Clinical predictors of acute risperidone response in schizophrenia, schizoaffective disorder, and psychotic mood disorders

In studies of patients with schizophrenia, the atypical antipsychotic risperidone has been shown to be comparable in efficacy to haloperidol and, at dosages of 4 to 8 mg/day, to have a lower rate of extrapyramidal side effects. However, little is known about the efficacy of risperidone in patients with schizophrenia refractory to treatment with typical antipsychotics, schizoaffective disorder, and psychotic mood disorders. The purpose of this study was to assess the efficacy of risperidone in the treatment of these disorders and to identify clinical factors associated with risperidone response.

By surveying treating clinicians and chart data, we assessed response to risperidone and factors associated with response to risperidone in 144 consecutive patients treated with the drug for at least 2 weeks at a regional state psychiatric hospital.

Patients displaying a moderate-to-marked response to risperidone were more likely to be younger; receive diagnoses of bipolar disorder or schizoaffective disorder, depressive type; and have a shorter duration of illness and shorter length of stay prior to risperidone treatment. Response to risperidone was sufficient to allow discharge in 26% of patients with treatment-refractory schizophrenia hospitalized for at least 10 weeks prior to risperidone and in 11% of patients with treatment-refractory schizophrenia hospitalized for greater than 1 year.

Risperidone may be a useful alternative or adjunctive treatment for patients with schizophrenia refractory to treatment with standard antipsychotic agents, schizoaffective disorder (especially the depressive type), and bipolar disorder when used in conjunction with mood stabilizers.