decreased feelings of control and efficacy have all been reported as possible explanations for the increases in PTSD symptoms observed with aging. However, little empirical research addresses these issues directly. Issues related to the variation in the battlefield environment (such as the nature of threats and trauma types experienced) across different war cohorts (World War II, Korea, Vietnam, and Operation Enduring Freedom/Operation Iraqi Freedom) compound the difficulty of assessing any changes in rates of PTSD in the aging veteran.

Based on its review, the committee concludes that the scientific literature supports the existence of a form of PTSD that manifests long after the occurrence of the stressor upon which the diagnosis is based. In addition, clinical experience indicates that some persons who are exposed to traumatic events may develop PTSD that is not recognized for an extended period of time and that others may develop some symptoms of PTSD that do not cross the diagnostic threshold to become incident cases of full PTSD until long after exposure to the stressor. The scientific literature does not identify any differences material to the consideration of compensation between these delayed-onset or delayed-identification cases and those chronic PTSD cases where there is a shorter time interval between the stressor and the onset of symptoms. The committee did not address the issue of whether there may be differences relevant to treatment decisions.

On the basis of the review of the papers, reports, and other information presented in this chapter, the committee has reached the following findings, conclusions, and recommendations, and identified the following research needs.

• The GAF score has limited usefulness in the assessment of the level of disability for PTSD compensation. The score is only marginally applicable to PTSD because of its emphasis on the symptoms of mood disorder and schizophrenia and its limited range of symptom content.

• There is no scientific guidance addressing the separation of symptoms of comorbid mental disorders for the purpose of identifying their relative contributions to a subject’s condition.

• The scientific literature supports the existence of a form of PTSD that manifests long after the occurrence of the stressor upon which the