Longer Military Deployment Increases Risk of MH Problems

Americans often hear about the psychological demands on U.S. soldiers, whose tours of duty in Iraq have been extended from 12 to 15 months. They are not alone. New research shows that longer tours of duty appear to take their toll on troops from other countries too, according to an ongoing study of British forces by the King's Centre for Military Health Research at King's College London.

Operational tempo—the number and frequency of deployments—is a normal part of a military career, but rising demands for military operations may also increase stress on troops and their families. Commanders try to balance deployment with periods at home to allow troops to recover from the stresses of war and maintain family ties, with mixed success. The U.S. Senate in September rejected legislation requiring the Pentagon to allow troops a period at their home bases equal to time on deployments.

Military authorities in the United Kingdom have set “harmony guidelines” for how often and how long army troops can be deployed on operations—a six months' tour of duty followed by 24 months at home during any 36-month stretch. Thus a unit might be deployed for a maximum of 12 months out of three years.

Roberto Rona, M.D., Ph.D., a professor of public health, and colleagues surveyed a randomly chosen sample of 5,547 members of the British Army, Royal Navy, Royal Marines, and Royal Air Force to determine the effects of operational tempo on mental health. They measured psychological distress, posttraumatic stress disorder (PTSD), fatigue, physical symptoms, and use of alcohol. All the surveyed troops had taken part in at least one deployment in the previous three years, during which British forces served in conflicts or peace missions in Afghanistan, Bosnia, Kosovo, Macedonia, Iraq, Kuwait, and Sierra Leone.

The response rate was about 60 percent. Demographically, nonresponders were more likely than responders to be younger, male, from enlisted ranks, and nonwhite, said Rona in an interview with Psychiatric News.“ However, it is fair to say that we have more difficulty in obtaining a questionnaire completion from subjects who left the services and had a civilian address rather than a military address.”

Parallel Study

A smaller parallel study published last year by the same team found little overall difference on most characteristics at baseline between those who subsequently responded or did not respond at follow-up, although the baseline prevalence of PTSD and alcohol misuse were higher in nonresponders, Rona said.

Long deployments—those of 13 months or more—were associated with higher prevalence of psychological symptoms, problems at home, and severe alcohol problems, wrote Rona and colleagues in the September 22 BMJ. The study found little association between mental health problems and the number of deployments.

In addition, troops deployed for longer-than-expected times were more likely to reach cutoff scores for PTSD as measured by the National Center for Posttraumatic Stress Disorder Checklist, a result that held up even after adjustment for demographic factors and service branch. “Psychological distress” was measured using the 12-item General Health Questionnaire.

American Troops Also Concerned

The U.S. Army's Mental Health Advisory Team IV survey, completed in November 2006, found that American troops were also very concerned about long deployments and an uncertain return date.

“Adherence to a clear and explicit policy on duration of each deployment may have beneficial effects on mental health,” Rona and colleagues said.

Deployment alone did not account for the adverse effects found in the survey. A soldier's role in a theater of operations, time spent in a forward area (a possible indicator of combat exposure), and problems at home accounted for much of the association with PTSD.

“Role during deployment is clearly a feature of deployment, thus not a confounder,” Rona told Psychiatric News. Prolonged deployment increased the effect among those with a combat role more than those with other military jobs, like combat support or service.

He also pointed out that his study was based on all British military services, rather than combat troops alone, which has been the focus of research by Charles Hoge, M.D., of the Walter Reed Army Institute of Research, and others, on U.S. troops who have served in Iraq or Afghanistan. Those studies have found higher rates of mental problems on return from deployment than did the British study.

“It is fair to say that the Americans experienced a greater combat intensity at the time, but we doubt that the difference in combat intensity totally explains the differences in PTSD rates between the two forces,” said Rona. “The Americans tend to send younger personnel for a longer period of time who were less accustomed to deployment compared to the British.”

While previous studies have found that duration of deployment is associated with psychological distress, this is the first to look at deployment over three years, wrote Rona and colleagues. Their findings provide a“ tangible measure of overstretch”—the military term for what happens when “smaller forces are carrying out an increasing number of operational duties worldwide.”

Deployment is an inevitable part of military life and cannot be considered alone, said an accompanying BMJ editorial.

“However, it is the nature of the deployment experience—the 'toxic' exposures—including traumatic events, loss of attachments, and psychological and physical demands that increase the risk of mental illness,” wrote Robert Ursano, M.D., a professor; David Benedek, M.D., an associate professor; and Charles Engel, M.D., an associate professor at Center for the Study of Traumatic Stress, part of the Department of Psychiatry at the Uniformed Services University of the Health Sciences. “Perhaps most importantly, Rona and colleagues have shown that the Iraq war is not without its costs—both to the health of those deployed and eventually to the health care system—and that these same costs are related to duration of exposure.”

“Mental Health Consequences of Overstretch in the UK Armed Forces” is posted at<www.bmj.com/cgi/content/full/335/7620/603>; the editorial is posted at<www.bmj.com/cgi/content/full/335/7620/571>.▪