Posttraumatic stress disorder, dissociation, and trauma exposure in depressed and nondepressed veterans.

Increasing evidence indicates that exposure to traumatic events predisposes individuals to depressive symptoms as well as to emotional and psychophysiological symptoms covered under the diagnostic criteria of posttraumatic stress disorder (PTSD). Trauma exposure history and PTSD symptoms would, therefore, be expected to be more common in a depressed population than in a nondepressed group. To examine the association between trauma exposure (trauma load), dissociation, and depression, we administered clinical interviews and an assessment package derived from existing instruments (including the Dissociative Experiences Scale; DES) to 101 veteran patients with histories of clinically significant depression and a comparison group of 49 medical patients with no history of depression. The depression group had experienced significantly higher numbers of traumatic incidents, had higher average DES scores, and more frequently met diagnostic criteria for PTSD. The findings support the argument for a causal or predisposing effect of trauma in the expression of clinically significant depression.