Risperidone (R64 766) in psychotic patients. A first clinical therapeutic exploration

Seventeen therapy-resistant adult male psychotic inpatients were treated in an exploratory open study with the new combined serotonin-S2 and dopamine-D2 antagonist risperidone (R 64 766). The mean daily dose was 4.5 mg orally, and the mean duration of treatment 6 months. There were 11 responders, 5 non-responders and 1 drop-out. Risperidone combined an effective antidelusional potency with important contact- and mood-improving properties, while at the same time it reduced existing extrapyramidal symptoms (EPS). Three out of the 5 non-responders were probably underdosed. Risperidone was very well tolerated, reported side effects were mild and transient, and no reason for premature interruption of the therapy.