Pilot clinical investigation of risperidone in the treatment of psychotic patients.

Sixty-one adult psychotic patients were treated for four weeks in an open dose-finding study with the new combined serotonin-dopamine antagonist risperidone (R 64 766). Risperidone had a rapid onset of action; a highly significant decrease in the total score on the Brief Psychiatric Rating Scale (BPRS) was already noticed after the first week of treatment. There was also a significant decrease in score for individual BPRS items related to positive, negative, and affective symptoms. In spite of the withdrawal of antiparkinson medication at selection, a significant decrease in extra-pyramidal symptoms (EPS) was observed, as assessed on the Simpson and Angus Scale. The Clinical Global Impression of therapeutic effect was consistent with the BPRS scores, showing a constant improvement throughout the study. The mean daily dose of risperidone at the end of the study was 3.7 mg. Tolerance was excellent and only mild side-effects were reported. Vital signs, ECG-parameters, and laboratory values remained within normal limits. This study demonstrates that risperidone has great potential as an effective and well-tolerated alternative for the treatment of chronically psychotic patients. It has potent antipsychotic effects, a low EPS-inducing profile, and, at the same time, it improves the negative and affective symptoms of schizophrenia.