Somatoform dissociation discriminates among diagnostic categories over andabove 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 Dissocation Questionnaire (SDQ-20), the Dissociative Experiences Scale, and the Symptom Checklist-90-R were completed by patien ts with DSM-IV diagnoses of dissociative disorders (n = 44), somatoform dis orders (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 adj ustment 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 dissoc iative disorder, not otherwise specified, and increased in somatoform disor ders, as well as in a subgroup of patients with eating disorders. In contra st with somatoform dissociation, psychological dissociation did not discrim inate between bipolar mood disorder and somatoform disorders. Conclusions: Somatoform dissociation is a unique construct that discriminat es among diagnostic categories. It is highly characteristic of dissociative disorder patients, a core feature in many patients with somatoform disorde rs, and an important symptom cluster in a subgroup of patients with eating disorders.