Association between previous high-dose antipsychotic therapy and brexpiprazole discontinuation after the initiation of brexpiprazole in patients with schizophrenia or schizoaffective disorder

The objective of this study was to identify the factors associated with brexpiprazole discontinuation after initiating brexpiprazole in patients with schizophrenia or schizoaffective disorder. All patients with schizophrenia or schizoaffective disorder who were started on brexpiprazole in our institution between May 2018 and April 2019 were retrospectively screened. The continuation rate of brexpiprazole during a follow-up period of 16 weeks was examined. Multivariate Cox regression analysis was conducted to identify predictors of brexpiprazole discontinuation. During the follow-up period, 52 out of 120 patients (43.4%) discontinued brexpiprazole. Thirty-three subjects discontinued due to a lack of efficacy, eight more due to intolerability and a further 11 for other reasons. The continuation rate of brexpiprazole among patients who were previously on high-dose antipsychotics (chlorpromazine-equivalent doses > 800 mg) was significantly lower than that in those who were previously on low-dose antipsychotics (chlorpromazine-equivalent doses <= 800 mg). The Cox regression analysis showed that only having been subject to a high dose of their previous antipsychotics was independently associated with an increased risk of brexpiprazole discontinuation (P < 0.001). Patients who were previously on high-dose antipsychotics discontinued brexpiprazole mainly due to inefficacy. Previous high-dose antipsychotic therapy is an independent risk factor for brexpiprazole discontinuation in patients with schizophrenia or schizoaffective disorder.