A dose-outcome analysis of risperidone

Although the establishment of appropriate dosage ranges for antipsychotics has important ramifications for both short-term treatment and long-term therapeutic outcomes, difficulties in dosing persist. Evidence exists that initial dosing recommendations for the titration of risperidone to 6 mg/day in 3 days are excessive. This study examines dosage trends of risperidone and further examines the relationship between dose and outcome by determination of discharge rates among individuals receiving varying doses of the drug.

Records of individuals receiving risperidone in Maryland state psychiatric facilities from March 1994 through February 1997 (N = 1056) were examined. Discharge rates and time to discharge were measured by Kaplan-Meier survival curve analysis.

As risperidone use has risen each year since its introduction, mean doses in both inpatients and discharged patients have steadily declined. Additionally, risperidone doses for discharged patients were significantly lower than those for patients remaining in the hospital. Furthermore, patients receiving 2 and 4 mg/day were significantly more likely to be discharged than those receiving 6 mg/day (log-rank chi2 = 13.54, df = 2, p = .0011). This difference was seen in patients with similar diagnoses, ages, and racial status.

Patients treated with doses less than the 6-mg/day initial dosing recommendations have better outcomes in terms of discharge. This finding should encourage clinicians to utilize adequate trials of risperidone aimed at stabilizing patients on doses in the 2- to 4-mg/day range before proceeding to higher doses.