Background: Increases in prescription drug cost-sharing may decrease adherence to treatment among persons with schizophrenia and lead to discontinuation of use and an increased risk of hospitalization. Objective: The objective of this study was to investigate the impact of new deductible and increased drug copayments implemented on antipsychotic and other drug purchases and on rates of hospitalizations and primary care contacts among persons with schizophrenia in Finland. Research Design: Interrupted time series analysis. Subjects: All persons with schizophrenia in Finland who were alive at the beginning of 2015 (N=41,017). Measures: We measured the rates of antipsychotic, other psychotropic and cardiometabolic drug purchasers, hospitalizations, and primary care contacts during 2015 and 2016 with data collected from several nationwide health care registers. Results: During 2016, the proportion of antipsychotic purchasers decreased by −0.26 percentage points per month [95% confidence interval (CI): −0.47 to −0.05] compared with 2015. The trend of other psychotropic purchasers decreased to −0.13 percentage points per month in 2016 (95% CI: −0.22 to −0.04) compared with 2015 and cardiometabolic drug purchases to −0.17 percentage points per month (95% CI: −0.29 to −0.05) compared with 2015. The decreasing trend of psychiatric hospitalizations in 2015 halted in 2016. There were no other significant differences in health care utilization. Conclusions: In our nationwide time-series analysis, we observed decreases in the slopes of antipsychotic and other drug purchases of persons with schizophrenia after prescription drug cost-sharing increase implementation on January 1, 2016. Policymakers need to be aware of the unintended consequences of increasing cost-sharing among people with severe mental disorders.