Group treatment for complex dissociative disorders: a randomized clinical trial

BACKGROUND: Patients with complex dissociative disorders (CDD) report high levels of childhood- abuse experiences, clinical comorbidity, functional impairment, and treatment utilization. Although a few naturalistic studies indicate that these patients can benefit from psychotherapy, no randomized controlled trials have been reported with this patient-group. The current study evaluates a structured protocolled group treatment delivered in a naturalistic clinical setting to patients with CDD, as an add-on to individual treatment. METHODS: Fifty nine patients with CDD were randomized to 20 sessions of stabilizing group–treatment, conjoint with individual therapy, or individual therapy alone, in a delayed-treatment design. The treatment was based on the manual Coping with Trauma-Related Dissociation. The primary outcome was Global Assessment of Functioning (GAF), while secondary outcomes were PTSD and dissociative symptoms, general psychopathology, and interpersonal difficulties. RESULTS: Mixed effect models showed no condition x time interaction during the delayed treatment period, indicating no immediate differences between conditions in the primary outcome. Similar results were observed for secondary outcomes. Within-group effects were non-significant in both conditions from baseline to end of treatment, but significant improvements in psychosocial function, PTSD symptoms, and general psychopathology were observed over a 6-months follow-up period. CONCLUSION: In the first randomized controlled trial for the treatment of complex dissociative disorders, stabilizing group treatment did not produce immediate superior outcomes. Treatment was shown to be associated with improvements in psychological functioning. TRIAL REGISTRATION: Clinical Trials (NCT02450617). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-022-03970-8.