o'byrne's life for 15 months. his deployment was the subject of the 2000 -- the 2010 documentary restrepo.returned to silly in life 11 years ago but finds it difficult to leave the war behind him. >> i loved rununning right befoe the military. i loved running inside the military. but now every time i ran outside the military, every time i started to get winded, i would start having panicked -- panic attacks. what is going on? if you are in afghanistan walking up a mountain and you are winded and can't get out of the way, you can't physically get to the next concealment spot, that would be a problem, wouldn't it? reporter: o'byrne was 22 when he was sent to fight the taliban. his mission, he believed, was to make the world a safer place, but on the ground the reality was different. >> you can't defeat an ideology with violence. you kill someone, and they have family. and now you have created two more terrorists instead of the one, and that is ad infinitum. you can do that forever. that is what fighting this kind of war is. reporter: after returning home, o'byrne battled several years to ove