Pre-war vulnerability is just as important as combat-related trauma in predicting whether veterans' symptoms of post-traumatic stress disorder (PTSD) will be long-lasting, according to new research published in Clinical Psychological Science, a journal of the Association for Psychological Science.
Researcher Bruce Dohrenwend and colleagues at Columbia's Mailman School of Public Health and the New York State Psychiatric Institute found that traumatic experiences during combat predicted the onset of the full complement of symptoms, known as the PTSD "syndrome," in Vietnam veterans. But other factors - such as pre-war psychological vulnerabilities - were equally important for predicting whether the syndrome persisted.
The researchers re-examined data from a subsample of 260 male veterans from the National Vietnam Veterans Readjustment Study. All of the veterans in the subsample had received diagnostic examinations by experienced clinicians that included information about the onset of the disorder and whether it was still current 11 to 12 years after the war ended.
Dohrenwend and colleagues focused on the roles of three primary factors: severity of combat exposure (e.g., life-threatening experiences or traumatic events during combat), pre-war vulnerabilities (e.g., childhood physical abuse, family history of substance abuse), and involvement in harming civilians or prisoners.
The data indicated that stressful combat exposure was necessary for the onset of the PTSD syndrome, as 98% of the veterans who developed the PTSD syndrome had experienced one or more traumatic events.
But combat exposure alone was not sufficient to cause the PTSD syndrome.
Of the soldiers who experienced any potentially traumatic combat exposures, only 31.6% developed the PTSD syndrome. When the researchers limited their analysis to the soldiers who experienced the most severe traumatic exposures, there was still a substantial proportion - about 30% - that did not develop the syndrome. This suggests that there were other factors and vulnerabilities involved for the minority of exposed who did end up developing the PTSD syndrome.