Bipolar illness preceded by anorexia nervosa in identical twins.

Concordant bipolar illness in a set of identical twins, preceded in one twin by anorexia nervosa, is described. The literature on monozygotic twins discordant for anorexia nervosa and on the relationship between anorexia nervosa and affective illness is briefly reviewed. It is concluded that familial affective disorders can predispose adolescent females to develop anorexia nervosa.