Comparative Efficacy of Risperidone and Clozapine in the Treatment of Patients With Refractory Schizophrenia or Schizoaffective Disorder: A Retrospective Analysis

Background: Clozapine is effective in up to 60% of patients with refractory schizophrenia, whereas the efficacy of risperidone remains unknown. This retrospective study examined the relative efficacy of these drugs in chronically institutionalized patients refractory to conventional antipsychotic agents.

Method: A total of 24 patients who at different time periods had received adequate trials of both clozapine and risperidone and met our inclusion criteria for minimum dose and duration of each trial were included; for clozapine, a minimum dose of 300 mg/day had to be maintained for at least 12 weeks, and for risperidone, a minimum dose of 6 mg/day for at least 6 weeks. Information obtained from systematic retrospective chart review was blindly rated by 2 psychiatrists using the 7-point Clinical Global Impressions-Improvement (CGI-I) scale on overall clinical state and along specific symptom domains of positive symptoms, negative symptoms, and aggressive behavior.

Results: The mean ± SD dose was 520 ± 94 mg/day for clozapine and 7.5 ± 2.2 mg/day for risperidone. Fourteen patients (58%) were classified as responders to clozapine, while 6 (25%) responded to risperidone (CGI-I score of 1 or 2); on specific symptom domains, response rates to clozapine were 38% (9/24) on positive symptoms, 29% (7/24) on negative symptoms, and 71% (12/17) on aggressive behavior. For risperidone, response rates were 17% (4/24) on positive symptoms, 8% (2/24) on negative symptoms, and 41% (7/17) on aggressive behavior.

Conclusion: The results of this study support the utility of first giving a risperidone trial in a treatment algorithm for refractory patients because of its better risk/benefit profile compared with clozapine. Clozapine, however, remains our gold standard in the management of these patients.

J Clin Psychiatry 2000;61(7):498-504