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."