Schizophrenia patients discharged on antipsychotic polypharmacy from a public psychiatric hospital in Taiwan, 2006-2021.

The aim of this study was to identify the factors associated with antipsychotic polypharmacy (APP), investigate whether APP could affect the risk of rehospitalization, and explore temporal trends in APP use. Schizophrenia patients discharged from the study hospital between 2006 and 2021 (n = 16,722) were included in the analysis. The logistic regression model was employed to determine the predictors significantly associated with APP use. Survival analysis was used to compare time to rehospitalization between APP and antipsychotic monotherapy (AMT). The temporal trend of APP use was analyzed using the Cochran-Armitage Trend test. In comparison with the patients (n = 10,909) who were discharged on AMT, those (n = 5,813) on APP were significantly more likely to be male gender, to receive LAIs, to take clozapine, to take anticholinergic agents, to have a greater number of previous hospitalizations, and to have a higher CPZ equivalent dose of antipsychotic prescription. The prescription rate of APP significantly increased from 18.4 % in 2006 to 44.9 % in 2021. Compared with AMT, APP was associated with more clozapine use, more LAI use, higher doses of antipsychotics, and an increased risk of rehospitalization. In addition, the prescription of APP continued to increase during the study period.