Changes in single symptoms and separate factors of the schizophrenic syndrome after treatment with risperidone or haloperidol

Abstract

Risperidone, a rather selective blocker of D-2 and 5-HT-2 receptors, was, in the doses 1 mg, 4 mg, 8 mg, 12 mg and 16 mg a day, compared to the rather selective D-2 blocker haloperidol in the dose of 10 mg a day, in 88 chronic schizophrenic patients. After one week placebo wash-out, the patients were randomly assigned to one of the six treatment groups and the study was performed as a double blind parallel-group study for 8 weeks. In the present analysis, a special emphasis has been laid on the effects on single symptoms and separate factors in the schizophrenic syndrome. Overall, risperidone in a dose of 4 mg a day was comparable to haloperidol in a dose of 10 mg a day. Risperidone was found to have a curvilinear dose-response curve with an optimum effect of 4 mg day on the negative, anxious/depressive and cognitive factors and with an optimum effect of 8 mg day on the positive and excited factors. While haloperidol had significant effects on the negative and anxious/depressive factors, risperidone had significant effects on all five factors - the positive, the negative, the excited, the anxious/depressive and the cognitive. The fact that the novel drug had significant effects on the cognitive factor might be of great importance as concerns the possibilities for rehabilitation of chronic schizophrenic patients.