According to a new study, fewer male Vietnam veterans suffer from post-traumatic stress disorder (PTSD) than previously believed. The new finding debunks a controversial late-1980s report, which stated that one in three veterans developed the disorder.
The recent study includes strong evidence of a dose-response relationship between trauma and the disorder—the more trauma a veteran experienced while at war, the more likely he was to develop PTSD, and the more severe and persistent it was likely to be.
"War-related PTSD is very real," said Bruce P. Dohrenwend, lead author of the new report and psychiatric epidemiologist at New York State Psychiatric Institute. "This is as near as you can get to demonstrating a causal relationship."
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PTSD is an anxiety disorder sparked by exposure to a serious danger or upsetting event. People who develop PTSD may be plagued by nightmares, feel emotionally detached, be easily startled, and repeatedly relive traumatic events in their heads.
Dohrenwend's re-examined the Congressionally-mandated 1988 National Vietnam Veterans Readjustment Study (NVVRS), previously the authoritative report on Vietnam-related PTSD. Dohrenwend and his colleagues performed a new analysis of data collected for the NVVRS, combining it with information from the veterans' military records and using a different model of PTSD.
According to the new results, published in the August 18 issue of Science, 18.7 percent of Vietnam veterans developed war-related PTSD and 9.1 percent suffered from the disorder more than ten years after the war, when the NVVRS was conducted. These figures are substantially lower than the NVVRS findings of a 30.9 percent lifetime rate and a 15.2 percent rate at the time of the study.
"This study represents a significant advance in our understanding of trauma and veterans," said Harvard psychologist Richard J. McNally, who wrote a commentary on the report, also in Science.
The new numbers are lower in part because researchers excluded those whose PTSD may have been triggered by events that occurred either before or after the war, a distinction the NVVRS did not make.
Additionally, in the current study, researchers diagnosed only those veterans that displayed some social impairment as having PTSD. At the time of the NVVRS, a patient did not have to be socially impaired to receive a PTSD diagnosis.
Skeptics of the NVVRS findings argued that 30 percent of veterans could not suffer from trauma exposure when only 15 percent of American soldiers supposedly saw live combat. But in Vietnam, considered to be a "war without fronts," many more than 15 percent were in fact exposed to combat, the authors of the new study write.
Other critics held that veterans in the NVVRS study may have exaggerated or remembered events imperfectly. The recent study used military records to confirm veterans' self-reported war experiences, and found very little evidence of exaggeration or falsification.
"By and large the veterans were telling us the truth," Dohrenwend said, noting that a substantial number of veterans—about 250,000—suffered from PTSD more than a decade after the war's end.
The new, lowered prevalence statistics may discourage PTSD diagnoses and make it harder for veterans to get help, said Samuel Slaughterbeck, a Vietnam veteran with PTSD and an officer of the National Veterans Organization of America.
The Department of Veterans Affairs recently commissioned several reviews on PTSD, in part because the number of veterans receiving disability payments for PTSD has soared in recent years.
Because, like that in Vietnam, the war in Iraq is a war without fronts, Dohrenwend believes the new study may help shed light on the mental health of soldiers returning from the current conflict.
For his part, McNally doesn't see the incidence of PTSD to be declining, even with the evidence from Dohrenwend's report.
"We'll probably need to advance treatment," McNally said, "not decrease treatment."