A taxometric investigation of dissociation in Vietnam veterans

There is long-standing debate about whether elevated dissociative symptoms are common in posttraumatic stress disorder (PTSD) or whether there is a distinct subtype of cases with elevated dissociation. The current investigation examined the latent structure of dissociative symptoms in a sample of 316 male, trauma-exposed Vietnam veterans, 76 of whom were diagnosed with current PTSD. Three taxometric procedures (MAMBAC, MAXEIG, and MAXCOV) were performed on three indicator sets drawn from the Dissociative Experiences Scale. Taxometric analyses consistently revealed a taxon (subtype) of highly dissociative individuals. The taxon members had significantly more severe posttraumatic symptoms and were more often diagnosed with current PTSD than were non-taxon members. Among participants with a current PTSD diagnoses, only 32% belonged to the dissociative taxon, suggesting that there is a subtype of severe PTSD with elevated dissociation.