OBJECTIVES: To compare the economic outcomes of 3 hypothetical cohorts of schizophrenic patients receiving 3 different antipsychotic agents over 6 weeks and 12 months from a public hospital perspective of Hong Kong METHODS: Three hypothetical cohorts of 100 patients were given paliperidone 6mg (PP), olanzapine 10mg (OL) and quetiapine 750mg (QT) for acute exacerbation of schizophrenia. A decision analytic model was used to project the economic outcomes 6 weeks and 12 months after the start of therapy. The categories of inputs required in populating the model were: characteristics of relapse, rates of adverse effects, health care resource utilization, unit costs of health care resources, and switch rate to other oral atypical antipsychotics. Published randomized controlled trial data were used for obtaining response rates of the three drugs. Published data from long-term clinical trials were adopted for rates of discontinuation, switching, relapse and adverse events in the model. Cost of hospitalization, drug costs and other laboratory procedural costs were obtained from the available information of the local health authority. Other unit costs of health care resource data were from published information of the government. Sensitivity analyses were performed on the key parameters to test the robustness of the results. RESULTS: Several conservative approaches were adopted in data analysis. The overall costs of treatment per patient were: US$169(PP), US$235(OL), and US$225(QT) after 6 weeks; and US$5,505(PP), US$5,576(OL), and US$5,809(QT) after 12 months. Sensitivity analyses of the key parameters had no effects on the results. CONCLUSIONS: In the public hospital setting in Hong Kong, estimation using a decision analytic model revealed that the overall cost of treatment using PP for schizophrenic patients with acute exacerbation appears to be less than OL and QT both 6 weeks and 12 months after therapy.