Four decades after the Vietnam War, 11% of its veterans still suffer from post-traumatic stress disorder, according to new research suggesting that for some people it is a condition unlikely to ever go away.
The findings, presented Friday at a meeting of the American Psychological Assn., provide a rare look at the long-term course of PTSD in veterans.
The research updates a landmark study conducted in the 1980s, when researchers found that 15% of Vietnam veterans had the disorder. Despite the passage of 25 years and the increasing availability of effective treatments for PTSD, the picture remains much the same.
"People who develop PTSD, if they are going to recover, they tend to recover in the first months or years," said Dr. Charles Marmar, a psychiatrist at New York University who worked on the original study and the follow-up. "For everybody else it is very chronic."
Some experts not involved in the research suggested the new estimate is too high, because it relied on a standardized questionnaire to assess veterans rather than a structured clinical interview that is considered the gold standard for diagnosing the disorder.
When the researchers used the interview method to assess a subset of veterans in the study, the PTSD rate fell to 4.5%.
“How one assesses PTSD affects one’s estimate of its prevalence,” said Richard McNally, a Harvard psychologist who believes the disorder is overdiagnosed.
The original research, known at the National Vietnam Veterans Readjustment Study, included 1,632 veterans who had been deployed and 716 others who served during that era but never went to Vietnam.
Based on that sample, researchers estimated that 31% of Vietnam veterans had suffered from PTSD at some point in their lives, but that by the late 1980s about half no longer did.
For the new study, which was funded by the Department of Veterans Affairs, the authors tracked down the old research subjects.
More than 500 had died. An analysis estimated that the death rate for veterans who served in the war was roughly 17% and not statistically different than the rate for veterans who did not go to Vietnam. Death rates from cancer and heart disease — the biggest killers — did not differ either.
PTSD has long been associated with early death, so researchers were not surprised to find that among veterans who deployed to Vietnam, those who had the disorder in the 1980s were twice as likely as those without it to be dead today.
Roughly 1 in 4 had died. Their death rate from cancer was particularly elevated, possibly because those with PTSD are more likely to smoke.
Of the 1,839 veterans from the original study who were still alive, 1,450 participated in the new research.
"The majority of people, even those in high combat, successfully adjust," to civilian life, Marmar said.
The study found that certain groups face an increased risk of developing PTSD: high-school dropouts, minorities, those who engaged in killing and those who were very young when they served.
The biggest question emerging from the study is why more veterans did not get better over the last 25 years.
The researchers did not ask veterans about their treatment histories or examine their medical records. In clinical trials of PTSD treatments, veterans tend to show less improvement than rape victims and other patients.
Patricia Resick, a psychologist and PTSD expert at Duke University, suggested that many veterans have mild cases and choose to live with the disorder rather than seek treatment.
Some haven't come to terms with losing friends in the war. "They hold on to the idea that if I let go of my PTSD I will be dishonoring my friend," Resick said.
Other researchers have suggested that the VA disability system works at cross purposes with treatment.
"If we pay people significant amounts of money, tax-free, for having flashbacks, nightmares and startle reactions, it makes it harder to engage them in treatment," Marmar said.