In U.S. combat troops deployed to Afghanistan and Iraq, the risk of having PTSD 3-4 months after their return was 6.2% for Army troops returning from Afghanistan (odds ratio [OR] 1.26, 95% confidence interval [CI] 0.97-1.64) and 12.9% for Army (OR 2.84, 95% CI 2.17-3.72) and 12.2% for Marines (OR 2.66, 95% CI 2.01-3.51) returning from Iraq. The risk of having PTSD before deployment was 5.0% for all the military personnel screened using the PTSD Checklist (Hoge et al. 2004). A year after their return from Iraq, 16.6% of the U.S. Army combat troops met the screening criteria for PTSD (Hoge et al. 2007). The Department of Defense conducted a mental-health survey of Army soldiers and Marines deployed in Iraq in 2003, 2004, and 2006. In 2003, 16% of the soldiers and Marines met the screening criteria for PTSD while deployed; in 2004, 14% met the criteria; and in 2006, 17% of soldiers and 14% of Marines met the criteria (MHAT 2006).
The effects of the 1991 Gulf War on Army active-duty, and reserve or National Guard units from Pennsylvania and Hawaii were studied about 2 years after the war (Stretch et al. 1996). Of the deployed active-duty and reserve or National Guard soldiers, 8% and 9.2%, respectively, had a symptom complex suggestive of PTSD; of the nondeployed active-duty and reserve or National Guard soldiers, only 1.3% and 2.1%, respectively, had such symptoms. In an earlier study of 11,000 active-duty Gulf War soldiers conducted 6-12 months after the war, current PTSD rates were 12.9-15.5% (Stretch et al. 1996). The lower rates in the Pennsylvania and Hawaiian troops were attributed to their military occupations—support activities—which may have resulted in less exposure to traumatic events than the active-duty Army soldiers who had engaged in combat.
In a 1995-1997 survey of 9476 Gulf War-era veterans and 11,441 Gulf War-deployed veterans in all four services, Kang et al. (2003) found that 12.1% of deployed veterans and 4.3% of nondeployed veterans met the screening criteria for current PTSD using the PTSD Checklist (adjusted OR 3.1, 95% CI 2.7-3.4). The risk of PTSD increased with the severity of the stress, ranging from 3.3% in activated but nondeployed reserve personnel (minimal stress) to 22.6% in Gulf War-deployed veterans who had worn chemical protective gear, heard chemical alarms, been involved in direct combat duty, and witnessed deaths (maximal stress). In a followup to that study, Toomey et al. (2007) found that 6.2% of Gulf War-deployed veterans and 1.1% of nondeployed veterans had a diagnosis of war-related PTSD 10 years after the war (OR 5.78, 95% CI 2.62-12.74; adjusted for age, sex, ethnicity, duty type, service branch, and rank).
Ikin et al. (2004) found that a decade after the Gulf War, 5.1% of Australian Gulf War veterans had PTSD (diagnosed with the CIDI), compared with 1.7% of nondeployed Australian veterans. Few of the Australian veterans experienced direct combat; rather, their stressors were associated with the threat of combat, anticipation of attack with biologic or chemical agents, and the discomfort and isolation of deployment. Similar risks for PTSD were seen in Canadian Gulf War-deployed and nondeployed veterans (Goss Gilroy Inc. 1998). A 1998-2001 mail survey of 23,358 UK Gulf War veterans also found increased self-reports of PTSD and associated symptoms compared with nondeployed military personnel (1.0% vs 0.4%, OR 2.4, 95% CI 1.8-3.1) (Simmons et al. 2004).