Onno van der Hart

The role of dissociation in (complex) posttraumatic stress disorder (PTSD) has been insufficiently recognized for at least two reasons: the view that dissociation is a peripheral, not a central feature of PTSD, and existing confusion regarding the nature of dissociation. In this conceptual article, the authors address both issues by postulating that traumatization essentially involves some degree of division or dissociation of psychobiological systems that constitute personality. One or more dissociative parts of the personality avoid traumatic memories and perform functions in daily life, while one or more other parts remain fixated in traumatic experiences and defensive actions. Dissociative parts manifest in negative and positive dissociative symptoms that should be distinguished from alterations of consciousness. Complex PTSD involves a more complex structural dissociation than simple PTSD.

This study examined the quality of self-reported memories of traumatic experiences in participants with dissociative identity disorder (DID) and compared them with their memories of non-traumatic, but emotionally significant life experiences. Systematic interview data were gathered from 30 DID patients in The Netherlands. All participants reported a history of severe childhood abuse; 93.3% reported some period of amnesia for the index traumatic event, and 33.3% reported periods of amnesia for significant non-traumatic childhood experiences. All participants who had been amnestic for their trauma reported that their memories were initially retrieved in the form of somatosensory flashbacks. This suggests that, like PTSD patients, DID patients at least initially recall their trauma not as a narrative, but as somatosensory re-experiencing. Surprisingly, however, DID participants also recalled emotionally charged non-traumatic life events with significant somatosensory components, a phenomenon that ha...

Objective: Imprecise conceptualizations of dissociation hinder understanding of traumarelated dissociation. An heuristic resolution for research and clinical practice is proposed. Method: Current conceptualizations of dissociation are critically examined. They are compared with a new theory that incorporates classical views on dissociation with other contemporary theories related to traumatization, viewing dissociation as a lack of integration among psychobiological systems that constitute personality, that is, as a structural dissociation of the personality. Results: Most current views of dissociation are overinclusive and underinclusive. They embrace non-dissociative phenomena – rigid alterations in the level and field of consciousness – prevalent in non-traumatized populations, and which do not require structural dissociation. These views also largely disregard somatoform and positive symptoms of dissociation and underestimate integrative deficiencies, while emphasizing the psychological defensive function of dissociation. They do not offer a common psychobiological pathway for the spectrum of trauma-related disorders. Structural dissociation of the personality likely involves divisions among at least two psychobiological systems, each including a more or less distinct apperceptive centre, that is, a dissociative part of the personality. Three prototypical levels of structural dissociation are postulated to correlate with particular traumarelated disorders. Conclusions: Limitation of the concept of dissociation to structural dividedness of the personality sets it apart from related but non-dissociative phenomena and provides a taxonomy of dissociative symptoms. It postulates a common psychobiological pathway for all trauma-related disorders. Trauma-related dissociation is maintained by integrative deficits and phobic avoidance. This conceptualization advances diagnosis, classification, treatment and research of trauma-related disorders.