This allocation of experience to identity isn't just true for symptoms of PTSD. As symptoms faded, it became clearer to me how much of my personal identity was shaped by combat.
Before 2001, the suicide rate among soldiers was lower than among civilians. Those totals both increased during the war years, but the gap became smaller. In 2012, 350 active-duty troops committed suicide.
Cook's distress never brought him to that level, but instead sent him back to war.
"When we came home, you're looking for something to kind of fill that void and there's nothing in normal civilian life where you can find that satisfaction," he said.
Cook said he surprised himself with how quickly spending time away from the war let it slip from his mind even though it was a life-changing experience he didn't want to forget.