It sounds like the punch line of a joke: The person who went crazy was the psychiatrist.

But nobody was laughing on Friday as the US military struggled to cope with the worst mass shooting in its history.

We may never know why Nidal Malik Hasan took aim and fired at his fellow soldiers in Texas on Thursday. But the tragedy points a bright light at a problem that's been obvious for a long time: The US makes an insuffficient investment in the mental health of its soldiers.

I don't say that to make excuses for Hasan. Those who know him say he was a good soldier and a good Muslim. (Nothing in Islam supports what he's alleged to have done - for any reason. The shootings are the act of a sick man.

May 13, 2009: The US military charged an American Army sergeant on his third tour in Iraq with murder in connection with a shooting spree that left five fellow soldiers dead in a mental health clinic at Camp Liberty in Baghdad. Long-time observers of the US military say the shooting shows all the signs of a soldier pushed to the brink of insanity by repeated and consistent exposure to war. The 44-year-old Sergeant John Russell had spent many years of his life at war when he allegedly opened fire and killed five of his fellow soldiers. Russell was coming to the end of his third tour in Iraq and had also served deployments in Bosnia and Kosovo.

February 2009: The US Army said that the number of soldiers who committed suicide last year has increased for a fourth straight year. Army officials said despite an increase in funding for programs to help soldiers, they are having a hard time fighting the stigma attached to seeking professional help. At least 128 soldiers committed suicide in 2008, an increase from 2007 when a total of 115 suicides were recorded among active-duty and reserve personnel.

May 7, 2008: USA Today reported the Pentagon had illegally deployed 43,000 soldiers doctors deemed medically unfit during the first five years of the Iraq war.

April 17, 2008: A prominent research organization estimated that 300,000 of the 1.5 million US troops who have served in Iraq or Afghanistan have symptoms of post-traumatic stress disorder (PTSD) or major depression, and a similar number may have suffered traumatic brain injuries, mainly from explosions. The Pentagon welcomed the Rand Corp study, and officials say they are working on these issues.

Shad Meshad heads the National Veterans Foundation (NVF), which runs a toll-free hotline for soldiers who struggle to adjust to civilian life.

"It was tragic," he said of the Russell case in Iraq, "but unfortunately it doesn't surprise me given the way we're recycling them in and out of war zones. We are not doing a good job of treating these people as they serve two, three, or four tours in a combat zone."

Nearly 800,000 soldiers have served at least two tours in Iraq and Afghanistan.

That wasn't the case for Hasan, who was on the verge of his first deployment. But the strain of two long wars has taken a toll on the entire military, the head of the Joint Chiefs of Staff, Admiral Mike Mullen, acknowledged earlier this year.

The Russell shooting spree "does speak to me about the need for us to redouble our efforts in terms of dealing with the stress [of war], dealing with those kinds of things," he told the Associated Press.

Military critics say one problem is that commanders are evaluated based on what percentage of their companies are combat-ready. So a soldier deemed unfit for combat makes the commander looks bad. The result, they say, is military mental health care system in "where PTSD is seen as condition that can be treated in combat."

That's troubling, says the NVF's Meshad.

"If a soldier has PTSD he has no business going back to where his PTSD started," Meshad told OneWorld.net. "Individuals who are having PTSD symptoms need to have those symptoms addressed. They do not need to be in a place where more catastrophic events are going to happen."

Nov 11 is Veterans Day in the US. The 535 members of Congress will be on holiday, but when they return, perhaps they will be inspired to fund mental health care for the military at an appropriate level. Enlisted men and women being exposed to the trauma of war deserve no less.

That may not prevent another crazy act like Thursday's attack at Fort Hood. But seriously disturbed soldiers should be rare in any army, and the US government should do much more to keep them out of the line of fire.

Mike Peters is international news editor of China Daily. He can be reached at michaelpeters@chinadaily.com.cn