The study has implications for the future care of veterans of the Iraq and Afghanistan wars.
The study by Dr. Charles Marmar, of the New York University Langone Medical Center, and colleagues estimates that around 15-17% of war veterans have had post-traumatic stress disorder (PTSD) at some point in their lifetime.
The authors conclude there is an estimated 271,000 Vietnam veterans presently living with full PTSD, a third of whom have current major depressive disorder.
The authors' National Vietnam Veterans Longitudinal Study builds on the National Vietnam Veterans Readjustment Study (NVVRS), which ran from 1984 through 1988.
Of the 1,839 veterans from the original study, 1,450 (78.8%) participated in at least one phase of the new study, which ran from July 2012 to May 2013.
The prevalence among male war-zone veterans for a current PTSD diagnosis varied by definition:
- 4.5% for a current PTSD diagnosis, based on the clinician-administered PTSD scale for the fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" ("DSM-5")
- 10.8% against that assessment plus subthreshold PTSD (meeting some diagnostic criteria).
- 11.2% based on the PTSD checklist for "DSM-5" items for current war-zone PTSD.
Among female veterans, these estimates were, respectively: 6.1%, 8.7% and 6.6%.
Of the veterans with current war-zone PTSD, some 36.7 also had major depression.
Other estimates were that about 16% of war-zone Vietnam veterans reported a rise of more than 20 points on a PTSD symptom scale; 7.6% reported a fall of the same size on the scale.
Of this latter finding, the study authors say:
"An important minority of Vietnam veterans are symptomatic after 4 decades, with more than twice as many deteriorating as improving."
In an editorial article published in the same issue of the journal, Dr. Charles Hoge, of the Walter Reed Army Institute of Research in Silver Spring, MD, writes:
"This methodologically superb follow-up of the original NVVRS cohort offers a unique window into the psychiatric health of these veterans 40 years after the war's end.
No other study has achieved this quality of longitudinal information, and the sobering findings tell us as much about the Vietnam generation as about the lifelong impact of combat service in general, relevant to all generations."
"The study is of vital importance to subsequent generations of war veterans and underscores medical service needs for PTSD and related comorbidities extending decades after service," the editorial concludes.