance of the AOJ decision on appeal for the original claim. Grimes v. McDonough, 34 Vet. App. 84 (2021). Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. § 3.303. In addition, disorders diagnosed after discharge may also still be service connected if all the evidence, including pertinent service records, establishes the disorder was incurred in service. 38 C.F.R. § 3.303(d). See Combee v. Brown, 34 F.3d 1039, 1043 (Fed. Cir. 1994). The Veteran dates the onset of all his current mental health problems to his active service in the Marine Corps from 1988 to 1992. Similar to his PTSD, the Veteran believes his depression and anxiety disorders stem from the personal assaults / a pattern of harassment that occurred multiple times during his period of active duty in the Marine Corps from 1988 to 1992. The description of these incidents has already been discussed in detail above. In short, he experienced intense hazing. Moreover, the Veteran served in a war zone in the Persian Gulf (in Saudi Arabia and Kuwait and aboard the USS New Orleans) from December 1990 to August 1991, with an always present fear of hostile military or terrorist activity. As a result of his in-service traumatic exposures, he began engaging in alcohol abuse during active duty (e.g., he underwent an alcohol rehabilitation course during active duty after being arrested for driving intoxicated). He began to exhibit behavior changes by his final year of service in 1992 but did not report his psychiatric symptoms to Marine Corps clinicians, due to the stigma of being perceived as weak. Post-service, a short time after service, he developed a polysubstance abuse habit (cocaine, heroin, opioids, and marijuana). He maintains this was a form of "self-medication" for his mental anguish and shame that stemmed from service. Post-service beginning in the 1990s, various mental health problems gradually worsened - such as depression, anxiety, panic attacks, paranoia, isolation, lack of motivation, nightmares, hypervigilance, insomnia, and memory loss. See August 2013 informal claim for service connection; March 2015 Application for Compensation (VA Form 21-526EZ); February 2016 NOD (VA Form 21-0958); March 2019 Veteran statement; November 2018 Attorney Brief; July 2022 Veteran statement; and July 2022 Attorney Brief. Upon review of the evidence, service connection for major depressive disorder with associated anxiety, insomnia, and memory loss is granted. Initially, none of the psychiatric disorders at issue on appeal are one of the enumerated "chronic disease[s]" listed under 38 C.F.R. § 3.309(a); therefore, the presumptive provisions based on "chronic" symptoms in service and "continuous" symptoms since service at 38 C.F.R. § 3.303(b) do not apply here. Walker v. Shinseki, 708 F.3d 1331, 1338-39 (Fed. Cir. 2013). Instead, 38 C.F.R. § 3.303(a) and (d) apply in the present case for the psychiatric disorder(s) on appeal. That is, none of the Veteran's current psychiatric disorders are listed as a "psychosis" under 38 C.F.R. § 3.384. The first and perhaps most fundamental requirement for any service-connection claim is proof the Veteran has a current disability. See 38 U.S.C. § 1110; 38 C.F.R. § 3.303(a); Degmetich v. Brown, 104 F. 3d 1328, 1332 (1997). Here, VA, private, and SSA clinicians in treatment records dated from 2004 to 2022 have diagnosed the Veteran with multiple psychiatric diagnoses: depression NOS, major depressive disorder (MDD), unspecified anxiety disorder, bipolar disorder, schizoaffective disorder, intermittent explosive disorder, and a mood disorder NOS. See also July 2013 Rosecrance private mental health assessment; December 2013 private psychological evaluation from Psychology Consultants, P.C.; September 2017 private psychological evaluation and opinion by Heather Henderson-Galligan, psychologist; April 2018 VA psychological examination; and March 2021 VA psychological examination. The Veteran has also received a diagnosis of chronic PTSD, which has already been service-connected as discussed in great detail above. In any event, the Veteran has been treated for his various mental health problems post-service by way of therapy and various psychiatric medications. Thus, it is undisputed the Veteran has current psychiatric disorders. As to the second requirement of in-service incurrence, the Veteran's STRs dated from 1988 to 1922 are negative for any complaint, treatment, or diagnosis of a psychiatric disorder for the Veteran. However, as already noted above, STRs contain an August 1989 Navy Alcohol and Drug Safety Action Program certificate of completion. This was a 36-hour course for substance abuse by alcohol in-service at Camp Pendleton. The Veteran had been arrested for a DUI during active duty. What's more, a February 1989 to March 1989 STR hospitalization recorded occasional in-service abuse of alcohol. STR dental health questionnaires dated in August 1988, October 1989, and August 1991 documented the "moderate" consumption of alcohol of 2-3 drinks per day for the Veteran. In addition, SPRs confirm the Veteran served in the Persian Gulf, Kuwait, and Saudi Arabia in 1990 and 1991 during the Persian Gulf War. A SPR "combat history and expeditions" document confirms the Veteran Participated on Operation Desert Shield and Operation Desert Storm while serving in Southwest Asia. His SPRs also confirm he participated in counterinsurgency operations in Southwest Asia with the 11th Marine Expeditionary Unit (MEU) from March 1991 to July 1991. VA psychological examiners in April 2018 and March 2021 opined that the Veteran would have had a fear of hostile military or terrorist activity during his service in the Persian Gulf (but they assessed no PTSD as a result of this). In any event, a fear of hostile military or terrorist activity during active duty (without actual combat exposure) is consistent with the places, types, and circumstances of his service in the Marine Corps in 1990 and 1991 in the Persian Gulf. See 38 U.S.C. § 1154(a); 38 C.F.R. § 3.303(a). Thus, the second element of service connection is met here in terms of the occurrence of a traumatic in-service event or incident. See 38 C.F.R. § 3.303(a). Post-service, with regard to clinical evidence, there are multiple references in VA treatment records and VA examinations advising that the Veteran was first treated for polysubstance abuse and mental health problems (depression and anxiety) sometime between 1996 and 1999, approximately four to seven years after separation from his Marine Corps service. He has undergone four to six inpatient alcohol and drug rehabilitation programs post-service. He has been arrested for four DUIs / DWIs due to his alcohol abuse. Post-service employer records dated in 2004 also reveal the Veteran was disciplined, fired, and even arrested due to mental health problems while on the job. An August 2004 VA preventive medicine risk assessment screening documented depression, insomnia, mental health problems, panic attacks, anger outbursts, bad temper, lack of concentration, anxiety, nervousness, memory loss, and reports of abuse and harassment during active duty. Post-service, with regard to lay evidence, the Veteran, his family, and a friend have submitted competent and credible lay and buddy statements asserting ongoing psychiatric symptoms after separation from active duty in August 1992. See 38 C.F.R. § 3.159(a)(2); Jandreau, 492 F.3d at 1377 (discussing that a lay person is competent to report a contemporaneous medical diagnosis); Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006) (discussing general competency of a veteran or others to report observable psychiatric symptoms). In this regard, the Board has considered July 2017 lay "buddy" statements from the Veteran's mother, his sister, and a childhood friend corroborating the Veteran's behavior changes upon separation from service in 1992. They noticed that in 1992 the Veteran for the first-time displayed anger, depression, memory loss, anxiety, avoidance, and paranoia, among other mental health symptoms. He could not hold a job and began having problems with law enforcement beginning in 1992 and 1993. In 1993 he was kicked out of college at Arkansas State due to excess alcohol use. The Board finds these lay reports of mental health difficulties beginning in 1992 upon separation from service to be credible, as they are confirmed by certain post-service VA, private, and SSA clinical records as well. Barr, 21 Vet. App. at 308 (observing that once evidence is determined to be competent, the Board must determine whether such evidence is also credible). These lay "buddy" statements are consistent with each other in their descriptions of the Veteran's gradually worsening mental health symptoms starting in 1992, immediately out of service. Post-service, with regard to lay evidence, the Board also finds the Veteran's lay reports of ongoing mental health difficulties after separation from service in 1992 to be somewhat credible, even though he did not receive any formal mental health treatment / substance abuse treatment until sometime between 1996 and 1999, according to latter VA, SSA, and private clinical records dated in the 2000s. Barr, 21 Vet. App. at 308 (observing that once evidence is determined to be competent, the Board must determine whether such evidence is also credible). Statements made for the purpose of medical diagnosis or treatment are exceptionally trustworthy because the declarant has a strong motive to tell the truth in order to receive a proper diagnosis or treatment. White v. Illinois, 502 U.S. 346, 355-56 (1991). Post-service, as to the third requirement of a nexus, the claims file contains a mix of favorable and unfavorable medical opinions and medical treatise evidence on whether there is a nexus or link between the Veteran's current psychiatric disorders and his documented in-service alcohol abuse and traumatic exposures in the Persian Gulf. Holton, 557 F.3d at 1366. See also 38 C.F.R. § 3.303(a), (d). The favorable evidence of a nexus to service for major depressive disorder with associated anxiety, insomnia, and memory loss consists of the following: an August 2011 VA mental health risk assessment screening note; and August 2011 VA mental health initial evaluation note; and October 2011 VA mental health outpatient treatment plan note; a December 2013 private social worker letter from Glenwood Center; a January 2014 VA mental health telehealth note by a VA psychiatrist; a September 2017 private psychological evaluation and opinion by Heather Henderson-Galligan, psychologist; a December 2013 private psychological evaluation from Psychology Consultants, P.C.; a December 2012 VA medical treatise article titled "The Effect of Depression on the Association between Military Service and Life Satisfaction"; and a 2013 Research Article in the Depression and Anxiety Journal titled "Guilt, Shame, and Suicidal Ideation in a Military Outpatient Clinical Sample." In contrast, the unfavorable evidence against a nexus to service for major depressive disorder with associated anxiety, insomnia, and memory loss consists of the following: an October 2015 VA psychological examination; an April 2018 VA psychological examination with a medical opinion; and a March 2021 VA psychological examination and opinion. Once again, the VA benefits system does not favor the opinion of a VA examiner over a private examiner, or vice versa. See 38 U.S.C. § 5125; White v. Principi, 243 F.3d 1378, 1381 (Fed. Cir. 2001) (declining to adopt the treating physician rule for adjudicating VA benefits). See also 38 C.F.R. § 3.326(b), (c) (2021) (stating that any examination report or statement from a private physician "may be accepted for rating a claim without further examination") (emphasis added). And once again, as currently codified, VA law defines the "benefit of the doubt" doctrine as: When, after consideration of all evidence and material of record in this case before the Department with respect to benefits under laws administered by the Secretary, there is an "approximate" balance of positive and negative evidence regarding the merits of an issue material to the determination in the matter, the benefit of the doubt in resolving each such issue shall be given to the claimant. 38 U.S.C. § 5107(b). See also 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49 (1990). Here, there is an approximate balance of the positive and negative evidence on the issue of service connection for major depressive disorder with associated anxiety, insomnia, and memory loss. Certain elements of both the positive and negative medical opinions and clinical and lay evidence of record in this case are probative. All of the medical opinions and clinical evidence and lay evidence have their respective flaws as well. But there is no apparent basis for wholly rejecting the favorable medical opinions and clinical and lay evidence of record. In light of the contrasting, yet equally probative medical opinions and clinical evidence and lay evidence in the present case, in such situations, the benefit of the doubt is resolved in the Veteran's favor. The Federal Circuit Court recently emphasized that under 38 U.S.C. § 5107(b) and under its previous holding of Ortiz v. Principi, 274 F.3d 1361 (Fed. Cir. 2001), the claimant is entitled to the benefit of the doubt when the evidence is in "approximate" balancei.e., "nearly equal"but does not require that the evidence be in exact equipoise. Lynch, 999 F.3d at 1394. Accordingly, resolving doubt in the Veteran's favor, the evidence supports service connection for major depressive disorder with associated anxiety, insomnia, and memory loss. 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102. The claim is granted. On a side note, during the course of the appeal, the Veteran has been diagnosed with multiple psychiatric diagnoses: PTSD, depression NOS, major depressive disorder (MDD), unspecified anxiety disorder, bipolar disorder, schizoaffective disorder, intermittent explosive disorder, and a mood disorder NOS. In this regard, VA regulation provides that if the diagnosis of a mental disorder is changed, the rating agency shall determine whether the new diagnosis represents progression of the prior diagnosis, correction of an error in the prior diagnosis, or development of a new and separate condition. 38 C.F.R. § 4.125(b) (2021). If it is not clear from the available records what the change of diagnosis represents, the rating agency shall return the report to the examiner for a determination. Id. Nevertheless, the Board concludes from the clinical evidence of record that major depressive disorder with associated anxiety, insomnia, and memory loss and PTSD are the most accurate diagnoses rendered for the Veteran's mental health impairment. In fact, the March 2021 VA psychological examiner opined that an earlier diagnosis of bipolar disorder by VA clinicians was "incorrect," given the Veteran's report of symptoms and his accompanying substance abuse. As to the diagnoses of intermittent explosive disorder in July 2013 and schizoaffective disorder in December 2013 by private psychologists, no other VA, SSA, or private clinician diagnosed the Veteran with these particular mental health conditions. In any event, the Board emphasizes that the Veteran's now service-connected diagnoses discussed above encompass all of his psychiatric signs and symptoms, regardless of technical differences between VA, private, and SSA clinicians in assessing the precise DSM-5 diagnosis for this Veteran. To that end, the present decision is considered a full grant of the benefits sought by the Veteran for his acquired psychiatric disorder claim. In granting service connection for PTSD, as well as service connection for major depressive disorder with associated anxiety, insomnia, and memory loss, the AOJ should assign a disability rating or ratings that encompass the symptoms of these disorders. See Amberman v. Shinseki, 570 F.3d 1377, 1381 (2009) (two defined diagnoses constitute the same disability for purposes of 38 C.F.R. § 4.14 if they have overlapping symptomatology, but bipolar disorder and PTSD could have different symptoms and it could therefore be improper in some circumstances for VA to treat these separately diagnosed conditions as producing only the same disability). D. Bowel Disturbance with Abdominal Distress (An Intestinal Condition) The Veteran contends that his lower stomach / intestinal problems such as constipation and diarrhea and melena resulted from his exposure to various toxic chemical and environmental hazards during his service in Southwest Asia (Saudi Arabia and Kuwait) in 1990 and 1991. The Veteran maintains that he has experienced constipation and lower stomach intestinal pain since boot camp in 1988 during his period of active service in the Marine Corps. He has reported several colonoscopies which were unremarkable. Thus, he believes he has a Persian Gulf undiagnosed illness for his lower stomach bowel disturbance. Upon review of the evidence, service connection for a bowel disturbance with abdominal distress (an intestinal condition) as a qualifying chronic disability under 38 C.F.R. § 3.317 is granted. With regard to the Persian Gulf presumption, initially, STRs and SPRs and a recent January 2023 VA Memorandum confirm that the Veteran served in the Southwest Asia theater of operations (Saudi Arabia and Kuwait) from December 1990 to August 1991, for purposes of establishing the veteran's status as a "Persian Gulf veteran." 