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% (p0.001). Low doses were more likely among older patients (p=0.005), during first-lifetime hospitalizations (p0.001), and among patients with less prominent delusions, hallucinations or disorganized speech (all p0.05). Multivariate modelling indicated that low doses were strongly associated with older age, first admission, sampling year (20042001), less use of antipsychotic polytherapy (all p0.001) 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.