Patterns of antidepressant persistence in mood and anxiety disorders: a retrospective population-based cohort study

Controlled studies and practice guidelines encourage antidepressant treatment to be continued for at least 6 to 12 months after symptom remission to reduce the risk of relapses. We aimed to assess the real-world persistence of prescribed antidepressants and identify factors affecting long-term persistence. This retrospective cohort study used outpatient prescription dispensing data from 2015 to 2021. The baseline and follow-up periods were set as 12 months before and after the index date, respectively. Administrative health data for this were obtained from the Population Health Research Data Repository at the Manitoba Centre for Health Policy in Manitoba, Canada. Individuals covered by the Manitoba Health Insurance Registry who initiated an antidepressant prescription and had a diagnosis of mood and anxiety disorders were included. The proportion of individuals who persisted on their first antidepressant prescription was determined at 3, 6, 9, and 12 months, and the odds of persistence were determined using multivariable logistic regression models. Among 76,200 new antidepressant users (63.3% female), 30.2% of individuals filled their first antidepressant prescription only once, and 75.4% of users discontinued within 1 year. The proportion of individuals who persisted with their initial antidepressants declined over 3, 6, 9, and 12 months (56%, 41%, 33%, and 25%, respectively). Adjusted analyses identified several predictors of lower persistence at 12 months, including male sex (vs. female: OR 0.87, 95% CI 0.84–0.90), younger age (< 25 years vs. 25–65 years: OR 0.74, 95% CI 0.71–0.77), receipt of income assistance (vs. no assistance: OR 0.57, 95% CI 0.53–0.61), receiving tricyclic antidepressants (vs. receiving SSRIs: OR 0.31, 95% CI 0.28–0.34), concurrent benzodiazepine use (vs. non-use: OR 0.88, 95% CI 0.84–0.91), prior PTSD diagnosis (vs. no PTSD: OR 0.83, 95% CI 0.76–0.91), and mood and anxiety-related ambulatory visits (vs. no visits: OR 0.92, 95% CI 0.88–0.95). Antidepressant persistence among individuals with mood and anxiety disorders declined over time after the initial prescription and varied by demographic, clinical, and healthcare utilization factors. These findings underscore the need to identify individuals at higher risk of discontinuation and support further research to inform clinical and health system strategies to improve persistence. Not applicable.