Objectives: This study compared treatment persistence between aripiprazole once-monthly (AOM) and paliperidone palmitate 1-month (PP1M) in patients with schizophrenia spectrum disorders using long-term real-world data from a single university hospital. Methods: This retrospective cohort study analyzed electronic medical records of patients treated with long-acting injectable antipsychotics. To reduce structural bias, only patients receiving 1-month formulations, AOM or PP1M, were included. Discontinuation was defined as the absence of an additional injection for more than 60 days after the scheduled date. Kaplan-Meier survival analysis and Cox proportional hazards models were used to evaluate treatment persistence. Results: A total of 308 patients were analyzed (AOM, n=145; PP1M, n=163). The AOM group had a significantly higher proportion of patients without treatment discontinuation than the PP1M group (52.4% vs. 29.5%, p＜0.001). PP1M was associated with a significantly higher hazard of treatment discontinuation than AOM (hazard ratio=1.93, 95% confidence interval=1.40-2.65, p＜0.001). The distribution of discontinuation reasons did not differ significantly between groups (p=0.705). Conclusion AOM was associated with significantly longer treatment persistence than PP1M. These findings suggest that long-acting injectable agent selection may meaningfully influence long-term treatment continuity and should be considered when individualizing maintenance treatment strategies for schizophrenia spectrum disorders.