Antimalarial psychosis revisited.

Drug-induced psychosis resulted from the administration of quinacrine hydrochloride at a dosage of 100 mg twice daily for the treatment of discoid lupus. After two weeks of drug treatment, the patient exhibited symptoms similar to those seen in the manic phase of bipolar affective disorder. Although the incidence of antimalarial psychosis is unclear and perhaps small, we recommend close observation of patients for behavioral changes suggesting the development of antimalarial psychosis. Astute observation, leading to the early detection of behavioral changes, may help avert the development of a costly and disabling complication of drug therapy.