Patients' attitudes toward medication have been shown to be a predictor of nonadherence to antipsychotic treatment. However, most previous studies that explored this relationship used a cross-sectional design. It is important to explore the association of attitudes toward drugs with discontinuation at different time points during antipsychotic treatment. In this study, we investigated the association of attitudes toward drugs (measured by the Drug Attitude Inventory (DAI-10)) with adherence at seven time points (baseline, 4 weeks, 8 weeks, 12 weeks, 26 weeks, 39 weeks, and 52 weeks) during 1 year of treatment. Factors that were potentially associated with attitudes toward drugs at the time point of interest were also studied.Demographic characteristics, psychopathology, social functioning, and attitudes toward drugs (measured by the DAI-10) were collected at baseline, 4 weeks, 8 weeks, 12 weeks, 26 weeks, 39 weeks and 52 weeks. The association of attitudes toward drugs (measured by DAI-10) with adherence at the seven time points was calculated using the Mann‒Whitney U test. The optimal cutoff point for the DAI-10 was then determined using receiver operating characteristic (ROC) analysis. Cox regression analysis was conducted to further investigate the association of DAI-10 scores with discontinuation, controlling for potential confounding variables. We used multiple regression analysis to identify the factors associated with DAI-10 scores.Among the six time points, only baseline DAI-10 total scores were significantly different between the completed and discontinued groups (p = 0.004). Female sex and a baseline DAI-10 total score greater than - 1 were found to be independent protective factors against discontinuation of antipsychotic drug treatments during the 1-year follow-up. At baseline, the severity of the disease (CGI-s) and insight regarding the disease were shown to be associated with DAI-10 total scores.Attitudes toward antipsychotic drugs at baseline were shown to play a crucial role in predicting treatment discontinuation.The data were collected from a clinical trial and the clinical trials.gov ID of the study is NCT01057849.© 2023. The Author(s).