Temple, Texas ? After spending three months in Iraq, it’s not memories of the 120-degree heat or sounds of explosions that haunt psychiatrist Paul Hill.

It’s the soldiers: a young man who showed up at Hill’s makeshift office with his uniform and boots still splattered with his friend’s blood, another shaken after seeing his friend decapitated during a convoy bombing.

Hill said one commander told him he felt an incredible sense of guilt because his troops had been injured three times in attacks in one week, but he kept going on missions — although he vomited before each one.

Hill said he was a bit surprised by his sometimes tearful reactions to their stories. After all, he thought he had seen it all in his 71 years — from his 20 years in the Army, including a year in Vietnam, to working about 30 years as a psychiatrist, sometimes treating older veterans.

“People over here have no idea how much stress these guys are under,” said Hill, who returned to central Texas in early November.

Going to Iraq was not something Hill initially planned. A postcard delivered from the military last year asked retired doctors to volunteer their service. He thought someone had made a mistake — that he was too old, even for a noncombat role.

When he was told that age didn’t matter, he still didn’t sign up right away. He carried the folded card in his pocket for months, struggling with the decision to become part of something he had grown to deeply oppose.

“I think it was a big mistake (going to war), but it isn’t the soldiers’ fault,” Hill said. “They didn’t ask for it, but they’re over there, and the soldiers need some help. I thought I could help them.”

So Hill signed up for a year of active duty, serving the first three months in Iraq. He will work the next nine months at Fort Hood in Killeen, near San Antonio, counseling soldiers at the Darnell Army Community Hospital.

The general age limit in the Army is 55, but that limit does not apply to senior officers or volunteers, said Lt. Col. Bryan Hilferty, an Army spokesman. The oldest people serving in Iraq are volunteer doctors, but the Army cannot track who is the oldest, Hilferty said.

Twenty-eight volunteer doctors have served in Iraq since the war began, and nine of those remain on active duty, said Jaime Cavazos, a spokesman with U.S. Army Medical Command.

Hill had to pass physical and mental exams, different from those for combat troops. Aside from slightly elevated blood pressure and prostate problems, he was in good shape.

He began his stint at the U.S. Army’s Camp Cuervo in southeastern Baghdad, where he was the only full colonel.

Hill counseled soldiers in his office and prescribed medication, mostly antidepressants, he said. Aside from combat, soldiers talked to him about their worries: what was going on back home, whether their spouses were cheating on them, whether their children were OK.