The Pentagon has decided that it will not award the Purple Heart, the hallowed medal given to those wounded or killed by enemy action, to war veterans who suffer from post-traumatic stress disorder because it is not a physical wound.

The Purple Heart will be given for physical wounds only. (Chris Ramirez for The New York Times) The decision, made public on Tuesday, for now ends the hope of Iraq and Afghanistan veterans who have the condition and believed that the Purple Hearts could honor their sacrifice and help remove some of the stigma associated with the condition.

The disorder, which may go unrecognized for months or years, can include recurring nightmares, uncontrolled rage and, sometimes, severe depression and suicide. Soldiers grappling with PTSD are often unable to hold down jobs.

In May, Defense Secretary Robert M. Gates said awarding Purple Hearts to such service members was "clearly something that needs to be looked at," after he toured a mental health center at Fort Bliss, Tex.

But a Pentagon advisory group decided against the award because, it said, the condition had not been intentionally caused by enemy action, like a bomb or bullet, and because it remained difficult to diagnose and quantify.

"Historically, the Purple Heart has never been awarded for mental disorders or psychological conditions resulting from witnessing or experiencing traumatic combat events," said Eileen Lainez, a Pentagon spokeswoman. "Current medical knowledge and technologies do not establish PTSD as objectively and routinely as would be required for this award at this time."

One in five service members, or at least 300,000, suffer from post-traumatic stress disorder or major depression, according to a Rand Corporation study in 2008.

For some soldiers suffering from the disorder, the historical distinction between blood and no blood in an injury fails to recognize the depths of their mental scars. A modern war - one fought without safe havens and with the benefit of improved armor - calls for a new definition of injuries, some veterans say.

Kevin Owsley, 47, who served in the Ohio National Guard in 2004 as a gunner on a Humvee and who is being treated for PTSD and traumatic brain injury, said he disagreed with the Pentagon's ruling.

Unable to hold a job, Mr. Owsley supports his family on disability payments. This week he told his Veterans Affairs doctor he was fighting back suicidal impulses, something he has struggled with since his return. "You relive it every night and every day," he said. "You dream about it. You can see it, taste it, see people getting killed constantly over and over."

"It is a soldier's injury," he said, angrily, in a telephone interview on Wednesday.

But many soldiers do not feel that way. In online debates and interviews they expressed concern that the Purple Heart would be awarded to soldiers who faked symptoms to avoid combat or receive a higher disability rating from the Department of Veterans Affairs.

"I'm glad they finally got something right," said Jeremy Rausch, an Army staff sergeant who saw some of the Iraq War's fiercest fighting in Adhamiya in 2006 and 2007. "PTSD can be serious, but there is absolutely no way to prove that someone truly is suffering from it or faking it."

The Purple Heart in its modern form was established by Gen. Douglas MacArthur in 1932. Some 1.7 million service members have received the medal, and, as of last August, 2,743 service members who served in Afghanistan and 33,923 who fought in Iraq had received the award.

The medal entitles veterans to enhanced benefits, including exemptions from co-payments for veterans hospital and outpatient care and gives them higher priority in scheduling appointments.

The Pentagon left open the possibility that it could revisit the issue.

But a Pentagon-supported service group, the Military Order of the Purple Heart, has strongly opposed expanding the definition to include psychological symptoms, saying it would "debase" the honor.

"Would you award it to anyone who suffered the effects of chemicals or for other diseases and illnesses?" John E. Bircher III, director of public relations for the group, said Wednesday. "How far do you want to take it?"

Post-traumatic stress disorder was first identified during the Vietnam War and has gradually been accepted as a serious psychological problem for some who experience violence and fear.

Dr. Barbara V. Romberg, a psychologist in Bethesda, Md., and founder of Give an Hour, which offers mental health services to troops and their families, said that she and many other psychologists believed the discussion of Purple Hearts had brought more attention to post-traumatic stress disorder and the seriousness of psychological wounds suffered on the battlefield.

"We're working to normalize post-traumatic stress as an understandable human consequence of war that can result in very serious damage to some people's lives, and they deserve honoring for that," she said.

"But I don't want to be so quick to condemn the decision," she added.

Many have post-traumatic stress, but only some develop a serious lasting disorder; in both cases, she said, "people deserve to be honored in some way for the injury they received in combat."

After years of criticism for ignoring the problem, the Defense Department and the Veterans Administration have bolstered their capacity to diagnose and treat PTSD, and those with serious cases may receive substantial disability benefits. Some of those suffering from severe traumatic brain injuries qualify for a Purple Heart because they required medical treatment.

But in its decision not to extend Purple Hearts to PTSD sufferers, first reported Tuesday by Stars and Stripes, the Pentagon said part of the problem stemmed from the difficulty in objectively diagnosing the disorder.

That decision was made in November. It was not clear why the Pentagon did not announce the decision then.

There have been recent changes in awarding Purple Hearts. The criteria was expanded in 2008 to include all prisoners of war who died in captivity, including those who were tortured. "There were wounds there," Mr. Bircher said.

"You have to had shed blood by an instrument of war at the hands of the enemy of the United States," he said. "Shedding blood is the objective."