Onno van der Hart

The development and psychometric characteristics of the Somatoform Dissociation Questionnaire (SDQ-20).

According to 19th century French psychiatry and contemporary clinical observations, dissociation pertains to both psychological and somatoform components of experience, reactions, and functions. Because such an instrument was lacking, we aimed to develop a self-reporting questionnaire measuring what we propose to call somatoform dissociation. Patients with dissociative disorder and with other DSM-TV psychiatric diagnoses completed a list of 75 items that, according to clinical experience and expert judgment, could reflect instances of somatoform dissociation. Separate logistic analyses and determination of discriminant indices per item revealed 20 items that best discriminated between those with and without dissociative disorders. Mokken analysis showed that these items are strongly scalable on a dimensional latent scale interpreted to measure somatoform dissociation. Reliability of the scale was high. Construct validity was supported by high intercorrelations with the Dissociation Questionnaire, which measures psychological dissociation, and higher scores of patients with dissociative identity disorder compared with patients with dissociative disorders not otherwise specified. In conclusion, the Somatoform Dissociation Questionnaire (SDQ-20) is a scale of good psychometric quality, which measures somatoform dissociation. The symptoms pertain to negative and positive dissociative phenomena, which were well known in 19th century French psychiatry as the mental stigmata and mental accidents of hysteria.

Degree of Somatoform and Psychological Dissociation in Dissociative Disorder Is Correlated with Reported Trauma

In this study, the prevalence and severity of traumatic experiences as reported by patients with dissociative disorders and with other DSM-IV psychiatric diagnoses were compared. Furthermore, the predictive value of emotional, physical, and sexual trauma with respect to somatoform and psychological dissociation was analyzed. In contrast with comparison patients, dissociative disorder patients reported severe and multifaceted traumatization. Physical and sexual trauma predicted somatoform dissociation, sexual trauma predicted psychological dissociation as well. According to the memories of the dissociative disorder patients, this abuse occurred in an emotionally neglectful and abusive social context. Pathological dissociation was best predicted by early onset of reported intense, chronic and multiple traumatization. Methodological limitations restricting causal inferences between reported trauma and dissociation are discussed.

Trauma-related dissociation: conceptual clarity lost and found

OBJECTIVE Imprecise conceptualizations of dissociation hinder understanding of trauma-related 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 trauma-related 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.

Dissociation in Trauma: A New Definition and Comparison with Previous Formulations

Amid controversy regarding the psychobiological construct of dissociation, efforts to formulate a precise definition of dissociation are rare. Some understandings of dissociation are so broad that a host of common psychobiological phenomena would qualify as dissociative. Overly narrow conceptualizations of dissociation exclude phenomena that originally, and for good reasons, have been regarded as dissociative. A common lack of conceptual distinctions between dissociation as process, organization, deficit, psychological defense, and symptom adds to the current confusion. In previous publications, we criticized many of these perspectives and proposed a detailed psychobiological theory of dissociation in trauma. However, what has remained missing is a precise definition of dissociation in trauma. This article first presents such a definition and elucidates its various components. Next the new definition is compared with several other major definitions of the concept. The strengths of the new formulation are highlighted and discussed.

Guidelines for treating dissociative identity disorder in adults, third revision

Abstract in Undetermined The International Society for the Study of Dissociation (ISSD), the former name of the International Society for the Study of Trauma and Dissociation (ISSTD), adopted the Guidelines for Treating Dissociative Identity Disorder (Multiple Personality Disorder) in Adults in 1994. However, the Guidelines must be responsive to developments in the field and require ongoing review. The first revision of the Guidelines was proposed by the ISSD’s Standards of Practice Committee1 and was adopted by the ISSD Executive Council in 1997 after substantial comment from the ISSD membership. The second revision of the Guidelines was requested and approved in 2005 based on the expertise of a task force of expert clinicians and researchers.2 The current revision was undertaken by a new task force3 in 2009 and 2010 after input from an open-ended survey of the membership. The current revision of the Guidelines focuses specifically on the treatment of dissociative identity disorder (DID) and those forms of disso- ciative disorder not otherwise specified (DDNOS) that are similar to DID. It is intended as a practical guide to the management of adult patients and represents a synthesis of current scientific knowledge and informed clinical practice. There is a separate Guidelines for the Evaluation and Treatment of Dissociative Symptoms in Children and Adolescents (ISSD, 2004) available through the ISSTD and published in the Journal of Trauma & Dissociation. The American Psychiatric Association (2004) has published Practice Guidelines for the Treatment of Patients with Acute Stress Disorder (ASD) and Posttraumatic Stress Disorder (PTSD), which may be relevant to the treatment of DID. (Less)

The development of the somatoform dissociation questionnaire (SDQ-5) as a screening instrument for dissociative disorders.

