Thousands of veterans of the Vietnam War continue to experience posttraumatic stress disorder tied to war zone experiences that occurred 40 years ago, a new study published in JAMA Psychiatry shows.

“An important minority of Vietnam veterans are symptomatic after 4 decades, with more than twice as many deteriorating as improving,” reported Dr. Charles R. Marmar and his coinvestigators in the National Vietnam Veterans Longitudinal Study (NVVLS) (JAMA Psychiatry 2015 July 22 [( doi:10.1001/jamapsychiatry.015.0803 ]).

The NVVLS, a follow-up of the original the National Vietnam Veterans Readjustment Study (NVVRS), found that about 271,000 living Vietnam veterans who were deployed into active war zones currently experience PTSD. Furthermore, 36.7% of veterans with current war zone PTSD also suffer from major depressive disorder, reported Dr. Marmar, the Lucius N. Littauer Professor of Psychiatry at of the NYU Langone Medical Center.

A total of 1,839 veterans from NVVRS were alive when NVVLS was undertaken, of which 1,450 (78.8%) participated in at least one phase of the latter study. Dr. Marmar and his coinvestigators estimated that 4.5% (95% confidence interval, 1.7%-7.3%) of male and 6.1% (95% CI, 1.8%-10.3%) of female war zone veterans from the Vietnam War currently have PTSD, based on Clinician-Administered PTSD Scale for DSM-5 PTSD criteria. The prevalence of current PTSD from any cause related to service in Vietnam was estimated at 12.2% for males and 8.5% for females, said Dr. Marmar, also director of PTSD research program and chairman of the department of psychiatry at the NYU School of Medicine.

Meanwhile, Dr. Marmar and his associates found that the prevalence of alcohol and other drug abuse was low in both PTSD and subthreshold PTSD.

“Policy implications include the need for greater access to evidence-based mental health services; the importance of integrating mental health treatment into primary care in light of the nearly 20% mortality; attention to the stresses of aging, including retirement, chronic illness, declining social support, and cognitive changes that create difficulties with the management of unwanted memories; and anticipating challenges that lie ahead for Iraq and Afghanistan veterans,” the authors concluded.

The NVVLS was funded by the Department of Veterans Affairs. The authors did not report any financial disclosures.