The History of PTSD

"I don't know any soldiers or Marines who aren't students of history to some degree," he says. "When World War I was happening, there were still a lot of people walking around in this country who had fought in the Civil War." He adds that having PTSD doesn't mean your military service didn't also make you better in a lot of ways. "'PTSD' is like a rain cloud that hovers over veterans,' David Petraeus tells CNN's John Sutter.