Risperidone: clinical safety and efficacy in schizophrenia.

Risperidone represents a unique pharmacology of potent antagonism of both serotonin and dopamine receptors. In a randomized, parallel-group, double-blind trial of risperidone vs. haloperidol and placebo in 36 schizophrenic patients in acute exacerbation, risperidone showed a quicker onset of antipsychotic activity than did haloperidol. Risperidone treatment was statistically superior to placebo, with a trend toward superiority to haloperidol. Risperidone did not differ from placebo on assessment scales of extrapyramidal side effects, but produced significantly less than did haloperidol. There were no major adverse reactions associated with risperidone use, but it was noted to reduce the signs of tardive dyskinesia. This study suggests that risperidone may offer a superior side-effect profile, and possibly greater efficacy, than a standard neuroleptic such as haloperidol.