Iraq duty linked to mental changes

A large study of Army troops found that soldiers recently returned from duty in Iraq were highly likely to show subtle lapses in memory and inability to focus, a deficit that often persisted for more than two months after they arrived home, researchers are reporting today.

But the returning veterans also demonstrated significantly faster reaction times than soldiers who had not been deployed, suggesting that some mental abilities had improved.

The slight deficit, often unnoticed by the soldiers, could make it difficult for some of them to learn and remember information as quickly as they are accustomed to, the authors said. These lapses are more common but less disabling than emotional reactions to combat like depression or post-traumatic stress disorder, the researchers said, and in many cases probably reflect a natural adaptation to life in Iraq, with the reaction time strengthening at the expense of some other mental functions.

"We're talking about a level of change that is not alarming and shouldn't send people running to the doctor but changes that some may notice when they are trying to perform in very demanding contexts" like a challenging civilian job, said the lead researcher, Jennifer J. Vasterling of the Southeast Louisiana Veterans Health Care System and Tulane University.

The study, appearing in The Journal of the American Medical Association, is the first to track carefully such changes in mental functioning over time in soldiers who deployed to a war zone and those who did not.

Researchers tried to measure similar changes in troops after the Persian Gulf War of 1991. Many of those veterans reported chronic problems with concentration, and suspected that they had been exposed to toxic nerve gases that might have been a cause. But investigators had too little information about them from before they went to war to make meaningful comparisons.

Dr. Andy Morgan, a psychiatrist at Yale, said the new findings, when further tracked over time, could help doctors predict which soldiers will adapt quickly to civilian life and which will have chronic problems adjusting. "This kind of data should help us find early markers of trouble," Morgan said, "and help us learn how to intervene if someone is headed for pathology."

The research team led by Vasterling administered a battery of mental tests to 654 male and female soldiers who served in Iraq at various times from April 2003 to May 2005. The tests, more than 20 in all, were given before and after deployment, and included one in which participants had to pay close attention to a computer screen as letters flashed by, waiting to flag each F they saw. In another test, they were asked to memorize simple diagrams and try to recreate them 30 minutes later.