Dissociative disorders among inpatients with drug or alcohol dependency.

Objective: To determine the prevalence of dissociative disorders among inpatients with alcohol or drug dependency.

Method: The Dissociative Experiences Scale was used to screen 215 consecutive inpatients admitted to the dependency treatment center of a large mental hospital over a 1-year period (March 1, 2003, to March 31, 2004). Patients who had scores of 30.0 or above were compared with patients who scored below 10.0 on the scale. The patients in both groups were then evaluated using the Dissociative Disorders Interview Schedule and the Structured Clinical Interview for DSM-IV Dissociative Disorders. The interviewers were blind to the Dissociative Experiences Scale scores.

Results: Of the patients, 36.7% had a Dissociative Experiences Scale score of 30.0 or above. The prevalence of DSM-IV dissociative disorders was 17.2% (N = 37). On average, 64.9% of these patients' dissociative experiences had started 3.6 years (SD = 2.9; range, 1.0-11.0 years) before onset of the substance use. Patients with dissociative disorders were younger, and the mean duration of their remission periods was shorter. Dissociative disorder patients tended to use more than 1 substance, and drugs were used more frequently than alcohol in this group. The frequency of borderline personality disorder, somatization disorder, history of suicide attempt, and childhood abuse and neglect occurred more frequently in the dissociative disorder group than in the nondissociative disorder group. History of suicide attempt (p = .005), female sex (p = .050), and childhood emotional abuse (p = .010) were significant predictors of a dissociative disorder diagnosis. Significantly more patients with dissociative disorders stopped their treatment prematurely (p < .001).

Conclusion: Impact of dissociative disorders on development and treatment of substance dependency requires further study.