38 C.F.R. § 3.317(e)(1)(2). That is, he participated in counterinsurgency operations in Southwest Asia with the 11th Marine Expeditionary Unit (MEU). He was part of Operation Desert Shield and Operation Desert Storm. He also served in the waters of the Persian Gulf during this time period aboard the USS New Orleans (LPH-11). With regard to the Persian Gulf presumption, "gastrointestinal signs or symptoms" are listed among the possible manifestations of an undiagnosed illness or medically unexplained chronic multi-symptom illness (MUCMI) for purposes of presumptive service connection. 38 U.S.C. § 1117(g)(10); 38 C.F.R. § 3.317(b)(10). Further, lay persons such as the Veteran are competent to report objective signs of illness such as gastrointestinal pain. 38 C.F.R. § 3.317(a)(3); Gutierrez v. Principi, 19 Vet. App. 1, 9-10 (2004). Most importantly, there is probative medical evidence of record indicating that the Veteran's disability pattern for his lower stomach / intestinal problems is an "undiagnosed illness," with objective indications of a qualifying chronic disability present. See 38 C.F.R. § 3.317(a)(1) and (a)(2)(i)(A) and (a)(3). Specifically, VA treatment records since 2015 have documented constipation and intestinal discomfort and melena. The Veteran was prescribed Docusate to treat his lower stomach signs and symptoms. Most importantly, a January 2022 VA intestinal conditions examiner assessed "episodes of bowel disturbance with abdominal distress." No specific intestinal condition was diagnosed. Rather, the VA examiner concluded that the Veteran's disability pattern to the low stomach was an "undiagnosed illness." The VA examiner added the Veteran's lower stomach condition was presumed to be caused by service in the Southwest Asia theater of operations. In a January 2022 VA medical opinion, the VA examiner added that VA statutes and regulations provide for service connecting certain chronic disability patterns based on exposure to environmental hazards experienced during military service in Southwest Asia, such as the Veteran's lower stomach condition. With regard to the Persian Gulf presumption, given the Veteran's credible complaints regarding episodic constipation, bowel disturbance, and intestinal distress for many years, he clearly has exhibited intermittent periods of improvement and worsening for over six months. See 38 C.F.R. § 3.317(a)(4). Moreover, the Veteran's "episodes of bowel disturbance with abdominal distress" cannot be attributed to any known clinical diagnosis by history, physical examination, or laboratory test. 38 C.F.R. § 3.317(a)(1)(ii). With regard to the Persian Gulf presumption under 38 C.F.R. § 3.317, the Veteran is not required to provide competent evidence linking a current disability to an event during service. Gutierrez, 19 Vet. App. at 8-9. That is, under 38 U.S.C. § 1117 and 38 C.F.R. § 3.317, the gastrointestinal symptom, which is capable of lay observation, is presumed to be related to service, and unlike a claim of "direct service connection," VA cannot impose a medical nexus requirement. Id. at 9-10. Finally, with regard to the Persian Gulf presumption, in order to grant service connection under 38 C.F.R. § 3.317, the Board must determine whether the Veteran's "episodes of bowel disturbance with abdominal distress" is manifest to a degree of 10 percent or more no later than December 31, 2026. See 38 C.F.R. § 3.317(a)(1)(i). As noted above, to determine whether the undiagnosed illness is manifested to a degree of 10 percent or more the condition must be rated by analogy to a disease or injury in which the functions affected, anatomical location or symptomatology are similar. See 38 C.F.R. § 3.317(a)(5); see also Stankevich, 19 Vet. App. at 472. The Board must explain its selection of an analogous Diagnostic Code. Id. In this regard, the Board finds that the Veteran's "episodes of bowel disturbance with abdominal distress" can be rated as at least 10 percent disabling by analogy to Diagnostic Code 7319 for irritable colon syndrome. See 38 C.F.R. § 4.114 (2021). That is, under Diagnostic Code 7319, absent the use of Docusate stool softener, the Veteran's lower stomach condition would manifest in "frequent episodes of bowel disturbance with abdominal distress" that are "moderate" in severity. See Jones v. Shinseki, 26 Vet. App. 56, 63 (2012) (a higher rating may not be denied on the basis of relief provided by medication when those effects are not specifically contemplated by the rating criteria). The functions affected, anatomical location, and symptomatology for Diagnostic Code 7319 is similar to the Veteran's current "episodes of bowel disturbance with abdominal distress." See 38 C.F.R. § 3.317(a)(5); see also Stankevich, 19 Vet. App. at 472. In its selection of an appropriate analogous diagnostic code for the Persian Gulf disability at issue, the Board has also considered the favorable provisions of the VA Adjudication Procedures Manual. See M21-1, VIII.ii.1.C.2.a-c. (July 20, 2022). In summary, since the Veteran here exhibits objective indications of a qualifying chronic disability (bowel disturbance with abdominal distress / an intestinal condition) due to an "undiagnosed illness," manifest to a degree of 10 percent or more prior to December 31, 2026, service connection is warranted here under the Persian Gulf presumption. See 38 C.F.R. § 3.317(a). Accordingly, resolving doubt in the Veteran's favor, the evidence supports service connection for a bowel disturbance with abdominal distress (an intestinal condition) as a qualifying chronic disability under 38 C.F.R. § 3.317. See 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102. This claim is granted. E. Type II Diabetes Mellitus The Veteran contends that his type II diabetes mellitus resulted from his exposure to various toxic chemical and environmental hazards during his service in Southwest Asia (Saudi Arabia and Kuwait) in 1990 and 1991. The Veteran reports that he was first diagnosed with type II diabetes mellitus in 2000. Upon review of the evidence, service connection for type II diabetes mellitus as a qualifying chronic disability under 38 C.F.R. § 3.317 is granted. With regard to the Persian Gulf presumption, as already discussed above, STRs and SPRs and a recent January 2023 VA Memorandum confirm that the Veteran served in the Southwest Asia theater of operations (Saudi Arabia and Kuwait) from December 1990 to August 1991, for purposes of establishing the veteran's status as a "Persian Gulf veteran." 38 C.F.R. § 3.317(e)(1)(2). With regard to the Persian Gulf presumption, "fatigue" is listed among the possible manifestations of an undiagnosed illness or medically unexplained chronic multi-symptom illness (MUCMI) for purposes of presumptive service connection. 38 U.S.C. § 1117(g)(1); 38 C.F.R. § 3.317(b)(1). Further, lay persons such as the Veteran are competent to report objective signs of illness such as fatigue. 38 C.F.R. § 3.317(a)(3); Gutierrez v. Principi, 19 Vet. App. 1, 9-10 (2004). Most importantly, there is probative medical evidence of record indicating that the Veteran's disability pattern for his type II diabetes mellitus is an a diagnosable but "medically unexplained chronic multisymptom illness" (MUCMI) without a conclusive etiology, with objective indications of a qualifying chronic disability present. See 38 C.F.R. § 3.317(a)(1) and (a)(2)(i)(B) and (a)(3). For VA purposes, the term "medically unexplained chronic multisymptom illness" (MUCMI) means a diagnosed illness without conclusive pathophysiology or etiology, that is characterized by overlapping symptoms and signs and has features such as fatigue, pain, disability out of proportion to physical findings, and inconsistent demonstration of laboratory abnormalities. 38 C.F.R. § 3.317(a)(2)(ii); Stewart, 30 Vet. App. at 390. Specifically, a February 2012 Rockford Health System treatment record noted that type II diabetes mellitus was diagnosed in 2011. Similarly, VA treatment records since 2011 have documented type II diabetes mellitus. The Veteran has been prescribed oral hypoglycemic agents to control his diabetes. Most importantly, a January 2022 VA Gulf War Examination assessed that "no etiology" is established for the Veteran's type II diabetes mellitus. Rather, the VA examiner concluded that the Veteran's disability pattern was "a diagnosable but medically unexplained chronic multi-symptom illness of unknown etiology." The VA examiner added the Veteran's type II diabetes mellitus was presumed to be caused by service in the Southwest Asia theater of operations. The same VA examiner in a separate January 2022 VA diabetes mellitus examination repeated the same favorable conclusion. The VA examiner observed that the Veteran exhibited A1C of 6.5% or greater on 2 or more occasions and there was also some abnormal bloodwork. As such, although it appears the pathophysiology for type II diabetes mellitus is revealed through diagnostic testing, the etiology of his type II diabetes mellitus remains inconclusive. See again 38 C.F.R. § 3.317(a)(2)(ii); Stewart, 30 Vet. App. at 390. The Board acknowledges 38 C.F.R. § 3.317(a)(2)(ii) also provides that chronic multisymptom illnesses of partially understood etiology and pathophysiology, such as diabetes and multiple sclerosis, will not be considered medically unexplained for purposes of awarding service connection under the Persian Gulf presumption. However, in the present case, the January 2022 VA examiner determined that the etiology of this particular Veteran's type II diabetes mellitus was unknown, rather than partially understood. In light of the VA examiner's favorable January 2022 medical opinion, which is inconsistent with the language of the relevant VA regulation, the AOJ subsequently directed the VA examiner to address the known causes of diabetes to include possible obesity / weight gain, inactivity, family history, race or ethnicity, age and high blood pressure, which are all known contributors / causes of diabetes, when addressing whether this particular Veteran's diabetes has no known origin. Thereafter, a February 2022 VA addendum opinion on diabetes mellitus indicated there was no nexus to service, based on the lack of a diagnosis for type II diabetes mellitus during active duty. However, the February 2022 VA addendum opinion failed to address any possible causes / etiologies of the diabetes in the Veteran's case, as instructed by the AOJ. Thus, the February 2022 VA addendum opinion was inadequate for failing to address the specific facts of the Veteran's case. See e.g., Bailey v. O'Rourke, 30 Vet. App. 54, 60 (2018). See also Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 305 (2008) (a lack of a reasoned medical explanation is a significant factor in assessing the value of a medical opinion). That notwithstanding, the Board will not remand for additional development as the present record is sufficient to grant service connection for type II diabetes mellitus. Andrews (David) v. McDonough, 34 Vet. App. 216 (2021). Stated another way, VA may not order additional development for the sole purpose of obtaining evidence unfavorable to a claimant. Mariano v. Principi, 17 Vet. App. 305, 312 (2003). See also 38 C.F.R. § 3.304(c) (the development of evidence in connection with claims for service connection will be accomplished when deemed necessary but it should not be undertaken when evidence present is sufficient for this determination). The issue was previously remanded in July 2019. The Board declines to remand this matter any further and will determine entitlement based on the totality of the evidence on the record. With regard to the Persian Gulf presumption, given the clinical evidence of record revealing treatment for type II diabetes mellitus since at least 2011, the Veteran clearly has exhibited intermittent periods of improvement and worsening for over six months. See 38 C.F.R. § 3.317(a)(4). With regard to the Persian Gulf presumption under 38 C.F.R. § 3.317, the Veteran is not required to provide competent evidence linking a current disability to an event during service. Gutierrez, 19 Vet. App. at 8-9. That is, under 38 U.S.C. § 1117 and 38 C.F.R. § 3.317, persistent fatigue due to diabetes, which is capable of lay observation, is presumed to be related to service, and unlike a claim of "direct service connection," VA cannot impose a medical nexus requirement. Id. at 9-10. Finally, with regard to the Persian Gulf presumption, in order to grant service connection under 38 C.F.R. § 3.317, the Board must determine whether the Veteran's type II diabetes mellitus is manifest to a degree of 10 percent or more no later than December 31, 2026. See 38 C.F.R. § 3.317(a)(1)(i). As noted above, to determine whether the undiagnosed illness is manifested to a degree of 10 percent or more the condition must be rated by analogy to a disease or injury in which the functions affected, anatomical location or symptomatology are similar. See 38 C.F.R. § 3.317(a)(5); see also Stankevich, 19 Vet. App. at 472. The Board must explain its selection of an analogous Diagnostic Code. Id. In this regard, the Board finds that the Veteran's type II diabetes mellitus is rated under Diagnostic Code 7913 for diabetes mellitus. See 38 C.F.R. § 4.119 (2021). That is, under Diagnostic Code 7913, a rating of 10 percent is assigned for diabetes mellitus that is managed by a restricted diet only. Id. A rating of 20 percent is assigned for diabetes mellitus requiring one or more daily injection of insulin and a restricted diet or an oral hypoglycemic agent and a restricted diet. Id. In the present case, the Veteran's diabetes would clearly meet the criteria for at least a 10 percent rating, as he is on a restricted diet and is prescribed a hypoglycemic agent to control his type II diabetes mellitus. In summary, there is probative medical evidence of record indicating that the Veteran's disability pattern for his type II diabetes mellitus is an a diagnosable but "medically unexplained chronic multisymptom illness" (MUCMI) without a conclusive etiology, with objective indications of a qualifying chronic disability present. His diabetes is also manifest to a degree of 10 percent or more prior to December 31, 2026. Thus, service-connection is warranted here for type II diabetes mellitus under the Persian Gulf presumption. See 38 C.F.R. § 3.317(a). Accordingly, resolving doubt in the Veteran's favor, the evidence supports service connection for type II diabetes mellitus as a qualifying chronic disability under 38 C.F.R. § 3.317. See 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102. This claim is granted. F. Hyperlipidemia with Angina The Veteran contends that he first experienced chest pain (angina) during active duty from 1988 to 1992, and that he continues to experience periodic chest pain (angina) at the present time, especially during periods of emotional