The researchers also found that soldiers who had been exposed to more combat while in Iraq had quicker reaction times than those who saw less combat.
"We think a lot about the emotional impact of war, but what this study demonstrates is that as stress responses go on longer, their impact widens," Vasterling said. "When the stress reactions were new, they did not yet affect cognitive functioning."
However, as soldiers endured the stress of having been to war and any disruption it might have caused, chronic stress started causing other problems in addition to emotional distress, Vasterling said. "We see that with health and other sorts of quality of life indices among people who have suffered post-traumatic stress disorder for long periods of time," she said.
In this case, cognitive functioning might also be a window into the biology of the brain, Vasterling noted.
"We know that the brain responds in certain ways to stress, but then usually returns to its normal state. However, if these neurobiological changes go on for too long, they can overtax the system." she said.
Therefore, long term changes in attention and other cognitive processes might indicate that the brain's biology is becoming increasingly reactive, which can eventually take a toll on health, Vasterling said.
"Even the beneficial change of quicker reaction times might mean that the soldier is in a perennial 'action-ready' mode, which is great in the war zone, but can get taxing if it goes on too long," she said.
Cognitive processes such as attention are also important for everyday life, Vasterling said. "Being able to sustain concentration helps you function
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