How Afghanistan war changed U.S. soldier's life

A court martial in North Carolina that ended this week illustrates how the war in Afghanistan changed the life of one American soldier. As CBS News national security correspondent David Martin reports, the serious wound the sergeant suffered on the battlefield proved to be only the beginning:

After 21 years in uniform, most of it in Special Forces, Sgt. First Class Andrew McCaffrey is a broken soldier.

"I've been stripped of my Special Forces credentials and now I have basically a very low-level job," he said.

Eight years ago in Afghanistan, McCaffrey lost his right hand to a defective grenade. He fought a medical discharge, learned to shoot again, and became the first soldier to lose part of an arm and return to a war zone three more times to Afghanistan. He never found glory there, just the daily grind of military operations, but even so he seemed the epitome of perseverance.

"Being a soldier is a hands-on job," Martin asked.

"Yes sir, it is," said McCaffrey.

"And you're down to one hand."

"No, I'm not," said McCaffrey. "One just works differently than the other."

But once he was home, McCaffrey's perseverance turned to anger.

In an army document, his commanding officer detailed "multiple violent outbursts." He was described as "...a significant risk for suicide and homicide" and said to have poor insight, judgment and impulse control, and "appears to also have anti-social personality disorder."

McCaffrey had gone from being a poster boy for rehabilitation to a problem child.

"Sometimes your own worst enemy? Martin asked.

"Yeah, sometimes," McCaffrey said. "My mouth could get me in some trouble. I won't deny that."

It was his mouth that got him confined to a state psychiatric hospital for four days.

"'If you don't stop busting my chops, I'm going to go home and blow my brains out because you're driving me crazy.' That was the statement I made," he said.

McCaffrey insists he wasn't serious. "I would never kill myself because I would not give certain people the satisfaction. It's that simple."

John Nickerson, McCaffrey's attorney, said: "He is not the most pleasant person in the world. He is abrasive. He is direct. He is not gentle in any way."

Nickerson has been McCaffrey's representative since an incident in May 2009 caught on video. That's McCaffrey in the camouflage shorts at a gas station, going toe-to-toe with a hulking ex-con. It's not shown, but McCaffrey pulled a knife, inflicting a small wound, which required no stitches.

"I utilized the force that I deemed necessary to protect myself," he explained.

The district attorney's office dropped the case for lack of evidence, but the army court-martialed him on a litany of charges: assault, obstruction of justice, disobeying an order, carrying a concealed firearm, lying to a superior, driving under the influence, even missing a mental health appointment.

Nickerson believes there's a simple explanation for McCaffrey's behavior -- traumatic brain injury. "You just need to extend your arm, look at the palm of your hand. That's how far away from Sgt. McCaffrey's brain the hand grenade was when it exploded."

Whatever broke McCaffrey -- his war wound or his own personality -- he's leaving the army. The career of a soldier who served more than two years in Afghanistan came to an ignominious end this week. He was found guilty of obstruction of justice and carrying a concealed firearm and was demoted one rank, which will cost him $300 a month in retirement pay.