stress. Upon review of the evidence, service connection for hyperlipidemia (high cholesterol) with angina (chest pain) is granted. Dyslipidemia is defined as an "abnormality in, or abnormal amounts of, lipids and lipoproteins in the blood," also referred to as hyperlipidemia. See Dorland's Illustrated Medical Dictionary 586 (31st ed. 2012). Hyperlipidemia is a "general term for elevated concentrations of any or all of the lipids in the plasm," and is a form of dyslipidemia. Id. at 903. High cholesterol is also referred to as hypercholesterolemia or hyperlipidemia. Hypercholesterolemia is an "excess of cholesterol in the blood." Dorland's Illustrated Medical Dictionary 792 (28th ed. 1994). The Board notes its reliance on a medical dictionary to define a term is not in error. See O'Bryan v. McDonald, 771 F.3d 1376, 1380 (Fed. Cir. 2014). During his period of active duty, a March 1989 STR urinalysis and blood test revealed high cholesterol at 245 mg/dl. STRs dated from 1988 to 1992 also reveal multiple complaints of chest pain, chest pressure, and chest tightness, but this chest pain was attributed to causes other than the heart e.g., an egg allergy, a respiratory early pneumonia infection, a flu shot reaction, and a bronchospasm. Moreover, an in-service November 1989 STR chest X-ray was normal for the heart. Post-service, VA treatment records dated from 2011 to 2022 continued to reveal a diagnosis of hyperlipidemia (high cholesterol). The Veteran had a history of hyperlipidemia noted prior to 2011 as well. In this regard, private treatment records from Pain Management and Rehabilitation Center dated from 2010 to 2012 also documented hyperlipidemia (rule out CAD). The Veteran has been on statin therapy with fair control of his hyperlipidemia. The specific medications were Zocor (simvastatin) and Pravastatin. Diet and exercise were recommended to the Veteran to help with his hyperlipidemia. He was told to avoid sweets and educated on the benefits of a low-fat diet by cutting back on red meats and fried foods. He was advised to limit his calorie and salt intake. On several occasions "poor lipid control" was documented and the Veteran was placed on a "lipid profile." Post-service, at a January 2022 VA heart examination, the diagnosis rendered was hyperlipidemia (high cholesterol) with stable angina (chest pain). The etiology given for the stable angina (chest pain) was that the heart works harder during times of stress and activity, which could lead to stable angina (chest pain). In summary, it is undisputed the Veteran has a diagnosis of hyperlipidemia (high cholesterol) and chest pain both in-service and post-service. See 38 C.F.R. 3.303(a). However, the outcome of the hyperlipidemia issue on appeal depends on whether hyperlipidemia or elevated cholesterol with angina (chest pain) constitutes an actual "disability" for VA purposes. In this vein, with regard to the existence of a current disability, Congress specifically limits entitlement for service-connected disease or injury to cases where such incidents have resulted in a disability. The existence of a current disability is the cornerstone of a claim for VA disability compensation. See 38 U.S.C. § 1110; 38 C.F.R. § 3.303(a); Degmetich v. Brown, 104 F. 3d 1328, 1332 (1997). In the absence of proof of a current disability, there can be no valid claim. Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000); Brammer v. Derwinski, 3 Vet. App. 223, 225 (1992). The Board acknowledges that in the past VA previously determined that hyperlipidemia is a laboratory finding and is not a disability in and of itself for which VA compensation benefits is payable. See 61 Fed. Reg. 20440, 20445 (May 7, 1996) ("Diagnoses of hyperlipidemia, elevated triglycerides, and elevated cholesterol are actually laboratory results and are not, in and of themselves, disabilities. They are, therefore, not appropriate entities for the rating schedule."). That is, VA's rating schedule does not list "dyslipidemia" or "hyperlipidemia" or "elevated cholesterol" among ratable disabilities. Marcelino v. Shinseki, 29 Vet. App. 155, 158 (2018) (holding that exclusion of a disorder from the rating schedule is an indication that the condition is not a disability). Therefore, in the past, it is clear hyperlipidemia would automatically not be considered a disability for purposes of VA compensation. However, more recently, the Federal Circuit Court provided a more definitive answer as to what constitutes a "disability" under VA law. The Federal Circuit held that where pain causes functional impairment, a "disability" for VA compensation purposes can exist, even if there is no underlying diagnosis or pathology. Saunders v. Wilkie, 886 F.3d 1356, 1367-68 (Fed. Cir. 2018). The Federal Circuit in Saunders explained that a "disability" under 38 U.S.C. § 1110 refers to the functional impairment in earning capacity, not the underlying cause of said disability. Id. at 1363. Thus, "pain alone can serve as a functional impairment and therefore qualify as a disability." Id. While the Saunders case focused exclusively on pain unattributed to a diagnosis or an identifiable underlying malady or condition, the same reasoning could apply to a laboratory finding or blood or urine test, unrelated to a diagnosed condition. The Court's holding in Saunders is supported by the public policy behind veterans' compensation i.e., to compensate veterans whose ability to earn a living is impaired as a result of their military service. Id. The Saunders holding is also supported by VA regulation - 38 C.F.R. § 4.1 (the term disability is described in terms of "the average impairment in earning capacity resulting from such diseases and injuries and their residual conditions in civil occupations"). See also Davis v. Principi, 276 F.3d 1341, 1345 (Fed. Cir. 2002) (citing with approval VA's definition of "disability" in 38 C.F.R. § 4.1). Subsequently, the Court and Federal Circuit have clarified that the Saunders case is not only limited to pain within an orthopedic context. Rather, the definition of "disability" under 38 U.S.C. § 1110 (and by implication under 38 U.S.C. § 1131) includes any "condition" that results in "functional impairment of earning capacity," for conditions not listed in VA's rating schedule. Martinez-Bodon v. Wilkie, 32 Vet. App. 393, 398 (2020), aff'd sub nom. Martinez-Bodon v. McDonough, 28 F.4th 1241 (Fed. Cir. 2022). In Larson v. McDonough, 10 F.4th 1325, 1329 (Fed. Cir. 2021), the Federal Circuit explained that "Saunders articulated a definition of 'disability' for § 1110 purposes that is distinct from and not coextensive with disabilities listed on the rating schedule." That is, the question raised in Saunders is whether conditions not listed in the Rating Schedule may still be considered for service connection purposes under § 1110 (or § 1131). Id. The Court has added that VA must make a factual determination as to whether a veteran's symptoms or manifestations rise to the level of a "functional impairment in earning capacity." In determining whether a veteran's impairment rises to a level affecting earning capacity, VA can consider manifestations of similar severity, frequency, and duration as those VA has determined by regulation would cause impaired earning capacity in an average person. Wait v. Wilkie, 33 Vet. App. 8, 17 (2020). The Rating Schedule including the individual diagnostic codes may serve as a guide to determine whether certain symptoms may impair earning capacity; however, the Rating Schedule is not dispositive. Id. at 16. Specifically, where VA has determined by regulation that the average person with certain manifestations would suffer an impairment in earning capacity, that may be relevant with regard to whether an individual veteran with similar manifestations has a functional impairment of earning capacity. Id. In short, according to Saunders and its latter progeny cases, the mere fact of a veteran reporting subjective symptoms, whether pain or otherwise, does not necessarily warrant a finding that he or she has met the current disability requirement for VA compensation purposes. Rather, pain (or other symptoms or manifestations) must amount to a current "functional impairment of earning capacity" in order to meet the standard of a current disability. 886 F.3d at 1367. Where the record contains only subjective complaints of pain or other reported symptoms and functional loss, but a clinical examiner and the Board find no evidence showing pain or other reported symptoms that reaches the level of functional impairment of earning capacity, there is no disability for service connection under Saunders and its progeny cases. In the present case, however, there is probative evidence of record that supports the existence of a current disability due to the Veteran's hyperlipidemia (high cholesterol with angina (chest pain). 38 U.S.C. § 1110; 38 C.F.R. § 3.303; Saunders, 886 F.3d 1363-68. Specifically, VA treatment records dated from 2011 to 2022 confirm that the Veteran frequently must adhere to a restricted diet and exercise to control his high cholesterol. Also, VA treatment records dated from 2011 to 2021 recorded that the Veteran had to begin taking the medications Zocor (simvastatin) and Pravastatin on a daily basis to control his hyperlipidemia and keep his cholesterol levels low. The Court has held that a disability rating may not be denied on the basis of relief provided by medications whose impact is not specifically contemplated by the rating criteria. Jones v. Shinseki, 26 Vet. App. 56, 63 (2012). Moreover, the January 2022 VA heart examination and medical opinion assessed that stable angina is chest pain or discomfort that most often occurs with activity or emotional stress. This VA examiner explained that the Veteran has a history of hypertension and hyperlipidemia (high cholesterol), which can decrease blood flow through the blood vessels, in turn making him susceptible to stable angina (chest pain). The VA examiner explained further that hyperlipidemia is where the blood has too many lipids or fats. Too many lipids or fats (hyperlipidemia) within the arteries can create blockages. These blockages make it difficult for blood to flow around which causes the heart to strain harder to pump blood throughout the body, causing angina (chest pain). Thus, the January 2022 VA heart examiner in essence opined that the Veteran's hyperlipidemia (high cholesterol) decreases blood flow through the blood vessels, which makes him susceptible to stable angina (chest pain). In addition, the January 2022 VA interview based METs test for the heart revealed breathlessness at a certain point - for METS 5-7 - one flight of stairs, golfing (without cart), mowing lawn (push mower), heavy yard work (digging). This could constitute a degree of functional impairment in earning capacity from hyperlipidemia. Saunders, 886 F.3d at 1367-68. Here, VA's Rating Schedule does not list "hyperlipidemia" or "elevated cholesterol" or "angina" as a separately ratable disability. However, under 38 C.F.R. § 4.104 (Schedule of Ratings for the Cardiovascular System), both angina and breathlessness were listed in the rating criteria as potential symptoms for numerous cardiovascular disabilities. Once again, the Rating Schedule including the individual diagnostic codes may serve as a guide to determine whether certain symptoms may impair earning capacity. Wait, 33 Vet. App. at 16. Specifically, where VA has determined by regulation that the average person with certain manifestations would suffer an impairment in earning capacity under the Rating Schedule, that may be relevant with regard to whether an individual veteran with similar manifestations has a functional impairment of earning capacity. Id. This is the case here with the Veteran's clinically documented angina and breathlessness due to hyperlipidemia (high cholesterol). Moreover, it is likely that without the ameliorative effects of the Veteran's prescribed daily medications Zocor (simvastatin) and Pravastatin to control his cholesterol level, the Veteran would certainly experience a greater degree of functional impairment of earning capacity from his hyperlipidemia with angina. Id. Accordingly, service connection for hyperlipidemia (high cholesterol) with angina (chest pain) is granted, as all three elements of service connection are met, including the existence of a current disability. 38 U.S.C. § 5107(b); 38 C.F.R. §§ 3.102, 3.303; Lynch, 21 F.4th at 781-82; Saunders, 886 F.3d 1363-68. III. Secondary Service Connection (SSC) When determining service connection, all theories of entitlement, direct and secondary, must be considered if raised by the evidence of record, applying all relevant laws and regulations. Szemraj v. Principi, 357 F.3d 1370, 1371 (Fed. Cir. 2004). A disability can be service connected on a secondary basis if it is proximately due to or the result of a service-connected condition. 38 C.F.R. § 3.310(a). To be service connected on a secondary basis under a causation theory, the primary disability need not be service connected, or even diagnosed, at the time the secondary condition is incurred. Frost v. Shulkin, 29 Vet. App. 131, 138 (2017) (holding that there was not a temporal requirement inherent in 38 C.F.R. § 3.310(a) for claims for service connection on a secondary basis). The Federal Circuit Court recently clarified that a secondary condition is considered service connected if it is "proximately due to or the result of" a service-connected disability per 38 C.F.R. § 3.310(a). However, "direct causation" between the service-connected disability and the claimed condition on appeal is not required (as this would be a higher standard). Long v. McDonough, 38 F.4th 1063, 1065 (Fed. Cir. 2022). Moreover, secondary service connection may also be established, by any increase in severity (i.e., aggravation) of a nonservice-connected condition that is proximately due to or the result of a service-connected condition. 38 C.F.R. § 3.310(b). See also Allen v. Brown, 7 Vet. App. 439, 448 (1995). Where a service-connected disability aggravates a nonservice-connected condition, a veteran may be compensated for the degree of disability (but only that degree) over and above the degree of disability existing prior to the aggravation. Allen, 7 Vet. App. at 448. On March 8, 2023, the Federal Circuit Court most recently held that under the causation standard of 38 U.S.C. § 1110, secondary service connection is warranted where a nonservice-connected disability would have been less severe but-for a service-connected disability, either because there is an etiological link (to include worsening of functionality of the nonservice-connected disability) between the two, or because the service-connected disability resulted in the inability to treat the nonservice-connected disability. Spicer v. McDonough, No. 2022-1239, 2023 U.S. App. LEXIS 5470 (Fed. Cir. Mar. 8, 2023). In the Spicer case, the veteran's service-connected leukemia prevented him from undergoing surgery that would have alleviated functional impairment caused by his nonservice-connected legs, for which the Veteran sought compensation. Id. Stated another way, § 1110 provides for compensation for a worsening of functionalitywhether through an inability to treat or a more direct, etiological cause. Id. This applies to the natural progression of a condition not caused by a service-connected injury or disease, but that nonetheless would have been less severe were it not for the service-connected disability. Id. The Spicer case thus takes a broader view of what constitutes secondary service connection, as opposed to a limited view. A VA medical opinion regarding both the causation and aggravation facets of a secondary service connection claim must be provided in a secondary service connection claim. See El-Amin v. Shinseki, 26 Vet. App. 136, 140-41 (2013) (findings of "not due to," "not caused by," and "not related to" a service-connected disability are insufficient to address the question of aggravation under § 3.310(b)). Moreover, when addressing secondary service connection, a VA medical opinion should not combine the concepts of causation and aggravation; separate, independent findings and rationale should be provided for each one. Atencio v. O'Rourke, 30 Vet. App. 74, 90-91 (2018). In short, in order to establish entitlement to service connection on this secondary basis, there must be (1) evidence of a current disability; (2) evidence of a service-connected disability; and (3) probative evidence establishing a nexus (i.e., link) between the service-connected disability and the current disability. Wallin v. West, 11 Vet. App. 509, 512 (1998). In determining whether secondary service connection is warranted, the Board shall consider the benefit-of-the-doubt doctrine. 