PARK CITY — Miguel "Chin" Delgado balanced on a cable just above the ground, trying to explain to a group of fellow combat veterans about war wounds hidden inside his head.

With arms outstretched, fellow GIs listened intently as they stood just inches away from him, ready to catch him if he fell as he talked about obstacles and remedies associated with his post-traumatic stress disorder (PTSD).

After deployment to Iraq, it's estimated that about one-third of all soldiers and Marines and about half of National Guard members return with some form of PTSD or traumatic brain injury, according to a Pentagon study.

Beginning today, the Army will start a program to educate more than 1 million soldiers within 90 days that mild traumatic brain injuries, or concussions, and PTSD are serious and soldiers should seek treatment. The program is designed to teach soldiers to recognize symptoms in themselves and others and to learn about available treatment.

In groups of 40, soldiers will receive a one-hour class on brain injuries and stress.

But Tuesday in the program of a nonprofit group, on the outskirts of Park City, about 20 veterans from the Iraq, Afghanistan, Gulf and Vietnam wars took turns one by one on the "hanging vines" at the National Ability Center's challenge course.

The nonprofit group Wounded Warrior Project brought them here from six states this week to deal with their PTSD as part of Project Odyssey.

First stop on the course was the vines, where veteran Marines and soldiers held onto ropes while walking the length of a raised cable. There, they talked about how anger, depression, drugs, alcohol, guilt, gambling and other people's ignorance about PTSD hold them back from leading a more normal life.

"I need to work on slowing down," Delgado said a moment later. He was referring to an obsessive-compulsive disorder that at times controls his life.

Delgado, 45, served four combat tours, including Iraq and Afghanistan, with the Marines as a Navy medical corpsman. For 13 years, the California man was looked upon as a "healer" in his military role. But he felt that if he talked about his own psychological problems, then he would lose the confidence of those he was trying to help.

Now, however, Delgado wants to support junior veterans who are learning to confront their own PTSD.

"I think it's important for young people to know, it's not just their generation," he said.

Zach Dunn, 23, a Marine, was with his platoon when they invaded Fallujah, Iraq, in late 2004. In that battle, about 50 U.S. troops and a dozen Iraqi military members were killed, as well as about 1,300 insurgents.

These days, "after seeing the stuff I've seen," Dunn, of Missouri, said he deals with depression, uncontrollable shaking, anger, anxiety and guilt, over not being able to serve another tour in Iraq during the next year because of his own injuries.