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Prewar vulnerabilities may contribute to PTSD as much as combat

The long-term persistence of posttraumatic stress disorder symptoms in combat veterans depends as much on prewar vulnerabilities as it does combat-related trauma, according to recent study results.

Bruce Dohrenwend, PhD, of Columbia’s Mailman School of Public Health, and colleagues found that traumatic experiences during combat alone predicted the onset of all symptoms related to the disorder, but other factors — including prewar vulnerabilities such as physical abuse during childhood and family history of substance use — were just as important in determining how long those symptoms would last.

The researchers examined data on 260 male veterans who were enrolled in the National Vietnam Veterans Readjustment Study. They focused on three factors: the severity of the veterans’ combat exposure, pre-war vulnerabilities and direct or indirect involvement in harming civilians and prisoners. PTSD symptoms were evaluated 11 to 12 years after the war.

Results indicated that only combat exposure was necessary for the onset of PTSD symptom syndrome (PSS) — defined as the co-occurrence of Criteria B, C and D for at least 1 month; 98% of veterans who developed PSS experienced one or more traumatic events.

Of the veterans who experienced Criterion A stressors during the Vietnam War, 31.6% developed PSS. Approximately 30% of the veterans reporting the highest number of life-threatening experiences still did not have onsets of PSS (RR=9.55; 95% CI, 2.49-36.63), suggesting that there were other factors in the development of the syndrome. The most significant of these factors included childhood experience of physical abuse and childhood conduct disorder (39%).

Age also significantly contributed to PSS onset. For example, men who entered the Vietnam War aged 25 years or younger were almost seven times as likely (25.8%) to have PSS onset vs. men aged 25 years or older (3.7%). Additionally, veterans who were personally involved in harming prisoners and veterans who were personally involved in harming civilians had onsets of PSS at a rate of 76.1% and 53.9%, respectively.

Dohrenwend and colleagues also found that 49.5% of the veterans who did not develop war-related PSS as a result of experiencing Criterion A stressors went on to develop one or more other Axis 1 disorders, including alcoholism, which was the most prevalent at 32.1%.

The estimated onset of PSS among veterans high on all three factors examined in the study — combat exposure, prewar vulnerabilities and direct or indirect involvement in harming civilians and prisoners — reached 97%.

“Our results have implications for policy that need attention,” the researchers wrote. “If the goal is to reduce rates of highly chronic war-related PTSD, as we believe it must be, then the positive interaction of severity of combat exposure and vulnerability with current PSS points to the need to keep the more vulnerable soldiers out of the most severe combat situations. Though this may seem obvious, it was not the US policy in Vietnam ...”

Disclosure: The researchers report no relevant financial disclosures.