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102; Alemany v. Brown, 9 Vet. App. 518 (1996); Gilbert v. Derwinski, 1 Vet. App. 49 (1991). A. Hypertension Upon review of the evidence, service connection for hypertension as secondary to now service-connected hyperlipidemia (high cholesterol) with angina (chest pain) is granted. At the outset, as discussed above, in the present Board decision, the Board has already service-connected the Veteran for the underlying primary disability - hyperlipidemia (high cholesterol) with angina (chest pain). The only remaining question in the present case is whether a secondary relationship exists between the Veteran's current hypertension and his primary service-connected hyperlipidemia (high cholesterol) with angina (chest pain). There is probative medical evidence of record establishing that the Veteran has hypertension that is proximately due to or the result of his now service-connected hyperlipidemia (high cholesterol) with angina (chest pain). 38 C.F.R. § 3.310(a); Atencio, 30 Vet. App. at 90-91. In this regard, the Veteran was first diagnosed with hypertension in the early 2000s according to VA treatment records and according to November 2015 and January 2022 VA hypertension examinations. The Veteran controls his hypertension with Lisinopril. His current hypertension was therefore diagnosed many years subsequent to the in-service hyperlipidemia diagnosis. But more importantly, a January 2022 VA hypertension examination and medical opinion explained that the Veteran has hyperlipidemia (high cholesterol), where the blood has too many lipids or fats. Too many lipids or fats within the arteries can create blockages. In turn, these blockages make it difficult for blood to flow around, which causes the heart to strain harder to pump blood throughout the body. As a result of this strain on the heart, the Veteran's blood pressure becomes high (i.e., hypertension occurs). The Board finds that this VA opinion establishes a secondary relationship between the two disabilities (hyperlipidemia and hypertension). The January 2022 VA hypertension examiner also opined that the Veteran's obesity (a nonservice-connected condition) can also have an impact on his hypertension / blood pressure through overactivation of the sympathetic nervous system, stimulation of the renin-angiotensin-aldosterone system and alteration in adipose derived cytokines, insulin resistance, and structural and functional renal changes. As such, the VA examiner assessed that both the Veteran's service-connected hyperlipidemia and his nonservice-connected obesity contributed to the onset of his hypertension. Regardless, "direct causation" between the Veteran's service-connected hyperlipidemia and his current hypertension is not required under VA law, as this would be a higher standard. See again Long, 38 F.4th at 1065. A veteran need not prove that a disability was "completely" (i.e., totally) caused by a service-connected disability to prevail on a secondary service connection claim. Rather, "proximate cause" need only be demonstrated. "Proximate cause" is defined as "[a] cause that directly produces an event and without which the event would not have occurred." See Donnellan v. Shinseki, 24 Vet. App. 167, 173 (2010) (citing Black's Law Dictionary 213 (7th ed. 1999)). When there are potentially multiple causes of a harm, an action is considered to be a proximate cause of the harm if it is a substantial factor in bringing about the harm and the harm would not have occurred but for the action. Shyface v. Sec'y of Health & Human Svs., 165 F.3d 1344, 1352 (Fed. Cir. 1999) (citing RESTATEMENT (SECOND) OF TORTS §§ 430 cmt. d. and 433 cmt. d. (1965)). A determination of proximate cause is basically one of fact, for determination by adjudication personnel. See VAOPGCPREC 6-2003 (October 28, 2003) and VAOPGCPREC 19-1997. Here, the January 2022 VA hypertension examination and opinion shows that the Veteran's service-connected hyperlipidemia is a substantial factor or proximate cause of his current hypertension, at least enough to meet VA's legal criteria for secondary service connection. Accordingly, secondary service connection for hypertension is warranted. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.310. This issue is granted. (In implementing this award, the AOJ should award the Veteran secondary service connection for hypertension on the basis that it is the direct result of his service-connected hyperlipidemia (high cholesterol) with angina (chest pain) (as opposed to aggravation)). B. Diabetic Peripheral Neuropathy of the RIGHT and LEFT Lower Extremities Upon review of the evidence, service connection for diabetic peripheral neuropathy of the RIGHT and LEFT lower extremities as secondary to now service-connected type II diabetes mellitus is granted. At the outset, as discussed above, in the present Board decision, the Board has already service-connected the Veteran for the underlying primary disability type II diabetes mellitus. The only remaining question in the present case is whether a secondary relationship exists between the Veteran's current diabetic peripheral neuropathy of the RIGHT and LEFT lower extremities with his primary service-connected type II diabetes mellitus. There is probative medical evidence of record establishing that the Veteran has diabetic peripheral neuropathy of the RIGHT and LEFT lower extremities that is proximately due to, the result of, or a complication of his now service-connected type II diabetes mellitus. 38 C.F.R. § 3.310(a); Atencio, 30 Vet. App. at 90-91. In this regard, it is unclear from the record when the Veteran's diabetic peripheral neuropathy began. But the Board sees that as early as August 2004, a VA preventive medicine risk assessment screening revealed a report of "numbness or tingling in legs." Most importantly, a November 2015 VA diabetes mellitus examiner opined that the Veteran has "mild" diabetic peripheral neuropathy to both lower extremities as a "complication" of his now service-connected type II diabetes mellitus. The diabetic neuropathy condition was described as "a tingling to the 10 toes and a numbing feeling alongside the 1st toe of each foot," which the Veteran has experienced "for years," although "unclear" as to when exactly. The medication gabapentin provides some relief for his diabetic peripheral neuropathy of the lower extremities. In addition, January 2022 VA diabetes mellitus and diabetic sensory-motor peripheral neuropathy examinations and opinions diagnosed the Veteran with diabetic peripheral neuropathy in both lower extremities that is a "direct result" of his now service-connected type II diabetes mellitus. This condition limits his movement due to decreased sensation in the lower extremities (feet) with numbness, resulting in difficulty waking and limiting the amount of time he can stand on his feet. The Board finds that these VA examinations and opinions establish a secondary relationship between the two disabilities (type II diabetes mellitus and diabetic peripheral neuropathy of the lower extremities). Accordingly, secondary service connection for diabetic peripheral neuropathy of the RIGHT and LEFT lower extremities is warranted. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.310. These issues are granted. (In implementing this award, the AOJ should award the Veteran secondary service connection for diabetic peripheral neuropathy of the RIGHT and LEFT lower extremities on the basis that this condition is the direct result or complication of his now service-connected type II diabetes mellitus (as opposed to aggravation)). C. Alcohol Abuse Disorder and Polysubstance Abuse Disorder The Veteran contends that he has an alcohol abuse disorder and a polysubstance abuse disorder (cocaine, heroin, cannabis, and opioids) associated with his service-connected PTSD and major depression. He says he began drinking heavily and smoking cannabis during active duty in order to try to forget his "mental anguish" over the physical assaults and racial harassment by his Marine Corps drill sergeants. His other drug abuse addictions (cocaine, heroin, opioids) began post-service in order to "cope" with the same underlying mental health problems, which deteriorated over time. He believes his alcohol abuse disorder and polysubstance abuse disorder are a form of "self-medication" to treat the stress of his underlying service-connected PTSD and major depression. See February 2016 Statement in Support of Claim for PTSD (VA Form 21-0781); March 2019 and July 2022 Veteran statements; and July 2022 Attorney Brief. Upon review of the evidence, service connection for an alcohol abuse disorder and polysubstance abuse disorder as secondary to now service-connected PTSD and major depressive disorder is granted. At the outset, as discussed above, in the present Board decision, the Board has already service-connected the Veteran for the underlying primary disabilities PTSD and major depressive disorder with associated anxiety, insomnia, and memory loss. The only remaining question in the present case is whether a secondary relationship exists between the Veteran's current alcohol abuse disorder and polysubstance abuse disorder with his primary service-connected PTSD and major depressive disorder. Initially, with respect to claims, as here, filed after October 31, 1990, an injury or disease incurred during active service will not be deemed to have been incurred in the line of duty if the injury or disease was a result of the person's willful misconduct, including abuse of alcohol or drugs. See 38 U.S.C. §§ 105, 1110; 38 C.F.R. §§ 3.1(m), (n), 3.301(d). VA's General Counsel has also confirmed that direct service connection for a disability that is a result of a claimant's abuse of alcohol or drugs is precluded for purposes of all VA benefits for claims filed after October 31, 1990. See VAOPGCPREC 7-99 (June 9, 1999); VAOPGCPREC 2-98 (Feb. 10, 1998). Therefore, in the present case, service connection for any primary alcohol or drug abuse disorder the Veteran has would generally be precluded by law. However, service-connected disability compensation may be awarded for an alcohol or drug abuse disability secondary to a service-connected disability or use of an alcohol or drug abuse disability as evidence of the increased severity of a service-connected disability. Allen v. Principi, 237 F.3d 1368, 1376 (Fed. Cir. 2001). In this regard, the Federal Circuit cautioned that compensation would only result where there was clear medical evidence establishing that the alcohol or drug abuse disability was caused or aggravated by a veteran's primary service-connected disability. Id. Historically, beginning in 1989, the Veteran's STRs document daily alcohol use during his period of active duty from 1988 to 1992. Post-service, according to VA, private, and SSA treatment records, the Veteran has undergone at least four inpatient hospitalizations for alcohol and drug abuse beginning sometime between 1996 and 1999. He began psychiatric counseling and psychiatric medications to control his polysubstance abuse in 1996. He has had six reported DUIs due to excessive alcohol use - 1993, 1995, 2000, 2003, 2006, and 2011. He has been incarcerated on multiple occasions resulting from substance abuse. In the present case, there is probative medical evidence of record establishing that the Veteran has a current alcohol abuse disorder and polysubstance abuse disorder that are proximately due to or the result of his now service-connected PTSD and major depressive disorder. 38 C.F.R. § 3.310(a); Atencio, 30 Vet. App. at 90-91; Allen, 237 F.3d at 1376. In this regard, the Veteran has submitted an April 2011 Drug and Alcohol Review medical treatise research study discussing a relationship between PTSD, depression, and suicidality in individuals with substance abuse disorders requiring inpatient treatment. A December 2013 private psychological evaluation from Psychology Consultants, P.C., documented that the Veteran's alcohol and narcotic abuse was used to "self-medicate." A January 2014 VA mental health telehealth note by a VA psychiatrist advised the Veteran drank an excessive amount of alcohol to deal with his psychiatric anxiety, insomnia, and pain. Finally, a September 2017 private mental disorders DBQ (VA Form 21-0960P-2) by Heather Henderson-Galligan, psychologist, and an accompanying September 2017 private psychological evaluation and opinion from the same psychologist, opined that the Veteran self-medicates with alcohol. She further remarked that traumatic events per medical treatise research are common for Veterans with substance abuse. She added that this Veteran self-medicates his psychiatric problems with substance abuse. The Board concludes that the above clinical evidence establishes a secondary relationship between his alcohol and polysubstance abuse disorders and his now service-connected PTSD with major depression. See again 38 C.F.R. § 3.310(a); Allen, 237 F.3d at 1376. Accordingly, secondary service connection for an alcohol abuse disorder and polysubstance abuse disorder is warranted. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.310; Allen, 237 F.3d at 1376. This claim is granted. (In implementing this award, the AOJ should award the Veteran secondary service connection for an alcohol abuse disorder and polysubstance abuse disorder on the basis that these conditions are the direct result of his now service-connected PTSD and major depressive disorder (as opposed to aggravation)). IV. Increased Ratings Disability ratings are determined by applying the criteria set forth in the VA Schedule for Rating Disabilities, found in 38 C.F.R., Part 4. The Rating Schedule is primarily a guide in the evaluation of disability resulting from all types of diseases and injuries encountered as a result of or incident to military service. The ratings are intended to compensate, as far as can practicably be determined, the average impairment of earning capacity resulting from such diseases and injuries and their residual conditions in civilian occupations. 38 U.S.C. § 1155; 38 C.F.R. § 4.1. Where there is a question as to which of two evaluations shall be applied, the higher evaluation will be assigned if the disability picture more nearly approximates the criteria for that rating. 38 C.F.R. § 4.7. With regard to lay evidence, the Board must also assess the competence and credibility of lay statements and testimony. Barr v. Nicholson, 21 Vet. App. 303, 308 (2007). In increased rating claims, a veteran's lay statements alone, absent a negative credibility determination, may constitute competent evidence of worsening, at least with respect to observable symptoms. See Vazquez-Flores v. Shinseki, 24 Vet. App. 94, 102 (2010), rev'd on other grounds by Vazquez-Flores v. Shinseki, 580 F.3d 1270, 1277 (Fed. Cir. 2009). The Court has held that painful motion, in particular, may be "objectively confirmed" by a layperson who witnessed a veteran experience difficulty walking, standing, or sitting, or display a facial expression, such as wincing, indicative of pain. Petitti v. McDonald, 27 Vet. App. 415, 429-30 (2015). However, the Board can discount lay evidence in its role as factfinder if it weighs the evidence, finds the clinical evidence more probative, and provides an explanation with supporting reasons or bases. English v. Wilkie, 30 Vet. App. 347, 352-53 (2018). When reasonable doubt arises as to the degree of disability, such doubt will be resolved in the Veteran's favor. 