Stress rate revised for Vietnam vets.

Inspired by a long-standing controversy over estimates of the number of psychiatric casualties among Vietnam veterans, a research team has determined that overall, about 19 percent of those military personnel developed a serious war-related stress disorder. Furthermore, half of that group still suffered from the condition, post-traumatic stress disorder (PTSD), 11 to 12 years after the war ended in 1975, say psychiatric epidemiologist Bruce P. Dohrenwend of Columbia University and his coworkers.

The scientists reanalyzed data from a 1988 study of 1,200 Vietnam vets. That investigation found that 31 percent of the vets had developed PTSD at some time after their military service and that 15 percent had the disorder at the time of the study. Some researchers have suggested that the national study inflated prevalence rates.

Dohrenwend's group consulted military and historical records to verify vets' reports of war-zone exposure and traumatic events. The investigators also reviewed tape recordings and written records of psychiatric examinations for a representative group of 260 vets from the 1998 sample.

PTSD rates were substantially higher among vets who had been exposed to combat and other traumatic wartime events, the researchers report in the Aug. 18 Science. Up to 12 years after having survived extreme dangers, 28 percent of vets had PTSD, compared with 1 percent of vets who had had less exposure to trauma.

Dohrenwend's study demonstrates that the 1988 investigation overestimated the rate of PTSD among Vietnam vets by about 40 percent, remarks Harvard University psychologist Richard J. McNally in an editorial published with the new report.

Some PTSD investigators, such as psychiatrist Arthur Blank Jr. of Bethesda, Md., who directed the 1988 project, contend that the new study underestimates severe stress reactions in Vietnam vets.