Using cases of dissociative disorder (n=50) and other DSM‐IV diagnoses (n=50), a somatoform dissociation self‐report questionnaire was developed and its capacity to function as a screening device for dissociative disorders was analysed. A list of 75 items was constructed which, according to clinical experience and expert judgement, could reflect instances of somatoform dissociation. Statistical analyses revealed the 20 best discriminating items. Stepwise forward logistic analysis detected five items which, as a group, provided optimal discrimination between the two groups. At an estimated prevalence rate of dissociative disorders of 10% among psychiatric patients the sensitivity would be 94%, the specificity would be 96%, the positive predictive value would be 72%, and the negative predictive value would be 99%. Cross‐validation in an independent sample (n=33/42) largely corroborated the initial findings. The SDQ‐5 can be used as a brief screening device for dissociative disorders.

Relations among peritraumatic dissociation and posttraumatic stress: A meta-analysis

A meta-analysis was performed on the empirical literature which addressed the relationship of peritraumatic dissociation to posttraumatic stress (PTS). Extensive literature searches were conducted to identify as many relevant studies as possible, and revealed 59 independent eligible studies. All studies were coded using a detailed code sheet that included effect measures, variables that indicated the methodological quality of the studies, and substantial variables that might theoretically affect the relationship between peritraumatic dissociation and PTS. A significant positive relation between peritraumatic dissociation and PTS was found. Differences in the methodological rigor between studies - time elapsed since peritraumatic dissociation, design, sample type, and study type - significantly and sufficiently explained the variability in effect sizes between studies. Theoretical variables did not explain such variability. Although results underline earlier findings, due to designs of the reviewed studies no conclusions could be drawn as to causal relations between peritraumatic dissociation and PTS.

The Dissociation Theory of Pierre Janet

Although the concept of dissociation had been described earlier, Pierre Janet was the first to show clearly and systematically how it is the most direct psychological defence against overwhelming traumatic experiences. He demonstrated that dissociative phenomena play an important role in widely divergent post-traumatic stress responses which he included under the 19th-century diagnosis of hysteria. His dissociation theory is outlined here as a background for Janets specific studies of trauma, it is based on nine concepts developed or elaborated by Janet: psychological automatism, consciousness, subconciousness, narrowed field of consciousness, dissociation, amnesia, suggestibility, fixed idea, and emotion.

Psychometric characteristics of the Somatoform Dissociation Questionnaire: A replication study.

Background: The present study aimed to replicate the results of previous studies concerning the development of two versions of the Somatoform Dissociation Questionnaire. The SDQ-20 evaluates the severity of somatoform dissociative phenomena, and the SDQ-5 is a dissociative disorders screening instrument. Methods: Thirty-one patients with dissociative disorders and 45 consecutive psychiatric outpatients with other DSM-IV diagnoses completed the SDQ-20 and SDQ-5 as well as the Dissociation Questionnaire which measures psychological dissociation. Results: Mokken scale analysis showed that the items of the SDQ-20 are strongly scalable on a latent unidimensional scale. Internal consistency was high. The SDQ-20 convergent validity was supported by high intercorrelations with the DIS-Q. Dissociative patients obtained significantly higher scores than comparison patients. Patients with dissociative identity disorder scored significantly higher compared to patients with dissociative disorder nos. Sensitivity (94%) and specificity (98%) of the SDQ-5 were very satisfactory, as were, at an estimated prevalence rate of dissociative disorders of 10% among psychiatric patients, positive predictive value (84%) and negative predictive value (99%). Conclusions: All results replicated the first findings, and therefore corroborate the conclusion that the SDQ-20 and SDQ-5 are instruments of sound psychometric quality, and that somatoform dissociative phenomena are core symptoms of complex dissociative disorders.

The partus stress reaction: a neglected etiological factor in postpartum psychiatric disorders.

The Partus Stress Reaction: A Neglected Etiological Factor in Postpartum Psychiatric Disorders Nico Moleman;Onno van der Hart;Bessel van der Kolk; The Journal of Nervous and Mental Disease