Adolescent weight loss during treatment with olanzapine.

Antipsychotic medications are increasingly used in adolescents for a variety of psychiatric difficulties, including psychosis, bipolar disorder, and aggression. Weight gain is a significant side effect of neuroleptics, which may limit adolescents' compliance with these medications. This report presents a case of significant weight loss while on olanzapine, with a body mass index (BMI) falling from 25 to 19.5 during 8 months of treatment. Possible mechanisms for this effect are discussed.