Secondary studies were based primarily on retrospective or cross-sectional study designs with self-reported information whose major limitations were poor response rates and the potential for recall bias. The number and types of psychiatric disorders reported varied widely from study to study and included current (those occurring in the preceding month or week), 12-month, and lifetime reports mainly of MDD, GAD, alcohol abuse or dependence, specific phobias, and PTSD. Although many of the studies used different case definitions or different screening instruments, one (Eisen et al. 2004) assessed the test-retest reliability of the DIS-III-R interviews used. The investigators found that in general test-retest reliability of the lifetime prevalence of most of the DSM-III-R psychiatric diagnoses was acceptable (Kappa statistics 0.54-0.76); however, reliability was poor (Kappa statistic < 0.40) for panic disorder and GAD.
Eleven secondary studies on nine veteran populations used self-reported data to consider whether deployed veterans differed from nondeployed veterans for a wide variety of psychiatric disorders (Black et al. 2004a; Dlugosz et al. 1999; Erickson et al. 2001; Forman-Hoffman et al. 2005; Goss Gilroy Inc. 1998; Gray et al. 2002; Grieger et al. 2006; Hoge et al. 2004, 2006; O’Toole et al. 1996a; Simmons et al. 2004). O’Toole et al. (1996a) studied Australian Vietnam veterans, and Hoge et al. (2004, 2006) studied U.S. troops returning from OEF and OIF; the other eight studies studied Gulf War veterans.
In 1997, Goss Gilroy Inc. (1998) mailed a health-status questionnaire to all Canadian military personnel who had deployed to the Gulf War (n = 4262) and a comparison group of Canadian military personnel who had served elsewhere (n = 5699), matched on age and gender. The response rates were 73% (n = 3113) and 60.3% (n = 3439), respectively. The major self-reported health outcomes found to be significantly increased in deployed Gulf War veterans, compared with nondeployed veterans, were health provider-diagnosed PTSD (OR 3.34, 95% CI 2.13-5.26), anxiety (OR 2.20, 95% CI 1.55-3.12), MDD (OR 3.67, 95% CI 3.04-4.44), and symptoms of PTSD (OR 2.69, 95% CI 1.69-4.26).
Gray et al. (2002) conducted a cross-sectional survey in 1997-1999 of 3831 active-duty and reserve Navy Seabees who had served in the Gulf War and 3104 Seabees who had remained in the United States. The mailed survey gathered self-reports on prewar medical history, war exposure, symptoms, geographic service during the war, PTSD, depression, and anxiety. For deployed vs nondeployed Seabees, risks were significantly increased for depression (OR 1.77, 95% CI 1.41-2.27), PTSD (OR 4.23, 95% CI 2.59-6.92), and suicidal thoughts (OR 2.16, 95% CI 1.64-2.84) when adjusted for age, sex, active-duty or reserve status, race or ethnicity, current smoking, and current alcohol drinking.
Using the Iowa Persian Gulf cohort, Black et al. (2004b) administered a telephone survey to a population-based sample of 4886 members of the military in Iowa who were enlisted at the time of the Gulf War. Subjects were randomly selected from Gulf War regular military and National Guard or reserves and non-Gulf War regular military and National Guard or reserves. Medical and psychiatric disorders were assessed in 3695 of those selected, with a final participation rate of 76%. Deployed military personnel (n = 1896) were twice as likely as nondeployed military personnel (n = 1799) to report having a current anxiety disorder (estimated prevalence 4.0% [SE 1.0] vs 1.8% [SE 0.4]) or any anxiety disorder (estimated prevalence 5.9% [SE 0.6] vs 2.8% [SE 0.5]). In a multivariate model, predeployment psychiatric difficulties—which included predeployment psychiatric treatment and predeployment diagnosis of PTSD, depression, or anxiety—were independently associated with current anxiety disorder; this suggested that predeployment precursors were associated with development of anxiety (OR 4.4,