Olanzapine Versus Risperidone in the Treatment of Manic or Mixed States in Bipolar I Disorder: A Randomized, Double-Blind Trial

Objective: To compare olanzapine and risperidone in the treatment of nonpsychotic acute manic or mixed episodes.

Method: This 3-week, randomized, controlled, double-blind, parallel multicenter study compared olanzapine (5-20 mg/day; N = 165) and risperidone (1-6 mg/day; N = 164) among hospital inpatients who met DSM-IV criteria for bipolar I disorder, manic or mixed episode, without psychotic features. The study was conducted at 30 sites in the United States between July 2001 and June 2002. The primary outcome measure was the mean change in the Young Mania Rating Scale (YMRS) total score. Secondary measures included the 21-item Hamilton Rating Scale for Depression (HAM-D-21), the Montgomery-Asberg Depression Rating Scale (MADRS), the Clinical Global Impressions-Bipolar Version (CGI-BP) severity of illness scale, and the Cognitive Test for Delirium (CTD). Quality of life (Short Form Health Survey [SF-12]), psychological well-being (Psychological General Well-Being [PGWB] inventory), and sexual functioning were also compared.

Results: Mean modal doses for olanzapine and risperidone were 14.7 mg/day and 3.9 mg/day, respectively. Between treatments, there was no difference in mean change in the YMRS, MADRS, CTD, PGWB, or SF-12 measures or in remission or response rates. Significantly more olanzapine-treated patients completed the study compared with risperidone patients (78.7% vs. 67.0%; p = .019). Olanzapine-treated patients had greater HAM-D-21 (p = .040) and CGI-BP (p = .026) score improvement across the study. Olanzapine-treated patients experienced greater elevations in liver function enzymes (p < .05) and increase in weight (2.5 kg vs. 1.6 kg; p = .004), while risperidone-treated patients were more likely to experience prolactin elevation (51.73 ng/mL vs. 8.23 ng/mL; p < .001) and sexual dysfunction (total score increase of 1.75 vs. 0.64; p = .049).

Conclusion: Both olanzapine and risperidone treatment yielded similar improvements in mania. The olanzapine group had significantly greater improvements in secondary measures of severity and depressive symptoms and better study completion rates but experienced more weight gain.