LEEDS, Mass. — Peter Mohan traces the path from the Iraqi battlefield to this lifeless conference room, where he sits in a kilt and a Camp Kill Yourself T-shirt and calmly describes how he became a sad cliche: a homeless veteran.

There was a happy homecoming, but then an accident — car crash, broken collarbone. And then a move east, close to his wife's new job but away from his best friends.

And then self-destruction: He would gun his motorcycle to 100 mph and try to stand on the seat. He would open up whatever bottle of booze was closest. He would pull out his gun and sometimes place it in his mouth.

Peter Mohan never did find a steady job after he left Iraq. He lost his wife, he lost his friends and he lost his home, and now he is here, in a shelter.

He is 28 years old. "People come back from war different," he said.

This is not a new story in America: A young veteran back from war whose struggle to rejoin society has failed, at least for the moment, fighting demons and left homeless.

But it is happening to a new generation. As the war in Afghanistan plods on in its seventh year, and the war in Iraq in its fifth, a new cadre of homeless veterans is taking shape.

For now, about 1,500 veterans from Iraq and Afghanistan have been identified by the Department of Veterans Affairs. About 400 of them have taken part in VA programs designed to target homelessness.

But advocates for homeless veterans use words like "surge" and "onslaught" and even "tsunami" to describe what could happen in the coming years.

Some veterans advocates say there are some factors particular to the Iraq war, like multiple deployments and the proliferation of improvised explosive devices, that could be pulling an early trigger on stress disorders that can lead to homelessness.

"There's something about going back, and a third and a fourth time, that really aggravates that level of stress," said Michael Blecker, executive director of Swords to Plowshares," a San Francisco homeless-vet outreach program.

Marine Corps veteran Mike Lally, 26, thinks back to the long stretches in the stifling Iraq heat, and about the day insurgents killed the friendly shop owner who sold his battalion Pringles and candy bars.

He thinks about crouching in the back of a Humvee watching bullets crash into fuel tanks during his first firefight. But Lally is fairly sure that what finally cracked him was the bodies. Unloading the dead from ambulances and loading them onto helicopters. That was his job.

"I guess I loaded at least 20," he says. "Always a couple at a time. And you knew who it was. You always knew who it was."

It was in 2004, when he came back from his second tour in Iraq, that his own bumpy ride down began.

He would wake up at night, sweating and screaming, and during the days he imagined people in the shadows. He became an alcoholic, lost his job and was booted out of the house by his wife.

These days he pads around in an old T-shirt and sweats at a Leeds shelter called Soldier On, trying to get sober and, perhaps, get his home and family and life back.

"I was trying to live every day in a fog," he said. "I'd think I was back in there, see people popping out of windows. Any loud noise would set me off. It still does."

John Driscoll, vice president for operations and programs at the National Coalition for Homeless Veterans, said the VA has more than 200 veteran adjustment centers to help ease the transition back into society, and notes the existence of more than 900 VA-connected community clinics nationwide.

"We're hopeful that five years down the road, you're not going to see the same problems you saw after the Vietnam War, if we as a nation do the right thing by these guys," he said.