Volume of discrete brain structures in complex dissociative disorders: preliminary findings.

Based on findings in traumatized animals and patients with posttraumatic stress disorder, and on traumatogenic models of complex dissociative disorders, it was hypothesized that (1) patients with complex dissociative disorders have smaller volumes of hippocampus, parahippocampal gyrus, and amygdala than normal controls, (2) these volumes are associated with severity of psychoform and somatoform dissociative symptoms, and (3) patients who recovered from dissociative identity disorder (DID) have more hippocampal volume that patients with florid DID. The preliminary findings of the study are supportive of these hypotheses. Psychotherapy for dissociative disorders may affect hippocampal volume, but longitudinal studies are required to document this potential causal relationship.