Predictors of high-dose antipsychotic prescription in psychiatric patients in Hong Kong.

OBJECTIVE To determine the factors associated with high-dose antipsychotic prescribing for psychiatric patients in Hong Kong. DESIGN Retrospective cross-sectional study. SETTING Psychiatric in-patients and out-patients in the New Territories West Cluster, Hong Kong. PATIENTS A total of 1129 in-patients and 7520 out-patients who received antipsychotic medications on the study date. MAIN OUTCOME MEASURES Demographic and clinical data were compared for patients receiving 'normal' and high dosages of antipsychotic medications. RESULTS High dosages were prescribed for 104 (9.2%) of the in-patients and 137 (1.8%) of out-patients. Antipsychotic polypharmacy was the most powerful predictor of high-dose prescribing, with an odds ratio of 8.88 for in-patients and 10.82 for out-patients. CONCLUSION Antipsychotic polypharmacy was the main determinant of high-dose antipsychotic prescribing in this study. Further studies should be conducted to look for other variables contributing to such prescribing in Hong Kong.