International clinical psychopharmacology vol:10 issue:4 pages:207-13
Risperidone has antiserotonergic and antidopaminergic properties that may make it more effective than conventional antipsychotic agents in the treatment of the negative symptoms of schizophrenia. Clinical trials in chronic schizophrenic patients have shown trends in favor of risperidone in the control of negative symptoms compared with haloperidol, perphenazine or zuclopenthixol, but the differences were not consistently statistically significant. A meta-analysis of the pooled results from six double-blind trials showed that risperidone at doses ranging from 4 to 8 mg/day had a significantly (p < 0.004) higher negative symptom response rate, defined as the percentage of patients with a 20% or more reduction in scores on the negative subscale of the Positive and Negative Syndrome Scale, than patients receiving active controls. The combined patient population treated with 4-8 mg/day of risperidone was 1.43 times more likely to have had a clinical response on the negative symptom subscale than the combined population treated with haloperidol, perphenazine or zuclopenthixol.