We don't know if post traumatic stress disorder has anything to do with this weekend's mass shooting of innocent people in Afghanistan.
But we do know the accused shooter had suffered a brain injury from a previous tour of duty.
Experts at Fresno VA's hospital are responding to a growing need for PTSD and traumatic brain injury treatments.
Many veterans who served in Iraq and Afghanistan are finding it hard to escape the demons of war.
"We went through mortar attacks on our camp. The I.E.D.'s and everything. It just became second nature to everything we were doing," said Army Sgt. Jarid Hilchey, who served two tours.
He was in Iraq when his Humvee was hit by an I.E.D. He was diagnosed with traumatic brain injury.
Even after that he went on to do a 15 month tour in Afghanistan.
"You start having dreams, hard time falling asleep, just constant memories about it. But you just think it's something natural, you don't think it's related to PTSD, you're just remembering it," said Sgt. Hilchey.
He says he didn't know anything was wrong, until he saw a doctor.