Assessment of dissociation symptoms in patients with mental disorders by the Dissociation Questionnaire (DIS-Q).

AIM Dissociative symptoms are often found in psychiatric patients and have been implicated in psychotic trauma. We aimed to explore dissociative tendencies in psychiatric patients including dissociative disorders (DDs), obsessive-compulsive disorder (OCD), eating disorder (ED), and post-traumatic stress disorder (PTSD) by using the Dissociation Questionnaire Japanese version (DIS-Q-J). METHODS We evaluated the reliability and the validity of DIS-Q-J by comparing it with the Dissociative Experience Scale (DES). 107 patients (32 DDs, 28 OCDs, 24 PTSDs, 23 EDs) and 83 controls answered both the DIS-Q-J and the DES questionnaires. In addition, OCD patients were assessed by the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), PTSD patients were assessed by the Impact of Event Scale-Revised (IES-R), and ED patients were assessed by the Bulimic Investigatory Test, Edinburgh (BITE). RESULTS The internal consistency of the total DIS-Q-J and DES scale was high in all groups (Cronbach's alpha coefficients, DIS-Q-J; 0.922-0.975, DES; 0.934-0.957, p<0.01). The correlation between the total scores of the DIS-Q-J and the DES in all groups was significant (Spearman's rank correlation, 0.613-0.777 (p<0.01)). An analysis of variance (ANOVA) showed that the mean total scores of the control and clinical groups were significantly different (p<0.05) for both the DIS-Q-J and DES. CONCLUSION These results suggest that the DIS-Q-J is a useful tool for the assessment of dissociative symptoms.