Trauma Types as Differential Predictors of Posttraumatic Stress Disorder (PTSD), Major Depressive Disorder (MDD), and Their Comorbidity

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are 2 of the most common mental health conditions subsequent to traumatic exposure among military personnel, and these disorders are frequently comorbid. This comorbidity is associated with substantial personal and societal costs. Identification of military personnel at higher risk for developing comorbid PTSD/MDD is important, yet limited research has examined potential correlates of this comorbidity. The present study examined whether specific types of traumatic events increase the likelihood of comorbid PTSD/MDD as compared with MDD or PTSD alone among a sample of 7,047 Canadian Forces personnel (5,012 men, 2,035 women) who had experienced a traumatic event. A complex pattern of findings emerged such that trauma types were differentially associated with diagnostic status, and the pattern of associations was different among men relative to women. Nonsexual interpersonal trauma had the broadest and most consistent relationship with diagnostic status in both sexes, undisclosed/other trauma was associated with PTSD/MDD in both sexes, and accident or unexpected trauma and traumas occurring as a refugee or civilian in a war zone were not associated with diagnostic outcome for either sex. Deployment-related trauma was uniquely associated with PTSD-only among men and PTSD/MDD among women. Although sexual trauma was associated with PTSD-only, MDD-only, and PTSD/MDD among women, it was not associated with mental health disorders among men. These findings indicate that trauma type may facilitate identification of military personnel at increased likelihood for PTSD/MDD comorbidity and its associated greater morbidity and mortality.