Johan Vanderlinden

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.

The Body Attitude Test for Patients with an Eating Disorder: Psychometric Characteristics of a New Questionnaire

Abstract The Body Attitude Test (BAT) is a new self-report questionnaire developed for female patients suffering from eating disorders. Its psychometric characteristics have been tested in a large number of patients and control subjects (eating disorders, Weight Watchers, and normal subjects). Repeated analyses yielded a stable four factor structure: negative appreciation of body size, lack of familiarity with ones own body, general body dissatisfaction, and a rest factor. Repeated tests in different subgroups have shown the BAT to be reliable and valid, as well as easy and practical (only 20 items).

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.

Animal Defensive Reactions as a Model for Trauma-Induced Dissociative Reactions

Patients with complex dissociative disorders remain in alternating psychophysiological states which are discrete, discontinuous, and resistant against integrative tendencies. In this contribution, a parallel is drawn between animal defensive and recuperative states that are evoked in the face of severe threat and the characteristic responses of dissociative disorder patients as displayed in major dissociative states. Empirical data and clinical observations seem to be supportive of the idea that there are similarities between freezing, concomitant development of analgesia and anesthesia, and acute pain in threatened animals and severely traumatized human beings.

Dissociative experiences and trauma in eating disorders

This study explores the relationship between traumatic experiences and dissociative phenomena in a large group of eating disorder patients (N = 98). Traumatic experiences were assessed by means of a self-report questionnaire and a clinical interview; dissociative experiences were assessed with the newly developed self-reporting Dissociation Questionnaire (DIS-Q). About 25% of the patients reported to have experienced traumatic events in their personal life and this subgroup had significantly higher scores on the DIS-Q, compared with normal control subjects. About 12% of our patient sample mentioned dissociative experiences to a degree as high as in a group of patients with dissociative disorders. Amnesia turned out to be the most specific characteristic in trauma-induced dissociation. These data suggest that trauma-induced dissociative experiences may play an important role in the development of a subgroup of patients with an eating disorder.

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.

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.

Somatoform dissociative symptoms as related to animal defensive reactions to predatory imminence and injury

: The authors hypothesized that there would be a similarity between animal defensive responses to variable predatory imminence and injury and certain somatoform dissociative symptoms of trauma-reporting patients who have dissociative disorder. As a first test of this hypothesis, 12 somatoform symptom clusters consisting of clinically observed somatoform dissociative phenomena were constructed. All clusters discriminated between patients with dissociative disorders (n = 50) and patients with other psychiatric diagnoses (n = 50). Those expressive of the hypothesized similarity--freezing, anesthesia-analgesia, and disturbed eating--belonged to the 5 most characteristic symptoms of dissociative disorder patients. Anesthesia-analgesia, urogenital pain, and freezing symptom clusters independently contributed to predicted presence of dissociative disorder. Using an independent sample, it appeared that anesthesia-analgesia best predicted presence of dissociative disorder after controlling for symptom severity. The results were largely consistent with the hypothesized similarity.

Alexithymia and dermatology: the state of the art.

Background  Alexithymia is a personality trait characterized by difficulties in differentiating and describing feelings. Research indicates that alexithymia acts as a triggering factor for many medical and psychiatric disorders. The interest in alexithymia has increased considerably over the past decade. A state of the art review of recent research on alexithymia in medical and dermatological research is presented.

Somatoform Dissociation Discriminates Among Diagnostic Categories Over and Above General Psychopathology

OBJECTIVE The primary aim of this study was to investigate the hypothesis that somatoform dissociation would differentiate among specific diagnostic categories after controlling for general psychopathology. METHOD The Somatoform Dissociation Questionnaire (SDQ-20), the Dissociative Experiences Scale, and the Symptom Checklist-90-R were completed by patients with DSM-IV diagnoses of dissociative disorders (n = 44), somatoform disorders (n = 47), eating disorders (n = 50), bipolar mood disorder (n = 23), and a group of consecutive psychiatric outpatients with other psychiatric disorders (n = 45), mainly including anxiety disorders, depression, and adjustment disorder. RESULTS The SDQ-20 significantly differentiated among diagnostic groups in the hypothesised order of increasing somatoform dissociation, both before and after statistically controlling for general psychopathology. Somatoform dissociation was extreme in dissociative identity disorder, high in dissociative disorder, not otherwise specified, and increased in somatoform disorders, as well as in a subgroup of patients with eating disorders. In contrast with somatoform dissociation, psychological dissociation did not discriminate between bipolar mood disorder and somatoform disorders. CONCLUSIONS Somatoform dissociation is a unique construct that discriminates among diagnostic categories. It is highly characteristic of dissociative disorder patients, a core feature in many patients with somatoform disorders, and an important symptom cluster in a subgroup of patients with eating disorders.