According to a study which has looked at how U.S. soldiers fared following time spent on duty in Iraq, has found that feeling confused, having difficulty concentrating and memory lapses were quite common.
The study compared the mental capabilities and emotional states before and after deployment, in a sample group of 961 active-duty soldiers' with a group of 307 soldiers who did not serve overseas.
They found that while the majority of veterans may not be be troubled with the flashbacks and depression associated with post-traumatic stress disorder, many returning soldiers do experience some unwelcome psychological changes.
The study by Jennifer Vasterling of Tulane University School of Medicine, found there were often "subtle" changes in mental function among a sample of 654 U.S. Army veterans who had spent a year in Iraq.
Almost all reported being shot at, and two-thirds witnessed people being wounded or killed, and Vasterling says these experiences affected concentration, learning and memory and could not be put down to a pre-existing dysfunction.
Many of the veterans exhibited quicker reaction times and the researchers say this was a result of the "flight or fight" responses perfected in war.
A report by the U.S. Government Accountability Office in May found more than six percent of army soldiers who served in Iraq or Afghanistan were considered at risk for developing post-traumatic stress disorder, but only 22 percent of those at risk were evaluated.
According to another study this year as many as one in ten U.S. soldiers who served in Iraq suffered from post-traumatic stress, a disorder that can lead to nightmares, flashbacks and delusional thinking.