38 C.F.R. § 4.3. A. Lumbar Spine at 10% The Veteran is service connected for a lumbosacral strain, rated as 10 percent disabling under Diagnostic Code 5237 (lumbosacral strain). 38 C.F.R. § 4.71a (2021). This 10 percent rating has been in effect since August 26, 2013, the date the Veteran filed his informal claim for service connection. The Veteran has appealed the original December 2015 rating decision that granted service connection for a lumbosacral strain. He has expressed disagreement with the initial 10 percent rating assigned. Thus, this case could result in "staged ratings" based upon the facts found during the period in question. See Hart v. Mansfield, 21 Vet. App. 505, 509-510 (2007); Fenderson v. West, 12 Vet. App. 119, 126 (1999). The relevant time period for consideration in a claim for an increased initial disability rating is the period beginning on the date that the claim for service connection was filed. Moore v. Nicholson, 21 Vet. App. 211, 216-17 (2007). That is to say, the Board must consider whether there have been times since the effective date of his award when his lumbosacral strain has been more severe than at others for the time period from August 26, 2013 to the present. Id. However, the Board is cognizant that 38 C.F.R. §§ 4.1 and 4.2 and 4.41 require VA adjudicators to view each disability "in relation to its history" to "accurately reflect the elements of disability present," respectively. See Jones v. Shinseki, 26 Vet. App. 56, 62 (2012); see also Moore v. Shinseki, 555 F.3d 1369, 1373 (Fed. Cir. 2009) (discussing 38 C.F.R. §§ 4.1 and 4.2 and stating that, although the veteran was "only entitled to disability compensation for the period after ... the date he filed his original claim for benefits," VA regulations still require the disability to be "evaluated in light of its whole recorded history"). Therefore, the Board has also considered and reviewed the Veteran's entire history of his lumbosacral strain symptomatology, when evaluating this disability. 38 C.F.R. § 4.1. The Veteran's current 10 percent rating for his service-connected lumbosacral strain under Diagnostic Code 5237 was assigned based on orthopedic manifestations of his disability under the General Rating Formula for Diseases and Injuries of the Spine. See 38 C.F.R. § 4.71a. The Board is cognizant of the additional changes to the Rating Schedule that addresses the musculoskeletal system and muscle injuries, which are effective February 7, 2021. One such change impacts Diagnostic Code 5242 for degenerative arthritis of the spine. See Schedule for Rating Disabilities: Musculoskeletal System and Muscle Injuries, 85 Fed. Reg. 76453, 76462 (Nov. 30, 2020) (codified at 38 C.F.R. § 4.71a). Specifically, Diagnostic Code 5242 now indicates that degenerative arthritis of the spine includes degenerative disc disease (DDD) other than intervertebral disc syndrome (IVDS). VA has also added an instruction to Diagnostic Code 5243 for IVDS to assign this diagnostic code (DC 5243) only when there is disc herniation with compression and / or irritation of the adjacent nerve root; otherwise, assign Diagnostic Code 5242 for degenerative arthritis for all other diagnoses. Id. In any event, neither Diagnostic Code 5242 nor Diagnostic Code 5243 apply to the facts of this Veteran's case under either the old or new criteria, since no VA or private clinician of record has diagnosed the Veteran with degenerative arthritis, DDD, a disc herniation, or IVDS of the lumbar spine. Nor is there any evidence of compression and / or irritation of the adjacent nerve root (the sciatic nerve) that would impact the Veteran's lower extremities (in terms of causing any sciatic radiculopathy). In short, Diagnostic Code 5237 remains the most appropriate diagnostic code in rating this Veteran's service-connected lumbosacral strain disability. See Butts v. Brown, 5 Vet. App. 532, 538 (1993). The General Rating Formula for Diseases and Injuries of the Spine is as follows: With or without symptoms such as pain (whether or not it radiates), stiffness, or aching in the area of the spine affected by residuals of injury or disease: A 10 percent rating is assigned for forward flexion of the thoracolumbar spine greater than 60 degrees but not greater than 85 degrees; or, combined range of motion of the thoracolumbar spine greater than 120 degrees but not greater than 235 degrees; or, muscle spasm, guarding, or localized tenderness not resulting in abnormal gait or abnormal spinal contour; or, vertebral body fracture with loss of 50 percent or more of the height. A 20 percent rating is assigned for forward flexion of the thoracolumbar spine greater than 30 degrees but not greater than 60 degrees; or, the combined range of motion of the thoracolumbar spine not greater than 120 degrees; or, muscle spasm or guarding severe enough to result in an abnormal gait or abnormal spinal contour such as scoliosis, reversed lordosis, or abnormal kyphosis (emphasis added). A 40 percent rating requires evidence of forward flexion of the thoracolumbar spine to 30 degrees or less; or, favorable ankylosis of the entire thoracolumbar spine. A 50 percent evaluation will be assigned with evidence of unfavorable ankylosis of the entire thoracolumbar spine. A 100 percent rating requires evidence of unfavorable ankylosis of the entire spine. Note (1): Evaluate any associated objective neurologic abnormalities, including, but not limited to, bowel or bladder impairment, separately, under an appropriate diagnostic code. Note (2): (See also Plate V) For VA compensation purposes, normal forward flexion of the thoracolumbar spine is zero to 90 degrees, extension is zero to 30 degrees, left and right lateral flexion is zero to 30 degrees, and left and right lateral rotation is zero to 30 degrees. The combined range of motion refers to the sum of the range of forward flexion, extension, left and right lateral flexion, and left and right rotation. The normal combined range of motion of the thoracolumbar spine is 240 degrees. The normal ranges of motion for each component of spinal motion provided in this note are the maximum that can be used for calculation of the combined range of motion. Note (4): Round each range of motion measurement to the nearest five degrees. Note (5): For VA compensation purposes, unfavorable ankylosis is a condition in which the entire cervical spine, the entire thoracolumbar spine, or the entire spine is fixed in flexion or extension, and the ankylosis results in one or more of the following: difficulty walking because of a limited line of vision; restricted opening of the mouth and chewing; breathing limited to diaphragmatic respiration; gastrointestinal symptoms due to pressure of the costal margin on the abdomen; dyspnea or dysphagia; atlantoaxial or cervical subluxation or dislocation; or neurologic symptoms due to nerve root stretching. Fixation of a spinal segment in neutral position (zero degrees) always represents favorable ankylosis. Note (6): Separately evaluate disability of the thoracolumbar and cervical spine segments, except when there is unfavorable ankylosis of both segments, which will be rated as a single disability. See 38 C.F.R. § 4.71a, Diagnostic Code 5237 (2021). When evaluating musculoskeletal disabilities based on limitation of motion, the Rating Schedule requires consideration of limitation of functional ability or additional range of motion lost during flare-ups or after repetitive motion, but not necessarily reflected on range-of-motion testing at the VA examination. See 38 C.F.R. §§ 4.40, 4.45, 4.59; Sharp v. Shulkin, 29 Vet. App. 26, 33 (2017); Mitchell v. Shinseki, 25 Vet. App. 32, 44 (2011); DeLuca v. Brown, 8 Vet. App. 202, 206 (1995). Also, 38 C.F.R. § 4.45 requires consideration to be given to such factors as less movement than normal, more movement than normal, weakened movement, excess fatigability, incoordination, and pain on movement. Nonetheless, even when the background factors listed in § 4.40 or 4.45 are relevant when evaluating a disability, the rating is assigned based on the extent to which motion is limited, pursuant to 38 C.F.R. § 4.71a (musculoskeletal system) or § 4.73 (muscle injury); a separate or higher rating under § 4.40 or 4.45 itself is not appropriate. See Thompson v. McDonald, 815 F.3d 781, 785 (Fed. Cir. 2016) ("[I]t is clear that the guidance of § 4.40 is intended to be used in understanding the nature of the veteran's disability, after which a rating is determined based on the § 4.71a [or 4.73] criteria."). The Court has held that "limitation of motion" and "painful motion" are distinct concepts, although limitation of motion is a factor that may be considered to determine whether painful motion is present. Tedesco v. Wilkie, 31 Vet. App. 360, 365-66 (2019). Under 38 C.F.R. § 4.59, painful motion is a factor to be considered with any form of arthritis; however, 38 C.F.R. § 4.59 is not limited to disabilities involving arthritis. See Burton v. Shinseki, 25 Vet. App. 1 (2011). Further, 38 C.F.R. § 4.59 requires that "[t]he joints involved should be tested for pain on both active and passive motion, in weight-bearing and nonweight-bearing and, if possible, with the range of the opposite undamaged joint." Correia v. McDonald, 28 Vet. App. 158, 169-170 (2016). The Court has also held that the plain language of § 4.59 is applicable to the evaluation of musculoskeletal disabilities involving joint or periarticular pathology that are painful, whether or not evaluated under a diagnostic code predicated on range of motion measurements. Southall-Norman v. McDonald, 28 Vet. App. 346, 354 (2016). The Court has held that section 4.59 does not apply where the applicable diagnostic codes fail to provide for a compensable rating. Sowers v. McDonald, 27 Vet. App. 472, 480-81 (2016). Upon review, a higher 20 percent rating, but no greater, for the Veteran's lumbosacral strain is granted. 38 C.F.R. § 4.7. In making this determination that a 20 percent rating is warranted, the Board has reviewed both the medical and lay evidence of record. Specifically, there is probative medical and lay evidence of record revealing muscle spasms of the lumbar spine severe enough to result in an abnormal gait at times, when considering the factors of functional loss. See 38 C.F.R. § 4.71a, Diagnostic Code 5237. That is, VA treatment records dated from 2015 to 2017 and from 2019 to 2020 confirm low back muscle spasms and pain, for which the Veteran was prescribed muscle relaxers to control the flare-ups. The April 2018 VA back examiner commented that the Veteran uses a cane "occasionally" to ambulate when his lumbar spine pain is severe. In fact, at times during flare-ups the Veteran has reported that his muscle spasms of his lumbar spine result in him having to use a cane or an electric cart at the grocery store. The Board also points out that 38 C.F.R. § 4.59 specifically notes that "muscle spasm will greatly assist" in identifying painful motion of the spine. In support of a higher 20 percent rating, the Veteran's lay statements of record and lay reported history to VA back examiners is mostly competent, credible, and probative in describing the functional impact of his thoracolumbar spine disability on his activities of daily living and on any potential occupation. See 38 C.F.R. § 3.159(a)(2); Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006) (noting that the Board, as fact finder, is responsible for assessing the credibility, competence, and probative value of evidence). Credible testimony is that which is plausible or capable of being believed. Caluza v. Brown, 7 Vet. App. 498 (1995). In the present case, the Veteran's lay statements are for the most part credible and probative. He describes his low back pain as "severe and constant," especially with activity or movement. Due to his low back, he cannot walk long distances, he cannot stand for more than 5-10 minutes. He cannot find a comfortable position to alleviate his low back pain. Notably, interference with sitting and standing are factors of disability for assigning a higher 20 percent rating for this Veteran's lumbar spine. See 38 C.F.R. § 4.45(f). He experiences low back pain on movement, with lifting, bending, pushing, pulling, mopping, and dusting, thus aggravating his low back. It is difficult to climb stairs, he cannot lift weights, and at times he rides a cart when grocery shopping due to low back pain. To treat his low back, he takes pain medications and uses a low back brace. His low back disability limits the type of work he can do. See July 2022 Veteran statement and July 2022 Attorney Brief. In support of a higher 20 percent rating for the lumbar spine, the Board has noticed that the rating criteria pertaining to the thoracolumbar spine under 38 C.F.R. § 4.71a, Diagnostic Code 5237, do not contemplate the relief provided by the Veteran's various pain medications Tylenol, Ibuprofen, or multiple muscle relaxers (e.g., Flexeril and methocarbamol). Over the course of the appeal from 2013 to 2022, the Veteran has mixed and matched these pain medications when necessary. Therefore, a higher 20 percent rating cannot be denied here on the basis of the relief provided by the Veteran's various pain medications and modalities, as those effects are not specifically contemplated by the rating criteria for the lumbar spine. Jones v. Shinseki, 26 Vet. App. 56, 63 (2012). Simply stated, it is likely that without the ameliorative effects of his various pain medications, the Veteran would certainly experience on a more frequent basis muscle spasms of the lumbar spine severe enough to result in an abnormal gait, indicative of a higher 20 percent rating. See 38 C.F.R. § 4.71a, Diagnostic Code 5243; Jones, 26 Vet. App. at 63. This is especially so especially during flare-ups or after repetitive use of the lumbar spine. See 38 C.F.R. § 4.40; Sharp, 29 Vet. App. at 33; DeLuca, 8 Vet. App. at 206. Thus, the Board has taken the positive effects of his pain medications into account when assigning a higher 20 percent rating for his service-connected lumbosacral strain based on orthopedic manifestations under the General Rating Formula for Diseases and Injuries of the Spine. Resolving all reasonable doubt in his favor, a higher 20 percent rating under Diagnostic Code 5237 is warranted for orthopedic manifestations of the Veteran's lumbosacral strain, with consideration of functional loss and the favorable impact of pain medications on his lumbar spine pain. 38 C.F.R. § 4.3. However, the Board concludes that the Veteran is not entitled to an initial rating in excess of 20 percent for his service-connected lumbosacral strain. 38 C.F.R. § 4.7. In making this determination, the Board has considered both the competent and credible medical and lay evidence of record. With regard to orthopedic manifestations of the Veteran's lumbar spine disability with consideration of functional loss (38 C.F.R. §§ 4.40, 4.45, 4.59), the most probative evidence of record does not reveal "unfavorable ankylosis of the entire spine" warranting a higher 100 percent evaluation, or "unfavorable ankylosis of the entire thoracolumbar spine" warranting a higher 50 percent evaluation, or favorable ankylosis of the entire thoracolumbar spine warranting a higher 40 percent evaluation, or forward flexion of the thoracolumbar spine 30 degrees or less warranting a higher 40 percent evaluation. 