Prior assault boosts PTSD risk after combat

NEW YORK (Reuters Health) - Men and women who were assaulted before entering military service are more than twice as likely to develop post-traumatic stress disorder (PTSD) after combat deployment, Navy researchers report.

It's estimated that as many as 1 in 10 veterans returning from the current conflicts in Iraq and Afghanistan have symptoms of PTSD. Some investigators have suggested that past stressful events can protect people from developing PTSD via "stress inoculation," while others argue that such stresses actually make people more vulnerable.

To investigate the effect of having been assaulted before combat exposure on the likelihood of developing PTSD, Dr. Tyler C. Smith of the Naval Health Research Center in San Diego and colleagues looked at 5,324 men and women participating in the Millennium Cohort study. All were in military service as of October 1, 2000, were deployed to Iraq or Afghanistan, and were free from PTSD when they entered the study.

Of the 881 women included in the study, 28 percent study had been experienced a violent or sexual assault, or both, compared to 9 percent of the 4,443 men in the study.

Overall, 13 percent of the women exposed to combat developed PTSD, while 22 percent of those who had been assaulted developed PTSD. Seven percent of the men developed PTSD, as did 12 percent of the men who had been assaulted before the study's outset.

When the researchers adjusted for level of education, age, problem drinking and other factors that could influence both the risk of developing PTSD and the likelihood of having been the victim of an assault, women with a history of assault were still 2.3 times more likely to develop PTSD. The "adjusted" PTSD risk for male assault victims was doubled.

"Though the PTSD risk conferred by combat exposure and heightened by previous life events may not be preventable, these subsets of individuals who seem to be even more vulnerable deserve closer attention from the medical community," Smith and his team conclude.

SOURCE: Epidemiology, May 2008.