Bulimia nervosa in a pair of male monozygotic twins.

This is a report of a pair of male monozygotic twins meeting the DSM-III-R criteria for bulimia nervosa. At the age of 15, both brothers began to diet and suffered from bulimia. They were admitted to psychiatric hospitals and separated. After admission, their clinical course dramatically changed. The differences in their clinical courses and endocrinological data are suggestive as to the roles of environmental and hereditary factors in the etiology of bulimia nervosa.