38 C.F.R. § 4.71a. On this issue, ankylosis is defined as the "immobility and consolidation" of a joint due to disease, injury, surgical procedure - in essence, complete limitation of motion. Chavis v. McDonough, 34 Vet. App. 1, 13 (2021). See also Steadman's Medical Dictionary 95 (28th ed. 2006) ("Stiffening or fixation of a joint as the result of a disease process, with fibrous or bony union across the joint."); Churchill's Illustrated Medical Dictionary 91 (1989) ("A stiffening or immobilization of a joint as a result of injury, disease, or surgical intervention."). The Federal Circuit Court has held that the Board could consider assigning a rating based on ankylosis where there is functional immobility of the spine during flare-ups, even though there is no clinical assessment of ankylosis in the record. That is, evidence of the functional equivalent of ankylosis during flare-ups, pursuant to 38 C.F.R. § 4.40 and 4.45, colloquially known as the DeLuca factors, can satisfy the criteria for a rating based on ankylosis. Chavis v. McDonough, 34 Vet. App. 1, 20 (2021). Here, range of motion and other clinical findings for the thoracolumbar spine, although limited at times, were not functionally equivalent to unfavorable or favorable ankylosis, even when considering pain and other factors of functional loss and repetition of range of motion x 3 and flare-ups. See again 38 C.F.R. §§ 4.40, 4.45, 4.59; Chavis, 34 Vet. App. at 20-21; Sharp, 29 Vet. App. at 33; DeLuca, 8 Vet. App. at 206. That is, post-service VA and SSA and private treatment records dated from 2013 to 2022 documented low back pain and other low back symptomatology but failed to reveal any evidence of the functional equivalent of thoracolumbar spine "favorable" or "unfavorable" ankylosis. The Veteran was almost always seen ambulating. VA back examinations dated in November 2015, April 2018, and January 2022 specifically assessed no ankylosis for the spine after objective examination. The Veteran's lay statements similarly do not indicate that there has been ankylosis or findings more nearly approximating the functional equivalent of ankylosis. Although the Veteran reported he has to occasionally rest during lumbar spine flare-ups, this is not equivalent to functional immobility of his lumbar spine with complete limitation of motion per the Chavis case. In fact, there are multiple times in the record when the Veteran denied any low back symptoms, and no low back symptoms were elicited upon examination. See e.g., April 2015 VA internal medicine outpatient note; December 2016 VA SATP admission evaluation note; and August 2022 VA general medicine note. The Board has considered the Veteran's need to use a back brace, his medications, his reported constant and severe pain, and other functional impairments that he exhibited or reported for the low back from 2013 to 2022. Nonetheless, there is no evidence in the record establishing that the entire thoracolumbar spine, or the entire spine, is fixed in flexion or extension. See Note (5) to the General Rating Formula for Diseases and Injuries of the Spine (defining "unfavorable" ankylosis for VA purposes). In addition, with or without medication, there is no evidence of any of the signs of unfavorable ankylosis, such as difficulty walking because of a limited line of vision; restricted opening of the mouth and chewing; breathing limited to diaphragmatic respiration; gastrointestinal symptoms due to pressure of the costal margin on the abdomen; dyspnea or dysphagia; atlantoaxial or cervical subluxation or dislocation; or neurologic symptoms due to nerve root stretching. Id. Also, there is no evidence in the record establishing that fixation of the thoracolumbar spinal segment in neutral position (zero degrees). See Note (5) to the General Rating Formula for Diseases and Injuries of the Spine (defining "favorable" ankylosis for VA purposes). In addition, for range of motion, the Veteran has not been shown to have forward flexion of the thoracolumbar spine to 30 degrees or less, which is necessary for a higher 40 percent rating under Diagnostic Code 5237. See 38 C.F.R. § 4.71a, General Rating Formula for Diseases and Injuries of the Spine. That is, even when considering pain and other factors of functional loss and repetition of range of motion x 3 and flare-ups, the Veteran does not meet the criteria for a higher 40 percent rating, as he did not exhibit thoracolumbar flexion limited to 30 degrees or less during the appeal. See again 38 C.F.R. §§ 4.40, 4.45, 4.59; Sharp, 29 Vet. App. at 33; DeLuca, 8 Vet. App. at 206. Specifically, at worst, when considering the impact of pain and other factors of functional loss, the November 2015 VA back examination showed that his forward flexion of the thoracolumbar spine was limited to 90 degrees. A December 2016 VA SATP admission evaluation note showed normal range of motion of the joints. The April 2018 VA back examination showed that his forward flexion of the thoracolumbar spine was limited to 80 degrees. And the January 2022 VA back examination showed that his forward flexion of the thoracolumbar spine was limited to 70 degrees. With regard to incapacitating episodes, the Formula for Rating IVDS Based on Incapacitating Episodes provides that a higher 40 percent rating would require evidence of incapacitating episodes having a total duration of at least 4 weeks but less than 6 weeks during the past 12 months. Note (1) indicates that for purposes of evaluations under Diagnostic Code 5243, an incapacitating episode is a period of acute signs and symptoms due to IVDS that requires bed rest prescribed by a physician and treatment by a physician. Note (2) indicates that if IVDS is present in more than one spinal segment, provided that the effects in each spinal segment are clearly distinct, each segment will be evaluated on the basis of incapacitating episodes or under the General Rating Formula for Diseases and Injuries of the Spine, whichever method results in a higher evaluation for that segment. 38 C.F.R. § 4.71a, Diagnostic Code 5243 (2021). Regardless, with regard to incapacitating episodes, although the Veteran has provided some lay descriptions of the necessity for bed rest when his lumbar spine flares up, no VA, SSA, or private clinician of record has diagnosed the Veteran with IVDS of the thoracolumbar spine under Diagnostic Code 5243. In fact, the November 2015, April 2018, and January 2022 VA back examiners specifically assessed no IVDS for the thoracolumbar spine after objective examination. And as already mentioned above, there is no diagnosis in the record for lumbar spine DDD or lumbar spine disc herniation or even lumbar spine arthritis. As such, the Formula for Rating IVDS Based on Incapacitating Episodes cannot apply here. With regard to neurological manifestations of his thoracolumbar spine disability, the Board is aware that under the General Rating Formula for Diseases and Injuries of the Spine, associated objective neurologic abnormalities should be evaluated separately under an appropriate diagnostic code. See 38 C.F.R. § 4.71a, Note (1) (Diagnostic Codes 5235 to 5243). In any event, the medical and lay evidence of record does not demonstrate neuropathy or radiculopathy of the lower extremities associated with his service-connected lumbosacral strain. See 38 C.F.R. §§ 4.120, 4.124a. In this regard, the November 2015 and April 2018 and January 2022 VA back examiners concluded there were no radicular symptoms in the Veteran's lower extremities due to his lumbar spine. The April 2018 VA back examiner conducted neurological testing in making this assessment. In a January 2022 VA medical opinion, the VA back examiner assessed that the Veteran has peripheral neuropathy to his lower extremities caused by his type II diabetes mellitus, but there was no supporting evidence his service-connected lumbosacral strain caused any lower extremity neuropathy. Therefore, the Board concludes that the Veteran does not have any additional neurological deficiency that is a manifestation of his service-connected lumbar spine disability so as to warrant a separate disability rating(s) under the diagnostic codes pertinent to rating neurological disorders. See Bierman v. Brown, 6 Vet. App. at 129-132 (1994). On a side note, the most recent April 2018 and January 2022 VA back examinations included joint testing for pain on both active and passive motion, in weight-bearing and nonweight-bearing and, if possible, with range of motion measurements of the opposite undamaged joint, or in the alternative explained why the Correia requirements would not pertain to the Veteran's particular thoracolumbar spine disability. Correia v. McDonald, 28 Vet. App. 158, 169-70 (2016). Thus, even though the earlier November 2015 VA spine examination of record did not satisfy the requirements of the Correia case, here this is inconsequential and, therefore, at most harmless error. See 38 C.F.R. § 20.1102. His lumbar spine symptoms have been fairly consistent in severity from 2013 to 2022, such that there is no logical reason any of the Correia findings would have differed at the earlier November 2015 VA back examination. On another side note, the April 2018 and January 2022 VA back examinations complied with the holdings of Sharp v. Shulkin, 29 Vet. App. 26 (2017) and Mitchell v. Shinseki, 25 Vet. App. 32 (2011). However, the earlier November 2015 VA back examiner did not properly address and / or estimate the degree of functional loss present during flare-ups or after repeated use of the lumbar spine over time. In any event, the record does not demonstrate that the Veteran's description of his flare-ups or the impact of repeated use of his lumbar spine were significantly worse in 2015 than they were in 2022. The Board has already considered the Veteran's lay description of his functional loss impairments in this case in awarding a higher 20 percent rating for his lumbar spine throughout the entire appeal period. Thus, there is no rational basis for a retrospective medical opinion for past estimates of functional impairment based on the holdings of the Correia and Sharp cases. See Chotta v. Peake, 22 Vet. App. 80 (2008) (when there is an absence of medical evidence during a certain period of time, a retroactive medical evaluation may be warranted). Accordingly, the Board grants a 20 percent initial rating, but no higher, for the Veteran's lumbosacral strain. 38 C.F.R. § 4.3. Finally, for his lumbosacral strain, neither the Veteran nor his attorney has raised any other issues, nor have any other issues been reasonably raised by the record. See Yancy v. McDonald, 27 Vet. App. 484, 495 (2016); Doucette v. Shulkin, 38 Vet. App. 366, 369-70 (2017) (confirming that the Board is not required to address issues unless they are specifically raised by the claimant or reasonably raised by the evidence of record). B. Tension Headaches at 0% and 30% Staged ratings are appropriate when the factual findings show distinct time periods in which a disability exhibits symptoms that warrant different ratings. Hart v. Mansfield, 21 Vet. App. 505, 509-10 (2007); Fenderson v. West, 12 Vet. App. 119, 126 (1999). The relevant time period for consideration in a claim for an initial disability rating is the period beginning on the date that the claim for service connection was filed. Moore v. Nicholson, 21 Vet. App. 211, 216-17 (2007). That is to say, the Board must consider whether there have been times since the effective date of his award when his tension headaches have been more severe than at others for the time period from August 26, 2013 (the day his initial rating claim was filed) to the present. Id. However, the Board is cognizant that 38 C.F.R. §§ 4.1 and 4.2 and 4.41 require VA adjudicators to view each disability "in relation to its history" to "accurately reflect the elements of disability present," respectively. See Jones v. Shinseki, 26 Vet. App. 56, 62 (2012); see also Moore v. Shinseki, 555 F.3d 1369, 1373 (Fed. Cir. 2009) (discussing 38 C.F.R. §§ 4.1 and 4.2 and stating that, although the veteran was "only entitled to disability compensation for the period after ... the date he filed his original claim for benefits," VA regulations still require the disability to be "evaluated in light of its whole recorded history"). Therefore, the Board has also considered and reviewed the Veteran's entire history for his tension headaches, when assigning a disability evaluation in the present case. 38 C.F.R. § 4.1. The Veteran's tension headaches disability is rated under Diagnostic Code 8100 (migraine headaches). 38 C.F.R. § 4.124a (2021). The Veteran's tension headaches disability has been staged by the AOJ at 0 percent and 30 percent for separate periods of time. From August 26, 2013 to April 18, 2018, the Veteran's tension headaches are rated as 0 percent disabling (noncompensable) under Diagnostic Code 8100. From April 18, 2018 to the present, the Veteran's tension headaches are rated as 30 percent disabling under Diagnostic Code 8100. Tension headaches are rated pursuant to 38 C.F.R. § 4.124a, Diagnostic Code 8100, for migraine headaches. Under Diagnostic Code 8100, a noncompensable rating is warranted for migraines with less frequent attacks. A 10 percent rating is warranted for migraines with characteristic prostrating attacks averaging one in 2 months over the last several months. A 30 percent rating is warranted for migraines with characteristic prostrating attacks occurring on an average once a month over the last several months. A 50 percent rating is warranted for migraines with very frequent completely prostrating and prolonged attacks productive of severe economic inadaptability. A 50 percent rating is the highest schedular rating under Diagnostic Code 8100. See 38 C.F.R. § 4.124a (2021). The rating criteria for Diagnostic Code 8100 are considered successive, meaning that a claimant cannot fulfill the criteria of the higher rating without fulfilling those of the next lower rating. Johnson v. Wilkie, 30 Vet. App. 245, 252 (2018). This renders 38 C.F.R. §§ 4.7 and 4.21 inapplicable. Johnson, 30 Vet. App. at 252. The Federal Circuit has held that if disability rating criteria are written in the conjunctive, as they are here, "a Veteran must demonstrate all of the required elements in order to be entitled to that higher evaluation" and 38 C.F.R. § 4.7 cannot be used to circumvent the need to demonstrate all required criteria. Middleton v. Shinseki, 727 F.3d 1172, 1178 (Fed. Cir. 2013). The phrase "characteristic prostrating attacks" is used in the criteria corresponding to 10 percent and 30 percent ratings under Diagnostic Code 8100 to describe the nature and severity of migraines, but it is not defined in the regulation. Pursuant to Dorland's Illustrated Medical Dictionary 1531 (32d ed. 2012), prostration is defined as "extreme exhaustion or powerlessness." Thus, the phrase "characteristic prostrating attacks" is understood to describe migraine attacks that typically produce extreme exhaustion or powerlessness. The VA Adjudication Procedures Manual (M21-1) provides that the term "prostrating," as used in 38 C.F.R. § 4.124a, DC 8100, means "causing extreme exhaustion, powerlessness, debilitation or incapacitation with substantial inability to engage in ordinary activities." See M21-1, V.iii.12.A.3.b. (June 21, 2021). The Board has cited this particular M21-1 provision because it is potentially beneficial to the Veteran's case. See, e.g., Stover v. McDonough, 35 Vet. App. 394 (2022); Andrews v. McDonough, 34 Vet. App. 216, 223 (2021); Wilson v. McDonough, 35 Vet. App. 75, 80 (2021). The rating criteria for the maximum 50 percent rating contains several undefined phrases. The descriptive phrase "very frequent" connotes a frequency at least greater than once a month. Johnson, 30 Vet. App. at 253. The phrase "completely prostrating" in the 50 percent rating criteria generally means that the migraines attack must render the veteran entirely powerless. Id. The M21-1 provides that the term "completely prostrating," as used in 38 C.F.R. § 4.124a, DC 8100, means "extreme exhaustion or powerlessness with essentially total inability to engage in ordinary activities." See M21-1, V.iii.12.A.3.b. (June 21, 2021). The completely prostrating attacks in the 50 percent rating criteria must also be "prolonged," which is defined as "to lengthen in time: extend duration: draw out: continue, protract." Johnson, 30 Vet. App. at 253 (internal citation omitted). The Court in Johnson suggested that headaches "lasting for hours" are the equivalent of the term "prolonged." Id. at 248. The term "severe" in the 50 percent rating criteria generally means "of a great degree" or "serious." See Merriam-Webster's Collegiate Dictionary, 1140 (11th ed. 2003). However, the Board is cognizant of the Court's holding that what is classified as "severe" can be dependent on the diagnostic code used. See Breniser v. Shinseki, 25 Vet. App. 64, 76-77 (2011). Lastly, the 50 percent rating criteria requires that the very frequent completely prostrating and