Recent Developments in the Neurobiology of Dissociation

There is a growing recognition by researchers and clinicians that dissociative states are an integral component of traumatic stress response. The term dissociation has been employed to describe a spectrum of subjective experiences in which perceptual, affective, memory, and identity functions are altered. Particular symptoms or syndromes associated with dissociative states include distorted sensory perceptions, altered time perception, amnesia, derealization, depersonalization, conversion symptoms, fugue states, and multiple personality (Freud & Breuer, 1953; Mayer-Gross, 1935; Hilgard, 1977; Spiegel & Cardena 1991; Bremner et al., 1992). Despite the broad array of symptoms associated with dissociative states in post-traumatic stress disorder (PTSD), some recent data suggest that these symptoms may be expressed across individuals as a single symptom cluster, rather than as independent clusters of symptoms (Bremner et al., in review).