[Efficacy and tolerance of risperidone in various doses (report of a study)].

Risperidone was compared in 2 double blind studies with haloperidol and perphenazine in schizophrenic psychoses. According to the maximal daily dose achieved the risperidone group was divided in 4 subgroups and the risperidone efficacy and tolerability in these groups were compared both mutually and in relation to the baseline. With all doses a good global antipsychotic efficacy has been observed. There were no statistically significant differences in influencing of productive or negative symptoms with exception of significantly more pronounced reduction of productive catatonic symptoms with 2 < max < or = 5 mg in comparison with doses higher than 15 mg daily. Extrapyramidal symptoms were less frequent with lower doses: with 2 < max < or = 5 mg significantly lower occurrence of increased muscle tonus and tremor was found than with higher doses. With maximal daily doses above 10 mg antiparkinson drugs had to be applied in more patients and in the case of trihexyphenidyl this difference reached a statistically significant level.