prolonged attacks be "productive of severe economic inadaptability." Productive can be read as having either the meaning of "producing" or "capable of producing," and, with regard to severe economic inadaptability, nothing in Diagnostic Code 8100 requires that the claimant be completely unable to work in order to qualify for a 50 percent rating. Pierce v. Principi, 18 Vet. App. 440, 445-46 (2004). The M21-1 provides that evidence of work impairment includes, but is not necessarily limited to, the use of sick leave or unpaid absence. See M21-1, V.iii.12.A.3.e. (June 21, 2021). In rating headaches or migraines under Diagnostic Code 8100, the Board may not consider the ameliorative effects of medication. See Jones v. Shinseki, 26 Vet. App. 56, 63 (2012). With regard to lay evidence, the Veteran as a lay person is competent to describe observable characteristics of his headaches. See Pierce v. Principi, 18 Vet. App. 440, 445 (2004) (lay evidence can be probative as to the frequency, prolongation, and severity of headaches). Frequency of headache attacks or episodes is a factual determination. The VA must analyze all medical, lay, and other evidence in the record bearing on that question. And the absence of medical treatment is not necessarily probative on the question of headache frequency as a claimant may not seek treatment for headaches during every episode. See e.g., Buchanan v. Nicholson, 451 F.3d 1331, 1336 (Fed. Cir. 2006) (the mere absence of medical records does not contradict a Veteran's statements about his symptom history). The M21-1 emphasizes that with regard to lay evidence of prostration, "a claimant's own testimony regarding symptoms and limitations when having those symptoms can establish prostration as long as the testimony is credible, and symptoms are otherwise competently attributed to migraine headaches through medical evidence." See M21-1, V.iii.12.A.3.d. (June 21, 2021). The absence of clinical treatment reports is not necessarily probative on the question of headache frequency as a claimant may not seek treatment for headaches during every episode. Id. at Block g. The Board highlights that the Court's holding that Diagnostic Code 8100 for migraine headaches contemplates "all symptoms" experienced due to migraine headache attacks, such as various non-headache symptoms dizziness, nausea, vertigo, mood swings, sleep impairment, photophobia, anxiety, isolation, and depression. In short, the rating criteria for migraines (Diagnostic Code 8100) contemplate all migraine symptoms. Holmes v. Wilkie, 33 Vet. App. 67, 73-75 (2020). VA must then rate these symptoms based on the frequency, duration, severity, and economic impact of the attacks under Diagnostic Code 8100. Id. at 72-73. However, the Court in Holmes emphasized that nothing in its analysis of Diagnostic Code 8100 forecloses the possibility that a veteran's migraine headaches could require additional compensation through mechanisms such as secondary service connection, a TDIU, or even an extraschedular rating under 38 C.F.R. § 3.321(b), if there was an exceptional case with symptoms more severe, frequent, or long-lasting than what is contemplated by the rating criteria. Id. at 73. See also 38 C.F.R. §§ 3.310(a), 3.321, 4.16. Upon review, from August 26, 2013 to the present, the evidence of record supports a higher initial 50 percent rating for service-connected tension headaches under Diagnostic Code 8100. The claim is thus granted. This is the maximum schedular rating available for headaches under the applicable diagnostic code. Specifically, when adjusting for the fact that for the entire time period in question, the Veteran took various medications (Tylenol, ibuprofen, opioids, Elavil, and trigger point injections) to control the severity of his tension headache attacks, the medical and lay evidence of record establishes migraine headaches with "very frequent completely prostrating and prolonged attacks productive of severe economic inadaptability," thereby meeting the criteria for a 50 percent rating. See 38 C.F.R. § 4.124a. Moreover, in making this favorable determination, under Diagnostic Code 8100, the Board has considered the functional impact of "all symptoms" experienced due to tension headache attacks, such as various non-headache symptoms the Veteran has occasionally reported sleep impairment, impact on mood, nausea, fatigue, dizziness, diminished concentration, blurred vision, and sensitivity to light and sound. See Holmes, 33 Vet. App. at 73-75 (2020). The Veteran's tension headache attacks are very frequent (at least four times per month or more), completely prostrating (he is incapacitated and has to lay down in bed in a dark environment when they occur), prolonged (the headaches can last 12 a day to four days), and productive of severe economic inadaptability (he cannot work three or more days per month when they occur at this level of severity). Therefore, even with medication use, the Veteran still meets some, if not all of the criteria listed for the 50 percent rating under Diagnostic Code 8100. But without the use of medication, he clearly would meet all of the criteria for a 50 percent rating. At times during the appeal period, when his medication was effective in controlling her headaches, it can be argued that his headache attacks were not completely prostrating and were not productive of severe economic inadaptability. However, a higher rating may not be denied on the basis of relief provided by medication when those effects are not specifically contemplated by the rating criteria. Jones v. Shinseki, 26 Vet. App. 56, 63 (2012). The rating criteria for headaches listed under Diagnostic Code 8100 fail to consider the ameliorative effects of medication on the Veteran's tension headaches. Therefore, the Board is obligated to contemplate the severity of his tension headaches absent the use of his various medications (Tylenol, ibuprofen, opioids, Elavil, and trigger point injections) he has taken to control his headaches since August 26, 2013, and even beforehand. In making this determination that the Veteran is entitled to the maximum 50 percent rating for his service-connected tension headaches under Diagnostic Code 8100 for the entire appeal period from August 26, 2013 to the present, the Board has considered the following favorable evidence of record: As early as an August 2004 VA preventive medicine risk assessment screening, which the Veteran filled out in June 2004, reported headaches with blurred vision. He takes Tylenol and Aleve to control his headaches. Private treatment records from the Pain Management and Rehabilitation Center, dated in 2010, 2011, and 2012, recorded "frequent" headaches for the Veteran. The clinicians noted complaints of sinus headaches / tension headaches, for which the Veteran takes Elavil. He also undergoes trigger point injections to control his headaches, which are worse in the spring and fall. In August 2011 the Veteran was off work for two weeks due to "severe" headaches. This corresponds to the criteria of "very frequent" and "prolonged" headaches, somewhat supportive of a maximum 50 percent rating under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. A July 2013 Rosecrance private mental health assessment commented that the Veteran was taking opioids to treat his headaches, which were "constant" in nature. His headaches also interfere with his activities of daily living. A September 2013 SSA treatment record mentioned the Veteran's assertion of "lots of headaches." With regard to VA treatment records, a December 2012 VA nursing outpatient note confirmed the Veteran awoke the night before with a bad headache. The headache was "constant" and tolerable, but there are intermittent "electrical shocks of intense pain like an ice cream" during which times the headaches were "intolerable" and 9/10 in severity. A December 2012 VA mental health telephone encounter note found that the Veteran was experiencing headaches. A January 2013 VA mental health outpatient note conveyed treatment for headaches. An August 2013 VA nursing outpatient note remarked that the Veteran's headaches were "constant" for the past week. A January 2014 VA SATP group counseling note revealed "persistent" headaches. A January 2014 VA mental health telehealth note by a VA psychiatrist advised that the Veteran was engaging in substance abuse with opioids in order to "self-medicate" his "severe" headaches. A December 2014 VA nursing triage note documented complaints of headaches 8 to 9 out of 10 in severity. VA treatment records in March 2017 assessed "severe" headaches on multiple occasions due to stress. VA treatment records dated in April 2017 and May 2017 recorded "severe" headaches. A March 2020 VA addendum note recorded headaches with pain of a severity of 8/10. He has taken Tylenol and other prescription medications to treat his headaches. VA treatment records dated in 2020 and 2021 contained complaints of headaches accompanied by nausea. This VA evidence corresponds to the criteria for a maximum 50 percent rating under Diagnostic Code 8100, in that his headaches were "very frequent" (more than one per month or "constant" and "persistent") and "completely prostrating" (at times intolerable and severe). See 38 C.F.R. § 4.124a. A September 2017 private psychological evaluation and opinion by Heather Henderson-Galligan, psychologist, opined that the combination of the Veteran's service-connected headaches, right shoulder, low back, and mental health disorders have rendered him "incapacitated." A June 2018 private residual functional capacity evaluation for headaches from Dr. H.S., MD., a family medicine physician, related the Veteran misses 4 days per month due to headaches (by 2012 the Veteran was no longer working according to the evidence of record). He would need to leave work early 3 days per month due to headaches. He has difficulty concentrating from his headaches on a daily basis. Dr. H.S. felt the Veteran was unable to maintain substantially gainful employment due to his headaches. A June 2018 private headaches DBQ (VA Form 21-0960C-8) from the same private physician, Dr. H.S., MD, assessed "frequently prostrating tension headaches." Within the past 10 years, the Veteran's headaches have "significantly intensified in frequency and severity." He has to lay down in a dark environment from half a day to a whole day with an 8/10 severity level of headache pain. This severe symptomatology occurs four times per month, lasting up to four days each time. His typical headaches lasts 12-24 hours, four times a month. He takes OTC pain medications. His headache pain is constant, pulsating, on both sides of his head, and on the top of head. He has non-headache symptoms too - sensitivity to light and sound, changes in vision, dizziness, blurred vision, and grossly diminished concentration. He displays "very frequent prostrating and prolonged attacks of non-migraine headache pain." These headaches preclude him from being able to maintain focus on even minor work tasks. Dr. H.S. concluded that the Veteran exhibits "frequently prostrating episodes" of headaches occurring up to four days, lasting approximately four times each month for the past 10 years, which has resulted in "severe" economic inadaptability, due to missing three or more days of work each month from diminished focus from his headaches. This corresponds to the criteria of "very frequent" and "prolonged" and "completely prostrating" headaches, supportive of a maximum 50 percent rating under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. His headaches are at times "prolonged" in that they can last for hours or even days according to the Veteran. Johnson, 30 Vet. App. at 248. These headaches are also "productive of severe economic inadaptability" according to Dr. H.S. See 38 C.F.R. § 4.124a. With regard to lay evidence, in a July 2022 statement and in a November 2018 Attorney Brief, the Veteran competently and credibly stated that his headaches result in him missing three or more days per month from work due to "severe" pain and diminished focus. The Veteran competently and credibly described his headache pain as "severe, debilitating head pain" when at its worst, resulting in a severe economic adaptability. His headaches occur every other day but vary in severity. He takes Tylenol to control his headaches. When his headaches are severe three or more days per month, he related that he lies in a dark room, feeling fatigue, stomach distress, dizziness, blurred vision, visual acuity decrease, irritability, isolation, and anxiety. The Board emphasizes that lay evidence may be probative as to the frequency, prolongation, and severity of headaches. Pierce, 18 Vet. App. at 445-46. The Veteran's lay description of his headaches is mostly credible, corresponding to the criteria of "very frequent" and "prolonged" and "completely prostrating" headaches, supportive of a maximum 50 percent rating under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. In summary, the Board concludes that if the Veteran did not constantly take prescription and non-prescription medications, his tension headaches would nearly always be classified as very frequently "completely prostrating" and contributing to prolonged attacks productive of "severe" economic inadaptability. This corresponds to the criteria for a maximum 50 percent rating under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. His headaches occur on a "very frequent" basis, connoting a frequency at least greater than once a month. Johnson, 30 Vet. App. at 253. Absent his medication use, the headaches would more often be "completely prostrating," meaning they would render the Veteran entirely powerless. Id. His headaches can be "prolonged" in that they can last for hours or even days, according to the Veteran. Johnson, 30 Vet. App. at 248. And absent his various medications, his headaches would be almost always "productive" of severe economic inadaptability, meaning "producing" or "capable of producing," severe economic inadaptability. Pierce, 18 Vet. App. at 445-46. In this regard, although the Veteran last worked in 2012, private and SSA medical records confirm that during flare-ups, his tension headaches would make him miss work, sometimes for over a week. They impacted his ability to concentrate in the factory setting where he used to work. However, nothing in Diagnostic Code 8100 requires the Veteran to be completely unable to work due to his headaches, in order to qualify for the maximum 50 percent rating. Id. Finally, in awarding the maximum 50 percent rating, the Board has considered the effect of other symptoms occasionally associated with his headaches sleep impairment, fatigue, impact on mood, nausea, fatigue, dizziness, diminished concentration, blurred vision, and sensitivity to light and sound. Holmes, 33 Vet. App. at 73-75. In making this favorable determination, the Board acknowledges that VA headache examiners in November 2015, April 2018, and January 2022 all opined that the Veteran did not meet the criteria for a higher 50 percent rating. That is, these VA examiners assessed that at their worst, the Veteran's tension headaches manifested in characteristic prostrating attacks of migraine / non-migraine headache pain once every month, at which time he had lay in bed the entire day. The VA examiners also opined that the Veteran did not experience any extra non-headache symptoms, associated with his service-connected headaches. As such, the VA examiners' findings are only supportive of a 30 percent rating, at best, for his tension headaches under Diagnostic Code 8100. See 38 C.F.R. § 4.124a. However, the conclusions of the VA examiners are unsupported and outweighed by the other VA and private treatment records and medical opinions of record and the Veteran's lay statements, all of which throughout the entire appeal period reveal a more complete disability picture for the Veteran's tension headaches. It is not error for the Board to favor the opinion of one competent medical expert over that of another when the Board gives an adequate statement of reasons or bases. See Owens v. Brown, 7 Vet. App. 429, 433 (1995). What's more, the Board, as fact finder, is responsible for assessing the competence, credibility, and probative value of evidence. See Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006). The Board emphasizes that the AOJ or the Board (the rating activity), not the examining medical professional, interprets the medical reports in order to match the rating with the disability. Moore v. Nicholson, 21 Vet. App. 211, 218 (2007). Accordingly, from August 26, 2013 to the present, a maximum 50 percent rating is warranted for the Veteran's service-connected tension headaches. 