Tandem hypnosis with identical bulimic twins: case report.

Hypnosis has been used in the treatment of bulimia nervosa from the early 1980s. Dissociation theory identified a certain subgroup of eating disordered patients with dissociative signs and symptoms. These patients react well to hypnotherapy. Simultaneous hypnosis ("tandem hypnosis") in the treatment of two female 19-year-old monozygotic twins led to a very successful outcome after 6 sessions. During the therapy, attempts were made to work through the physical abuse the subjects suffered from their father. Hypnobehavioural methods were used and treatment was combined with five individual sessions. In the cases presented here, the subjects' traumatic history, their high hypnotic susceptibility, and the effectiveness of hypnotherapy seem to support the dissociative mechanism of symptom development. A systemic approach involving the integration of family therapeutical and hypnotherapeutical interventions proved to be useful. The role of these types of hypnotherapy interventions is still undervalued.