Response to clozapine in acute mania is more rapid than that of chlorpromazine

The purpose of the present study was to compare the efficacy of clozapine with that of chlorpromazine in an open label manner (both given in association with lithium salts) in the treatment of acute mania. Thirty hospitalized manic patients were entered into the study. All patients met DSM-IV criteria for bipolar disorder, Manic Episode; 27 patients completed the study and three patients dropped for noncompliance. The duration of the study was 3 weeks. Patients were randomly assigned to two treatment groups; group 1 (n = 15) was treated with clozapine at a mean dose of 166 mg/day and group 2 (n = 12) was treated with chlorpromazine at a mean dose of 310 mg/day. Manic symptomatology was rated on Young Rating Scale for Mania (YRSM) each week; side effects were recorded on dosage records and treatment emergent symptoms; extrapyramidal acute side effects were rated on the Simpson-Angus Rating Scale performed at the beginning of the study and after 3 weeks of treatment. A two-way repeated measures analysis of variance on YRMS scores showed a significant time effect (p < 0.0001) and a significant time-group interaction (p < 0.0001). Post-hoc comparison between the two groups showed a significant difference after 2 weeks of treatment (p = 0.0001), with clozapine treated patients showing lower YRSM scores than chlorpromazine treated patients. YRSM scores at the end of the study n;ere not significantly different. Patients treated with clozapine showed a more rapid trend toward amelioration. No clinically relevant side effect was observed during the study.