Dear Editor, Nonadherence, and partial nonadherence to antipsychotic therapy commonly occur among patients with schizophrenia. Moreover, considering that the risk of recurrence and hospitalisation increases as a result of nonadherence, it is imperative to select drugs that strike a balance between clinical efficacy and adverse effects, to ensure a sufficiently high level of drug adherence. One method for assessing drug adherence is using the treatment continuation rate as an index. Ensuring higher levels of treatment retention is vital for improving the treatment outcomes of patients with schizophrenia. Asenapine and brexpiprazole are newer drugs which have most recently been introduced for clinical use in Japan. We reported that brexpiprazole had a significantly higher treatment continuation rate than asenapine. In addition, we retrospectively examined the comparison of treatment retention between asenapine and brexpiprazole in elderly schizophrenia. This was a retrospective cohort study of elderly patients with schizophrenia who were diagnosed with schizophrenia according to the diagnostic criteria provided in the Diagnostic and Statistical Manual of Mental Disorders 5th edition, and were prescribed either asenapine or brexpiprazole. The observation period was from May 2016 (when introduced for clinical use) to 1 January 2018 for asenapine, and April 2018 (when introduced for clinical use) to 1 December 2019 for brexpiprazole. This study was approved by the ethics committee of Fukui Kinen Hospital. Testing of independence was done using Fisher’s exact test. The significance level was P < 0.05. Of 60 patients, 20 (male/female 4/16) received asenapine and 40 (male/female 13/27) received brexpiprazole. There were no significant differences between asenapine and brexpiprazole in mean subject age (64.2 4.2 years; 68.3 7.0 years), and mean duration of illness (31.3 12.3 years; 27.5 16.9 years). The treatment continuation rate results are shown in Figure 1. Brexpiprazole had a significantly higher treatment continuation rate than asenapine (P < 0.05). There was no significant difference in the mean Clinical Global Impressions-Improvement scale (CGI-I) between asenapine and brexpiprazole (3.3 0.9; 3.8 1.1). The reasons for discontinuation of asenapine and brexpiprazole were patient request (6.3% and 5.3%), insufficient efficacy (81.3% and 78.9%), and adverse events (12.4% and 15.8%), respectively. Because the study included all patients treated with either asenapine or brexpiprazole at each institution where data were collected, the number of patients treated with asenapine was smaller than those treated with brexpiprazole. In the present study, no significant differences were observed between the two drugs in terms of CGI-I scores and the main reasons for discontinuation; however, brexpiprazole was found to have a significantly higher treatment continuation rate than asenapine. Brexpiprazole may have included more mildly ill patients than asenapine. On average, women’s psychotic symptoms respond to antipsychotic drugs at doses lower than men’s and are known to have a better prognosis. Therefore, the differences in the proportion of women in each drug group may