Low doses of antipsychotic drugs for hospitalized schizophrenia patients in East Asia: 2004 vs. 2001.

We test the hypothesis of increasing prevalence of low-dose antipsychotic use (300 mg/d chlorpromazine-equivalent) in East Asia and examine clinical correlates of conservative dosing. Rates of low-dose antipsychotic prescription were determined for 4535 patients with DSM-IV diagnosis of schizophrenia in six East Asian countries and territories, with comparisons analysed for 2004 vs. 2001. Between 2001 (n=2399 subjects) and 2004 (n=2136 subjects), prescription rates for low doses of antipsychotic drugs (APDs) increased from 24.8% to 44.0% (p<0.001). Low doses were more likely among older patients (p=0.005), during first-lifetime hospitalizations (p<0.001), and among patients with less prominent delusions, hallucinations or disorganized speech (all p<0.05). Multivariate modelling indicated that low doses were strongly associated with older age, first admission, sampling year (2004>2001), less use of antipsychotic polytherapy (all p<0.001) and depot antipsychotics (p=0.009). Conservative dosing of APDs was increasingly prevalent in East Asia. Our findings suggest characteristics of patients who may be particularly likely to require low antipsychotic doses.