Stress from combat changes activity in soldiers’ brains, compromising their ability to focus attention, researchers in the Netherlands said.
Dutch veterans who served with NATO in Afghanistan showed declines in working memory and their capacity to sustain attention in tests done about a month and a half after they arrived home, according to an imaging study reported today in the Proceedings of the National Academy of Sciences. The structural changes mostly disappeared 18 months after the soldiers ended active duty, the researchers found.
Studies have shown that chronic stress increases the likelihood of psychiatric illness, prompting some nations to boost post-combat evaluations. U.S. President Barack Obama signed an executive order Aug. 31 adding suicide prevention efforts for veterans and expanding access to mental-health care as returning soldiers face an unemployment rate more than 3 percentage points higher than the rest of the population.
“If you have been stressed for a long time, more or less continuously, there are some remnants,” said Guido van Wingen, a neuroscientist at the Brain Imaging Center in Amsterdam who helped to write the study, in a telephone interview. “But the brain is almost entirely capable of restoring if you give people enough time to go on with their normal lives. This should be optimistic for everyone returning from deployment.”
The study examined the differences between 33 healthy Dutch soldiers sent to Afghanistan as part of the North Atlantic Treaty Organization and 26 peers who were never deployed. They had matched their non-deployed peers on brain scans and memory tests taken before they left for war.
Magnetic resonance imagining scans of the blood flow in the brains showed those who had been deployed had significantly less activity from the control group in the midbrain, a region important for voluntary movement.
While the combat veterans’ brains reverted to look more like those in the control group a year and a half later, not all of the changes were gone. Aberrations remained in the connections between the midbrain and the prefrontal cortex, the part of the brain behind the forehead that helps moderate behavior and focus attention.
“Those people may be at increased risk for cognitive issues when they’re stressed again, or if they’re redeployed,” van Wingen said.
The 2.6 million people who served the U.S. in Afghanistan and Iraq are struggling with an unemployment rate that reached 12.1 percent last year, according to the Bureau of Labor Statistics. Non-veterans had an unemployment rate of 8.7 percent.