In a nested case-comparison study, Black et al. (2004a) conducted face-to-face interviews with 602 veterans in 1999-2002. They used the Structured Clinical Interview for DSM-IV (SCID) with a random group of veterans drawn from strata of the PRIME-MD-interviewed group who reported one or more of the following symptom-based conditions during their previous interview: depression (major or minor depression), widespread chronic pain (established criteria for generalized, severe, and chronic pain), and cognitive dysfunction (amnesia or cognitive impairment of a moderate and prolonged intensity). Veterans were stratified by each symptom combination (one, two, or all) and by deployed or non-deployed status. Controls did not have any of those conditions and might have been deployed or not deployed. The veterans were selected randomly for interview from each stratum to optimize the match between cases and controls; interviewers were trained in the use of the diagnostic instruments.
Personality disorders were assessed with the SNAP (Schedule for Nonadaptive and Adaptive Personality). Level of functioning was assessed using the SF-36 (36-Item Short-Form Health Survey). The Whiteley Index was used to determine hypochondriasis. The study found a 32% rate of lifetime depression diagnosis (all types) and that was the same in deployed and nondeployed veterans. There were few diagnostic differences between the depressed deployed and the depressed nondeployed veterans, except for PTSD (27.3% in deployed, 5.0% in non-deployed), anxiety disorders (51.5% deployed and 25.0% non-deployed) and any disorder (68.2% deployed and 51.7% non-deployed). The deployed depressed veterans were more likely to have a diagnosis of any substance-use disorder (69.7% in deployed vs 51.7% in non-deployed). What was most surprising about the direct interview analysis was that there was so little difference between the deployed and the nondeployed veterans in aspects of depression (36.6% vs 30.3%). Most differences were found in anxiety disorder (51.5% vs 25.0%) as noted above.
Kang et al. (2003) conducted a population-based stratified random sample of 15,000 US Gulf War troops compared to a similar sample of troops deployed elsewhere. Phase 1 was a mail survey and phase 2 was a telephone-based survey of PTSD symptoms and chronic fatigue (CFS) symptoms. In the interview cohort, 12.1% of Gulf War veterans and 4.3% of other veterans had symptoms of PTSD, with an adjusted OR of 3.1 (95% CI 2.7-3.4) for PTSD in the Gulf War group; and 6% of the Gulf War veterans and 1.2% of the other veterans (OR 4.8) had CFS symptoms. It was interesting to note that PTSD symptoms showed a monotonic relationship to intensity of war stress, whereas the CFS symptoms did not show any relationship to war stress. The rates of PTSD tracked rates of stressors closely. Deployment, but not war stress, was associated with CFS symptoms.
Wolfe et al. (1999a; 1999b), and Proctor et al. (1998) examined cohorts of veterans randomly sampled and stratified from the Fort Devens and New Orleans-deployed Gulf War veterans, as well as a cohort deployed to Germany (a noncombat area). The Gulf War-deployed veterans from Fort Devens were followed longitudinally from the day of their arrival home from the gulf (time 1) to about 2 years later (time 2) with a 78% participation rate. The Fort Devens cohort was mainly male, Caucasian, and National Guard; rates of PTSD measured at time 1 were 3%. From those cohorts, stratified random samples were selected for closer study with direct interview (220 of the Fort Devens cohort, 73 of the New Orleans cohort, and 48 of the Germany-deployed). The researchers used questionnaires (the 52-item expanded Health Symptoms Checklist [HSC] and the Expanded Combat Exposure Scale), a neuropsychologic test battery, an environmental interview, and psychiatric diagnostic instruments (the Clinician-Administered