the Fort Devens group had twice the prevalence of lifetime MDD as the New Orleans group (22.5% Fort Devens, 10.2% New Orleans, and 4.2% Germany-deployed). The investigators found a small but significant association between increased health-symptom reports and the diagnosis of PTSD or MDD for the combined deployed groups. However, almost two-thirds of gulf participants reporting moderate to high health symptoms were found to have no axis I (major psychiatric) disorders. The rates of most psychiatric disorders were lower than national comorbidity estimates except PTSD, MDD, and dysthymia, which had rates similar to those in the National Comorbidity Survey (NCS) (Kessler et al. 1995). The Wolfe et al. study had a participation rate of 62% for the Fort Devens cohort and 85% for the Germany-deployed unit, but budget constraints limited participation by the New Orleans cohort to 37%.
Fiedler et al. (2006) compared the prevalence of MDD, panic attacks, social phobia, obsessive-compulsive disorder, GAD, and any psychiatric disorder in random samples of 967 Gulf War-deployed veterans and 784 era veterans. The sample was obtained from the DMDC. Study participants were administered the 12-month version of the CIDI using the DSM-IV criteria to assess PTSD and the CIDI-Short Form/DSM-IV for the remaining psychiatric disorders by telephone interview with computer-assisted technology. Deployed veterans had a significantly greater prevalence of any psychiatric disorder than nondeployed veterans (26.1% vs 16.1%, p < 0.05) including MDD (15.1% vs 7.8%), panic attack (1.6% vs 0.5%), social phobia (3.6% vs 1.7%), obsessive-compulsive disorder (2.8% vs 1.1%), PTSD (3.4% vs 0.9%), GAD (6.0% vs 2.7%) and any anxiety disorder (16.0% vs 9.7%). After control for demographic variables and other psychiatric disorders, deployed veterans were found to have higher risks of MDD (OR 2.07, 95% CI 1.50-2.85) and any anxiety disorder (OR 1.81, 95% CI 1.34-2.45). Lower rank, female sex, and divorced-single status all were significant independent predictors of psychiatric disorder. The study is limited in that the response rate was suboptimal (55%) and responders differed from nonresponders in that a greater proportion of whites and officers volunteered for the study.
In a recent study by Toomey et al. (2007), 1061 veterans deployed to the Gulf War were compared with 1128 Gulf War-era veterans. They used the randomly selected subset of 11,441 deployed and 9476 nondeployed veterans who have been followed since 1995 for the National Health Survey of Gulf War Era Veterans and Their Families (Eisen et al. 2005). The study used structured clinical interviews for all psychologic examinations conducted in 1998-2001; PTSD was diagnosed with the CAPS, and the CIDI was used to diagnose the other axis I psychiatric disorders. The investigators calculated the prevalence of mental disorders beginning during the deployment period and evaluated their prevalence 10 years later. They found that 10 years after the end of the Gulf War, those deployed to that region had a persistent increased prevalence of mental disorders, especially PTSD (OR 5.78, 95% CI 2.62-12.74), all anxiety disorders (OR 4.43, 95% CI 2.49-7.88), and MDD (OR 1.81, 95% CI 1.03-3.32). The multiple-regression model was adjusted for age, sex, ethnicity (white vs other), years of education (less than 12 vs 12 or more), duty type (active vs reserve or Guard), service branch (Army or Marines vs Navy or Air Force) and rank (enlisted vs officer) unless otherwise noted. The participation rates in the study were 53% for the deployed veterans and 39% for the nondeployed; the authors examined possible participation bias and determined that, overall, participation bias was independent of deployment status.