Effects of Combat Stress May Not Last as Long as Thought

TUESDAY Aug. 30, 2011 -- The intense combat stress experienced by soldiers deployed to Iraq, Afghanistan or other war-torn countries may prime their brains for the development of post-traumatic stress disorder (PTSD), but new research suggests these changes don't last as long as previously thought.

PTSD is an anxiety disorder that develops after witnessing or surviving a traumatic event. Symptoms may include vivid flashbacks of the event, edginess, sleeping difficulties including nightmares and/or avoidance of any situation that may remind you of the trauma. These symptoms can appear at any time after the trauma.

The amygdala is the part of the brain where strong emotions such as anger or fear arise. Researchers used functional MRI scans to measure activity in this region of the brains of 23 soldiers who were sent to Afghanistan for four months. They compared the results of these scans to those of 16 soldiers who were not sent to Afghanistan before deployment, shortly after deployment and again 18 months later.

All soldiers performed a face-matching task in which they matched angry or fearful faces in response to visual stimuli during the brain scan. The amygdala lit up on the scans shortly after deployment among soldiers sent to Afghanistan, compared to those who were not. However, there were no differences in amygdala function between the two groups of soldiers 18 months after returning.

"These changes occur in healthy soldiers and take up to a year to normalize to a pre-deployment state, suggesting that the changes observed shortly after combat reflect an adaptation to the dangerous environment they are exposed to," explained study author Dr. Guido van Wingen of the Donders Institute for Brain, Cognition and Behavior at Radboud University Nijmegen in Nijmegen, the Netherlands. The research appears online Aug. 30 in the journal Molecular Psychiatry.

"These changes in brain functioning are the consequence of stress exposure, and it might turn out that brain imaging several months to a year after deployment could show whether a soldier's brain [normalizes]..., which could be a first indication for a potential need for additional care," he said.

Dr. Alan Manevitz, a psychiatrist with Lenox Hill Hospital in New York City, said that it may help explain why some people bounce back after a traumatic event, and others do not.

Some amygdalas may simply be more resilient that others, he explained. "This is one potential biologic basis of resilience," he said. Many questions remain, he noted, such as, "If you are constantly exposed to traumatic events during combat or even through repetitive flashbacks, are you putting your brain at risk?"

Treatment for PTSD involves psychotherapy plus medication. "We want to help people safely revisit their memories in the present without living the trauma," he said.

More information

Visit the U.S. National Institute of Mental Health for more on PTSD.

Posted: August 2011


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