After a third of veterans report being arrested, a new effort to understand why

After close to a decade serving in the Marine Corps, Ron Self could knot a rope that was strong enough to drag military vehicles across combat zones in Africa. But serving time in a prison cell years later, he couldn't get the bedsheets he'd tied together to hold.

"When I attempted to hang myself and the rope broke and I was on my knees and I realized immediately this is not -- this was not -- the solution," he told ABC News.