For military personnel sent to war zones, seeing killing, maiming or dead bodies dramatically increases the risk of developing post-traumatic stress disorder and depression. But researchers studying service members deployed to Afghanistan and Iraq have identified another factor that may raise the risk of those psychiatric conditions by almost the same degree: a history of insomnia.In a study published Friday in the journal Sleep, scientists from the University of Pennsylvania and the Naval Health Research Center in San Diego found that sleep problems before deployment at least doubled the risk for PTSD and quadrupled it for depression.
The work could have practical applications for the military. Identifying and treating sleep problems before deployment could reduce the rate of service members returning home with mental health disorders, the researchers said.

History of insomnia raises risk for PTSD and depression in troops - latimes.com