Switching Patterns of Antidepressant Treatment in Children and Adolescents in Australia, 2014-2022: A Retrospective Population-Based Cohort Study.

BACKGROUND

Antidepressant switching is often indicative of treatment dissatisfaction; however, data regarding patterns, associated factors and timing of switching in children and adolescents remain limited.

OBJECTIVES

This study aimed to determine switching patterns of antidepressant use and predictors of switching in Australian children and adolescents.

METHODS

A retrospective cohort study of children and adolescents aged 5-18 years who initiated antidepressants between 2014 and 2022 was conducted, using a 10% random sample of the national Pharmaceutical Benefits Scheme dispensing data. We determined the proportions of initiators who switched between antidepressants within 12 months of initiation. A Cox proportional hazards model was used to determine the risk of switching by patient characteristic factors, and adjusted hazard ratios (aHR) with 95% confidence intervals (CI) were reported.

RESULTS

We included 44,381 child and adolescent antidepressant initiators, the most commonly initiated antidepressant being fluoxetine. Approximately one in six children and adolescents aged 5-18 years at initiation (15.0%) switched to a different antidepressant within the first 12 months. Most switches were to selective serotonin reuptake inhibitors. Individuals with a commonwealth healthcare concession card were less likely to switch antidepressants within 12 months (aHR 0.91, 95% CI 0.86, 0.96). Females (aHR 1.24, 95% CI 1.17, 1.31), those starting with antidepressants other than fluoxetine and concurrent anxiolytic users were more likely to switch.

CONCLUSIONS

Switching between antidepressants is a common practice among children and adolescents in Australia, with most switches occurring during the early phases of treatment and primarily to selective serotonin reuptake inhibitors. A better understanding of the reasons for switching is important for informing tailored management approaches and improving treatment outcomes.