Risperidone in the treatment of Hispanic inpatients with schizophrenia: a pilot study.

A growing body of scientific evidence over the last two decades suggests that certain ethnic groups may require lower dosages of standard antipsychotics for the treatment of schizophrenia symptoms. Recent studies have implicated the role of genetic and environmental factors in the metabolism of these drugs as the basis for this differential response. In this pilot study, 10 Hispanic and 8 non-Hispanic patients with schizophrenia were enrolled in a double-blind, parallel-group, inpatient risperidone dosing (daily versus twice daily) trial with the novel antipsychotic risperidone. The result of repeated measures ANOVA reveals a significant interaction effect for race, indicative of a faster rate of symptom improvement (PANSS General) in Hispanic patients. The findings suggest that this novel agent may be preferable for certain ethnic groups. A trend toward more frequently occurring extrapyramidal symptoms among Hispanics was also found, which suggests that dosages lower than those typically recommended may be necessary in Hispanic schizophrenics.