concurring, by way of synopsis:
I compliment the author of this opinion for his time-consuming, detailed treatment of the issues raised or apparent in this appeal. However, the opinion’s prolixity and, I fear as to other readers, its convolution may cause the holdings of the Court to be obscured or misunderstood. Thus, I take the liberty briefly to outline what I see as the holdings and remedies we fashion. In this decision, we separate the medical “apple”— the now-subjective sufficiency of stressors, as described by a veteran, for a medical diagnosis of PTSD — from the adjudicatory “orange” — the determination by the VA fact finders that the stressors actually took place, substantially as recounted by the veteran.
Holdings
First, this claim of service connection for post-traumatic stress disorder (PTSD) is well *153grounded: Mr. Cohen currently has this disability; the lay evidence of a stressor or stressors in service is presumed credible for the purpose of determining whether his claim is well grounded; and medical professionals have connected his current disability to his service, again presuming the credibility of the stressors he and his lay witnesses have recounted. See Caluza v. Brown, 7 Vet.App. 498, 506 (1995), aff'd per curiam, 78 F.3d 604 (Fed.Cir.1996) (table).
Second, during the pendency of this appeal, VA has adopted, through rulemaking or policy, more current diagnostic criteria for PTSD, moving from those in the Diagnostic and Statistical Manual of Mental Disorders, third edition, to the revised third edition [DSM-III-R], to the fourth edition [DSM-IV]. The revision to the diagnostic criteria of the DSM-IV, made by a new regulation, has not changed 38 C.F.R. § 3.304(f), the PTSD regulation, but the new regulation amends 38 C.F.R. § 4.125 and § 4.126. The Secretary has also replaced 38 C.F.R. § 4.130 with a new section that specifically notes that the nomenclature employed in the rating schedule is based on DSM-IV. However, VA adjudicators also are guided by the VA Adjudication Procedure Manual, M21-1 [hereinafter Manual M21-1], The Manual M21-1 continues to apply the criteria set forth in the DSM-III-R. If these provisions are deemed not consistent in any respect, Mr. Cohen must receive the benefit of the most favorable version. See Karnas v. Derwinski, 1 Vet.App. 308, 312-12 (1991).
Third, the Court takes judicial notice of the effect of this shift in diagnostic criteria. The major effect is this: the criteria have changed from an objective (“would evoke ... in almost anyone”) standard in assessing whether a stressor is sufficient to trigger PTSD, to a subjective standard. The criteria now require exposure to a traumatic event and a response involving intense fear, helplessness, or horror. A more susceptible individual may have PTSD based on exposure to a stressor that would not necessarily have the same effect on “almost anyone.” The sufficiency of a stressor is, accordingly, now a clinical determination for the examining mental health professional.
Fourth, where, as in Mr. Cohen’s case, there has been an “unequivocal” diagnosis of PTSD by mental health professionals, the adjudicators must presume that the diagnosis was made in accordance with the applicable DSM criteria as to both adequacy of symptomatology and sufficiency of the stressor (or stressors). In examining these diagnoses, the adjudicators may reject a claim only upon finding a preponderance of the evidence against a PTSD diagnosis, against the occurrence of in-service stressor(s), or against the connection of the present condition to the in-service stressor(s).
Fifth, the Board must return a diagnostic report to the regional office (RO) for a further report by the examining doctor or other mental health professional when the Board believes the report does not accord with applicable DSM criteria. Here, the Board did not return the diagnostic reports on Mr. Cohen for clarification, despite expressed doubts regarding the adequacy of the PTSD diagnoses, specifically, the sufficiency of the stressor noted in the reports. Moreover, the Board did not discuss each of the three diagnostic reports in the record and failed to provide an adequate statement of reasons or bases for rejecting the examining medical professionals’ conclusions that Mr. Cohen has PTSD.
Accordingly, the Court reverses the BVA as to its rejection of the diagnosis of PTSD. This holding necessarily requires the conclusion that the stressors, as recounted by Mr. Cohen, were medically sufficient. The Board erred in finding the stressors insufficient and rejecting the diagnoses.
Remedy
Since the Court is precluded from finding fact, we must return this case to the BVA for the determination on the third essential regulatory element for service-connection of PTSD (that is, the link of the veteran’s current PTSD symptomatology to a specific stressor found to have occurred) and perhaps as to the second essential regulatory element (that is, the occurrence of the stressor(s) reported by Mr. Cohen). He has identified a number of stressors. One of these stressors, the mortar attacks, has been corroborated by a lay witness, whom the BVA has found *154credible. The occurrence of this stressor has thus been established on this record. If a link is found between this stressor and the veteran’s current PTSD, no further inquiry need be made. If not, and if the Board finds that Mr. Cohen was “engaged in combat” upon his return to the Da Nang air base from leave (or with respect to other stressors asserted, but not established), the relaxed evidentiary standards set forth in 38 U.S.C. § 1154(b) apply. Otherwise, verification of any such stressor is needed, and the Board must carry out its duty to assist Mr. Cohen in obtaining corroborating evidence from the Environmental Support Group, based, for example, on Mr. Cohen’s more specific information about his being fired upon at the Da Nang air base. If the Board requires more evidence concerning nexus to a specific in-service stressor of Mr. Cohen’s current symptoms, it must return the PTSD diagnosing reports to the examining mental health professional for clarification and, if ’needed, obtain further medical evidence on this issue.