OBJECTIVES: With the widespread of second-generation antipsychotics (SGAs) used among children and adolescents, the treatment effectiveness has been of great interest alongside with the efficacy and safety in this population. The study was designed to assess whether SGAs are associated with reduced service uses and service costs in the real world. Factors associated with health service costs were also examined. METHODS: The claim data (PIMC) of 1996-2008 from the National Insurance Plan of Taiwan was used. Patients aged less than 20 with an incident use of antipsychotics and last for over 12 months during this period were included for analysis. Comparisons were made between 8 SGAs and 2 first-generation antipsychotics (FGAs). Changes in service uses and service costs (all-cause, psychiatric service, non-psychiatric service costs, and medication costs) were compared. Mann-Whitney U tests and 95% confidence interval were used to examine differences. Multivariate regressions with propensity scores adjustment were performed to explore factors associated with psychiatric service costs. RESULTS: A total of 343 encounters were included and results showed reduced psychiatric service uses in SGAs group, but not psychiatric services costs in the SGAs group. Antipsychotics costs were nearly 6-fold higher in the SGAs group, but the antiparkinsonian medication costs were not statistically different between two groups. Factor positively associated with service costs included excess filler (RR=7.9, p<0.0002), relapse event (RR=4.0, p<0.0001) and adverse event like EPS (RR=1.6, p<0.008), while types of antipsychotics and diagnoses were not significant factors after adjusting for covariates. CONCLUSIONS: SGAs were associated with reduced psychiatric service uses as compared to FGAs within the 12-month treatment period; however, service costs were not different and medication costs were significantly higher in the SGAs group. Excess fillers, relapse and incidence of EPS were factors of high costs among children and adolescents psychiatric patients treated with antipsychotics in Taiwan.