Comparison of Risperidone and Olanzapine in Bipolar and Schizoaffective Disorders

OBJECTIVE: To compare risperidone and olanzapine for efficacy, tolerability, need for concomitant mood stabilizers, and cost of treatment in bipolar and schizoaffective disorders. METHOD: We conducted a retrospective chart review of 36 consecutive outpatients with DSM-IV bipolar or schizoaffective disorder seen in 3 settings who received risperidone or olanzapine for at least 1 month between May and August 1997. RESULTS: The mean +/- SD doses were 3.7 +/- 3.5 mg/day of risperidone and 12.0 +/- 5.4 mg/day of olanzapine. Between-treatment differences in patient characteristics, psychiatric history, Clinical Global Impressions scale ratings, and duration of treatment were not significant. Similar proportions of patients in the 2 groups reported side effects, including extrapyramidal symptoms, akathisia, tardive dyskinesia, and precipitation of mania by the respective drug. Patients in the olanzapine group received a significantly higher dose of concomitant lithium than those receiving risperidone (mean daily lithium doses: risperidone group, 750 +/- 150 mg; olanzapine group, 1211 +/- 186 mg; p =.006). The total daily acquisition cost per patient was $11.84 for olanzapine versus $5.81 for risperidone. CONCLUSION: Olanzapine and risperidone were equally efficacious and safe in the treatment of patients with bipolar or schizoaffective disorder, but treatment costs and dose of concomitant lithium were lower in risperidone-treated patients.