Efficacy of risperidone on positive features of schizophrenia.

Dopaminergic hyperactivity mediated via D2 receptors is implicated in the etiology of positive symptoms of schizophrenia, but selective D2 antagonists provide imperfect therapy. This article describes a subanalysis of a trial of risperidone, a combined 5-HT2A/D2 antagonist, in 513 patients with DSM-III-R chronic schizophrenia. Risperidone at 2, 6, 10, and 16 mg/day was compared with placebo and haloperidol 20 mg/day. All doses of risperidone and the 20-mg dose of haloperidol were superior to placebo (mean change from baseline on the PANSS positive and general psychopathology subscales). The 6-mg dose of risperidone also produced significantly more improvement than haloperidol 20 mg. We conclude that risperidone is an effective drug for patients with positive features of schizophrenia.