38 C.F.R. § 4.3. No higher schedular rating is available for this disability. The claim is granted. Finally, for the increased rating issue for tension headaches, neither the Veteran nor his attorney has raised any other issues, nor have any other issues been reasonably raised by the record. See Yancy v. McDonald, 27 Vet. App. 484, 495 (2016); Doucette v. Shulkin, 38 Vet. App. 366, 369-70 (2017) (confirming that the Board is not required to address issues unless they are specifically raised by the claimant or reasonably raised by the evidence of record). Moreover, the Veteran has not explained how the totality of his migraine symptoms would exceed the 50 percent schedular rating criteria contained in Diagnostic Code 8100. See Holmes, 33 Vet. App. at 75. REASONS FOR REMAND 1. Service connection for a LEFT shoulder disorder is REMANDED. For the LEFT shoulder, the Veteran should be scheduled for the appropriate VA examination to determine the existence and etiology of any current LEFT shoulder disorder. See McLendon v. Nicholson, 20 Vet. App. 79, 81 (2006); see also 38 U.S.C. § 5103A(d)(2); 38 C.F.R. § 3.159(c)(4). In this regard, an earlier November 2018 VA shoulder examination and a latter January 2022 VA shoulder examination and medical opinion addressed whether a current LEFT shoulder disorder existed, and the etiology of same. The January 2022 VA shoulder examiner determined that there was no nexus between the Veteran's current LEFT shoulder strain and his period of active service in the Marine Corps from 1988 to 1992, to include a 1989 football injury to his opposite right shoulder and to include presumed toxic exposure to environmental hazards in the Persian Gulf. It was noted that the Veteran's STRs dated from 1988 to 1992 were negative for any treatment or diagnosis of a LEFT shoulder disorder. Nevertheless, although probative, the January 2022 VA shoulder examination and opinion was not fully adequate. On this point, when VA provides a VA examination or obtains a VA opinion, it must ensure that the examination or opinion is adequate. Barr v. Nicholson, 21 Vet. App. 303, 312 (2007). The January 2022 VA shoulder examination and opinion was not fully adequate because another theory of etiology for service connection was raised by the record but not addressed by the January 2022 VA shoulder examiner. That is, in a July 2022 Veteran statement (subsequent to the January 2022 VA examination), the Veteran asserted that his LEFT shoulder pain developed over time post-service as the result of "wear and tear" from physical training exercises during his four years of active duty in the Marine Corps. In Schroeder v. West, 212 F.3d 1265, 1271 (Fed. Cir. 2000), the Federal Circuit held that VA's duty to assist attaches to the investigation of all possible in-service causes of a disability, including those unknown to the veteran. Under VA regulation, disorders diagnosed after discharge may still be service connected if all the evidence, including pertinent service records, establishes the disorder was incurred in service. See 38 C.F.R. § 3.303(d). In this regard, a new VA shoulder examination and medical opinion for the LEFT shoulder is necessary to address whether any current LEFT shoulder, to include the Veteran's documented shoulder strain and any possible shoulder arthritis (if shown by X-ray), developed over time post-service due to his rigorous physical training in the Marine Corps that involved frequent running, jumping, marching, crawling, hiking, heavy lifting, and carrying. 2. Service connection for gastroesophageal reflux disease (GERD) (an esophageal condition) on a secondary basis to service-connected PTSD, major depressive disorder, alcohol and polysubstance abuse disorders, and tension headaches is REMANDED. 3. Service connection for gastritis (a stomach or duodenal condition) on a secondary basis to service-connected PTSD, major depressive disorder, alcohol and polysubstance abuse disorders, and tension headaches is REMANDED. For the GERD and gastritis disorders, the AOJ must obtain a VA addendum opinion from the same VA clinician who performed the earlier January 2022 VA esophagus, stomach, and duodenum examinations and opinions. (This VA clinician also provided a February 2022 VA addendum opinion for the stomach). The January 2022 VA examiner adequately addressed the issue of direct in-service incurrence for the Veteran's GERD and gastritis disabilities. However, although probative, the January 2022 and February 2022 VA medical opinions were not fully adequate in that the VA examiner failed to address all reasonably raised theories of etiology such as secondary service connection for the Veteran's GERD and gastritis disabilities. See e.g., July 2000 medical treatise article received on March 20, 2019, titled "Comorbidity of Depressive and Anxiety Disorders in Chronic Daily Headache and Its Subtypes"; August 19, 2011 VA mental health initial evaluation note (the Veteran was recently put on FMLA because of feeling anxiety and stress to the point where his stomach hurt); August 25, 2011 VA mental health outpatient note (Amitriptyline taken for his service-connected insomnia made his stomach feel numb). Once again, the Federal Circuit has held that VA's duty to assist attaches to the investigation of all possible in-service causes of a disability, including those unknown to the Veteran. Schroeder, 212 F.3d at 1271. When determining service connection, all theories of entitlement, direct and secondary, must be considered if raised by the evidence of record, applying all relevant laws and regulations. Szemraj v. Principi, 357 F.3d 1370, 1371 (Fed. Cir. 2004). Therefore, although it will result in additional delay in adjudicating the appeal, a remand is required to obtain a VA addendum opinion on whether the Veteran's current GERD and gastritis disabilities are proximately due to or aggravated beyond their natural progression by his service-connected PTSD, major depressive disorder, alcohol, and polysubstance abuse disorders, and / or tension headaches. See 38 C.F.R. §§ 3.159(c)(4)(i)(C), 3.310. See also McLendon v. Nicholson, 20 Vet. App. 79, 81 (2006). In this respect, if a medical opinion does not address the secondary aspect of a claim, it is not sufficient for rating purposes. Robinson v. Mansfield, 21 Vet. App. 545 (2008). If the same January 2022 VA esophageal, stomach, and duodenum examiner is not available, another qualified VA clinician will provide the addendum opinion. Additional VA esophagus, stomach, and duodenum examinations for the Veteran's GERD and gastritis disabilities are not necessary here. 3. Entitlement to a total disability rating based on individual unemployability (TDIU) due to service-connected disabilities is REMANDED. As discussed in detail above, in accordance with the holding of Rice v. Shinseki, 22 Vet. App. 447, 453-54 (2009), the issue of entitlement to a TDIU has been added to the present appeal. However, the TDIU issue is inextricably intertwined with the implementation of the awards of service connection, secondary service connection, and an increased rating for the various disabilities granted in the present Board decision. That is, since the Board in the present decision has granted service connection for multiple disabilities, secondary service connection for multiple disabilities, and an increased rating for tension headaches and a lumbosacral strain, the AOJ's assignment of a disability rating and effective date for these awards will impact the adjudication of the TDIU claim. See 38 C.F.R. § 4.16(a). For this reason, the implementation of these service connection and increased rating awards by the AOJ must be resolved prior to resolution of the claim for TDIU. See Harris v. Derwinski, 1 Vet. App. 180, 183 (1991) (noting that the prohibition against the adjudication of claims that are inextricably intertwined is based upon the recognition that claims related to each other should not be subject to piecemeal decision-making or appellate litigation). Accordingly, a remand is required for the AOJ to adjudicate the inextricably intertwined claims. In addition, for the TDIU issue, after completing this development, the AOJ must adjudicate the TDIU issue on appeal in the first instance. Therefore, the above issues are REMANDED for the following action: 1. Schedule the Veteran for a VA shoulder examination by an appropriate clinician to determine the etiology of any current LEFT shoulder disability. The VA examiner must review the claims file. The Veteran must be interviewed. Any and all studies, tests, and evaluations deemed necessary by the VA examiner should be performed, including X-rays of the LEFT shoulder. The VA examiner must address the Veteran's relevant lay assertions, and if necessary, address whether the Veteran's lay assertions are consistent or inconsistent with his medical history and the clinical data. Finally, the VA examiner must provide a clear rationale for the medical opinions. The VA examiner must respond to the following inquiries: (a.) Please perform X-rays for the LEFT shoulder to determine if the Veteran has any LEFT shoulder arthritis, in addition to his already diagnosed LEFT shoulder strain. (It appears from the record that no clinician has performed X-rays for the Veteran's LEFT shoulder to determine if he has arthritis). (b.) Is it at least as likely as not (i.e., (likelihood is at least approximately balanced or nearly equal, if not higher)) that the Veteran's diagnosed LEFT shoulder strain or any arthritis (if seen on X-ray) is causally or etiologically to the Veteran's four-year period of service in the Marine Corps from 1988 to 1992? Specifically, did the Veteran's current LEFT shoulder disorder(s), to include a documented shoulder strain and any possible shoulder arthritis (if shown by X-ray), develop over time post-service due to his rigorous physical training activities that involved frequent running, jumping, marching, crawling, hiking, heavy lifting, and carrying in the Marine Corps from 1988 to 1992? In answering this particular question, the VA examiner is advised the Veteran is credible in describing his rigorous physical training activities as discussed above. The VA examiner should explain whether the Veteran's participation for four years in these credible in-service physical training activities caused his LEFT shoulder strain and any possible LEFT shoulder arthritis (if shown by X-ray), to develop over time post-service, even though he received no documented treatment for the LEFT shoulder during active duty or for many years thereafter, according to the Veteran's STRs (1988 to 1992) and his post-service medical records. (c.) In rendering the above opinions, the VA examiner should focus on the following relevant evidence: STRs dated from 1988 to 1992 are negative for any complaint, treatment, or diagnosis of a LEFT shoulder disorder. At his July 1992 STR separation examination, the Veteran denied a history of LEFT shoulder problems, and no LEFT shoulder disorder was objectively seen upon examination. Post-service, in a November 2012 VA mental health outpatient note and at a July 2013 Rosecrance private mental health assessment, the Veteran reported pain in both of his shoulders. However, subsequently, no LEFT shoulder discomfort was reported or objectively seen at November 2015 and April 2018 VA shoulder examinations. At a latter January 2022 VA shoulder examination, the Veteran was finally diagnosed with a LEFT shoulder strain. But no X-rays were performed for the LEFT shoulder to determine if degenerative or traumatic arthritis existed at that time. 2. For the GERD and gastritis disorders, secure a VA addendum opinion from the VA clinician who performed the January 2022 VA esophageal, stomach, and duodenum examinations and opinions. If this VA clinician is no longer available, another qualified VA clinician must provide the addendum opinion. Only if deemed necessary by the VA examiner are additional VA esophageal, stomach, and duodenum examinations necessary. The VA examiner must review the claims file. The VA examiner must provide a rationale to support the opinion. The VA examiner is asked to provide a response to the following inquiries: (a.) Are the Veteran's current GERD and gastritis disorders "at least as likely as not" (i.e., (likelihood is at least approximately balanced or nearly equal, if not higher)) proximately due to his now service-connected PTSD, major depressive disorder, and alcohol and polysubstance abuse disorders, OR to his service-connected tension headaches disability? (b.) Are the Veteran's current GERD and gastritis disorders "at least as likely as not" (i.e., (likelihood is at least approximately balanced or nearly equal, if not higher)) aggravated by, i.e., worsened beyond their natural progression by his now service-connected PTSD, major depressive disorder, and alcohol and polysubstance abuse disorders, OR by his service-connected tension headaches disability? The VA examiner is cautioned to not combine the causation and aggravation facets of secondary service connection, as [under governing caselaw] they are independent concepts requiring separate findings and rationale. That is, a VA medical opinion cannot provide the same rationale to both the causation and aggravation elements and must distinguish between the two theories, as they are separate. For example, a disability can theoretically aggravate another disorder, even if it did not cause it. (c.) In rendering the above opinions on secondary service connection, the VA examiner shoulder focus on the following relevant evidence of record: a July 2000 medical treatise article received on March 20, 2019, titled "Comorbidity of Depressive and Anxiety Disorders in Chronic Daily Headache and Its Subtypes" (nausea and vomiting are common to certain mental health disorders and to migraine headaches); August 19, 2011 VA mental health initial evaluation note (the Veteran was recently put on FMLA because of feeling anxiety and stress to the point where his stomach hurt); and August 25, 2011 VA mental health outpatient note (Amitriptyline taken for the Veteran's service-connected insomnia made his stomach feel numb). 3. After completion of steps 1-2, implement the following grants of service connection awarded in the present Board decision: service connection for PTSD; service connection for major depressive disorder with associated anxiety, insomnia, and memory loss; service connection for a bowel disturbance with abdominal distress (an intestinal condition); service connection for type II diabetes mellitus; service connection for hyperlipidemia (high cholesterol) with angina (chest pain); secondary service connection for hypertension, diabetic neuropathy of the RIGHT and LEFT lower extremities, and an alcohol abuse disorder and polysubstance abuse disorder. Assign a disability rating (or ratings) and effective date for these awards. Also implement the following grants of increased ratings awarded in the present Board decision: a 20 percent rating for a lumbosacral strain and a 50 percent rating for tension headaches (awarded throughout the entire appeal period). Assign the effective date for these increased rating awards. 4. After completion of steps 1-3, the AOJ must adjudicate in the first instance the intertwined issue of entitlement to a TDIU, as well as readjudicate the service connection issue for a LEFT shoulder disorder and the secondary service connection issues for GERD and gastritis. DAVID L. WIGHT Veterans Law Judge Board of Veterans' Appeals Attorney for the Board P.S. Rubin, Counsel The Board's decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.