Abstract
The patient described is a 33-year-old woman, L., who developed a transient dual personality while undergoing desensitization for contact phobia, the alternate personality, Toni, manifesting overtly aggressive behaviour. L. was taught how to behave angrily using role-playing techniques within 48 hours of Toni's first appearance and the alternate personality did not reappear after this treatment was commenced. It is suggested that behavioural psychotherapy may, in some instances of multiple personality, have advantages over psychodynamically oriented psychotherapy, which has frequently been advocated as the treatment of choice for this condition.