The committee considered 11 citations on seven primary studies: three on veterans of the Vietnam War and four on veterans of the Gulf War. Three of the publications on Vietnam veterans were based on the NVVRS, one on the VES, and two on the Vietnam Era Twin Registry. Of the publications on Gulf War veterans, two studies analyzed datasets from well-defined cohorts from Louisiana, Massachusetts, and Maine; one used a subset of veterans from the National Health Survey of Gulf War Era Veterans and Their Families; one used a random sample of veterans; and one study looked at Australian Gulf War veterans. All the studies, regardless of the veteran population or the techniques of ascertainment, found that veterans who were deployed to war zones had a greater prevalence of psychiatric disorders—particularly PTSD, other anxiety disorders, and MDD—than did veterans who served in the military at the same time but were not deployed to a war zone. PTSD was also found to be highly comorbid with other psychiatric disorders, particularly GAD and MDD. Furthermore, both the prevalence and the severity of those disorders were associated with the level of combat experienced. The 11 secondary studies, most of them of Gulf War veterans, also showed an association between deployment and PTSD, other anxiety disorders, and MDD, as well as other psychiatric disorders.
The committee concludes that there is sufficient evidence of an association between deployment to a war zone and the development of psychiatric disorders, including PTSD, other anxiety disorders, and depressive disorders.