One in 10 veterans of the Vietnam war who returned from that conflict are still suffering from post traumatic stress disorder 40 years on, suggesting for some it may be a life-long burden, a study has found.

The study by the National Vietnam Veterans Readjustment Survey is evidence that of the almost 480,000 thousand veterans diagnosed with PTSD, most have learned to cope but some have not and will be dealing with its aftereffects their whole lives.

The research is an updating of a milestone study that took place in the 1980s, when some 15 percent of veterans of Vietnam were found to have some level of the disorder.

The new study strongly suggests that for some, PTSD with its disabling flashbacks, invasive memories, sleep problems and major depression has become a chronic affliction.

"They develop a very difficult-to-treat form of PTSD," said Dr. Charles Marmar, a New York University psychiatrist involved in both the original and the follow-up study.

The Department of Veterans Affairs funded both studies.

Early death has long been associated with PTSD, and the new study confirms that among Vietnam veterans, those diagnosed with the disorder in the earlier survey were twice as liable as those without to have died between then and now.

While natural causes claimed some, a significant proportion were the victims of accidents, injuries, suicide or homicide, the researchers found.

There was also a higher-than-normal incidence of cancer, with the researchers noting that veterans with PTSD tended to be heavy smokers.

The new conclusions are almost certain to have a significant impact on the treatment of post-traumatic stress and decisions regarding disability-benefit programs in the foreseeable future, the study authors wrote.

Those issues are likely to remain in the forefront of veterans' concerns following the wars fought in Afghanistan and Iraq; a 2006 study found PTSD in around 16 percent of service personnel who took part in ground combat in Iraq.

For the new survey researches were able to track down almost 80 percent of those taking part in the 1980s study, conducting phone interviews and providing questionnaires to be filled out.

"This study shows us what the road ahead is going to look like," said Marmar, who is chairman of psychiatry at the university's Langone Medical Center. "A significant number of veterans are going to have PTSD for a lifetime unless we do something radically different."

ⓒ 2021 TECHTIMES.com All rights reserved. Do not reproduce without permission.