As soldiers return home from the conflict in Iraq, the press continues to link this war with the Vietnam War in tactical and diagnostic terms. Despite evidence that post-traumatic stress disorder may not have been as widespread as many mental health experts claimed, the debate surrounding this syndrome has been renewed with an eye toward helping soldiers from Iraq reintegrate into civilian society.

Over the next few months, 130,000 American troops will return home from Iraq. Their arrival will bring joy to their families and gratitude from the nation. It will also renew a debate over post-traumatic stress disorder. The House Veterans' Affairs Committee, for instance, has scheduled hearings on the disorder March 11, with a focus on soldiers returning from Iraq and Afghanistan.

Likewise, just as the press has spent a year comparing the invasion of Iraq to Vietnam, it has begun drawing parallels between today's troops and Vietnam veterans, who are believed to suffer from a high rate of war-related psychiatric disorders.

But as we try to help the soldiers of Operation Iraqi Freedom meld back into society, it would be a mistake to rely too heavily on the conventional wisdom about Vietnam. What is generally put forth as an established truth--that roughly one-third of returnees from Vietnam suffered psychological problems--is at best highly debatable.

Post-Traumatic Stress Disorder: Fact and Fiction

That much-cited estimate comes from the National Vietnam Veterans Readjustment Study, released in 1990 by the Veterans Administration. It concentrated on post-traumatic stress disorder, a psychiatric condition marked by disabling painful memories, anxiety, and phobias after a traumatic event like combat, rape, or other extreme threat. It found that 31 percent of soldiers who went to Vietnam, or almost one million troops, succumbed to post-traumatic stress. The count climbed to fully half if one included those given the diagnosis of "partial" post-traumatic stress disorder.

On closer inspection, however, these figures are shaky. After all, only 15 percent of troops in Vietnam were assigned to combat units, so it is odd that 50 percent suffered symptoms of war trauma. True, noncombat jobs like driving trucks put men at risk for deadly ambush, but Army studies on psychiatric casualties during the war found the vast majority of cases referred to field hospitals did not have combat-related stress. Rather, most were sent for medical attention because of substance abuse and behavioral problems unrelated to battle.

Moreover, during the years of the most intense fighting in Vietnam, psychiatrists reported that psychiatric casualties numbered between twelve and fifteen soldiers per thousand, or a little more than 1 percent. If the 1990 readjustment study is correct, the number afflicted with diagnosable war stress multiplied vastly in the years after the war. Again, it does not add up.

How to explain the postwar explosion in Vietnam cases? The frequently proffered answer is that the start of the disorder can be delayed for months or years. This belief, however, has no support in epidemiological studies. And consider the striking absence of delayed cases in long-range studies like those involving people affected by the Oklahoma City bombing. Such studies have found that symptoms almost always develop within days of the traumatic event and, in about two-thirds of sufferers, fade within a year.

It is worth noting that the concept of delayed post-traumatic stress was introduced in the early 1970s by a group of psychiatrists led by Robert Jay Lifton, an outspoken opponent of the war. They decided that many former soldiers suffered what was called post-Vietnam syndrome--marked by "alienation, depression, an inability to concentrate, insomnia, nightmares, restlessness, uprootedness, and impatience with almost any job or course of study"--and that this distinguished veterans of Vietnam from those of any other war.

While there were little data to back up the existence of this delayed syndrome, the image of the veteran as a walking time bomb was a boon to the antiwar movement, which used it as proof that military aggression destroys minds and annihilates souls. Yes, some veterans suffered the crippling anxiety of chronic post-traumatic stress disorder. But the broad-brush diagnosis of post-Vietnam syndrome also served political ends.

There are a couple of other reasons to be skeptical. For one, there is an economic incentive to claim suffering. A veteran deemed to be fully disabled by post-traumatic stress disorder could collect $2,000 to $3,000 a month, tax free. The effect of pensions was noted as early as World War I. "As men got better, the thought of losing their allowance would cause their . . . symptoms to return or new ones to appear," wrote one British psychotherapist in the early 1920s. More important, perhaps, the syndrome provides a medicalized explanation for many unhappy, but not necessarily traumatized, veterans trying to make sense of their experience.

Psychological studies have shown that people tend to reconstruct the past in terms of the present--they often exaggerate the degree of earlier misfortune if they are feeling bad, or minimize old troubles if they are feeling good. Thus it is vital that researchers corroborate the battlefield events that veterans cite as causes of their post-traumatic stress. Unfortunately, researchers on the 1990 readjustment study did not do the archival legwork to verify the trauma that the veterans reported, and the damage done is considerable. "Unless we avail ourselves of the historical archival material to verify self-reported traumatic events, we will never know how much memory distortion has infected the data base on post-traumatic stress disorder," cautions psychologist Richard McNally at Harvard University, author of Remembering Trauma. Until a better study is done, the "facts" on post-Vietnam stress are simply speculation.

Mistaken Rx for Today's Soldiers

"As psychiatrists we are urged to learn the lessons of Vietnam, but no one is sure what those lessons are," says psychiatrist Simon Wessely of King's College London. "Do the explanations for allegedly high rates lie in the jungles of Vietnam," Wessely asks, "in America's struggle to come to terms with the war, or with symptoms manufactured to fit a cultural narrative and expectation of what kinds of mental stress these veterans would experience?"

Some soldiers will return from Iraq and Afghanistan with severe psychological problems, and we must do everything in our power to help them. The vast majority, however, will be able to adjust on their own--and imposing on them the questionable legacy of Vietnam will not do them any service. As Wessely has put it: "Generals are justly criticized for fighting the last war, not the present one. Psychiatrists should be aware of the same mistake."

Sally Satel, M.D., is a resident scholar at AEI.