OBJECTIVE: The goal of this study was to determine the benefits of the continued use of a typical antipsychotic agent following remission from an acute manic episode. METHOD: Immediately following remission of a manic episode treated with the combination of a typical antipsychotic (perphenazine) and a mood stabilizer (lithium, carbamazepine, or valproate), 37 patients were randomly assigned to 6 months of double-blind treatment in which in addition to the mood stabilizer they received either continued perphenazine treatment or placebo. RESULTS: Patients randomly assigned to continue perphenazine treatment, relative to those who discontinued it, were more likely to have a shorter time to depressive relapse, discontinue the study, and have increased rates of dysphoria, depressive symptoms, and extrapyramidal symptoms. CONCLUSIONS: There were no short-term benefits with the continued use of a typical antipsychotic after achieving remission from an episode of acute mania. In fact, its continued use was associated with detrimental effects.