A comparison of two treatment regimens for acute mania: implications for patient recruitment. The current research compares two similar drug treatment protocols, both of which have clinical effects on the core symptoms of mania. To examine these drug effects directly and comparatively for the first time, the authors conducted a parallel trial using a between-subjects design. In the first arm, a daily dose of 300 mg/d of haloperidol was given. In the second arm, a daily dose of 150 mg/d of an equal daily dose of haloperidol, lithium carbonate (12 mmol/d), and phenothiazines was administered, which is the standard protocol for the treatment of acute mania at the Baltimore Psychiatric Research Center. A total of 24 patients participated in the study. Their ages ranged from 18 to 65 years. The sample included nine males and 15 females. Diagnoses were made according to DSM-III-R criteria using the structured clinical interview for DSM disorders. Overall, there were no significant differences between the treatment groups for improvement on the specific mania symptoms. No consistent or strong predictors of response emerged for either treatment. There was a tendency for females to be more responsive to treatment than were males. Furthermore, the authors observed a correlation between plasma levels of haloperidol and improvement in core mania symptoms, although plasma levels of lithium could not be adequately controlled. Overall, the authors suggest that manic patients may experience improvements regardless of whether they are receiving an average daily dose of an antipsychotic, lithium, or a combination of these drugs. They also hypothesize that the therapeutic activity of antipsychotic agents can mask or delay the onset of efficacy of lithium carbonate. Further studies are needed to verify these hypotheses.