Persistence of antidepressant treatment in children and adolescents: A population-based cohort study

OBJECTIVE: To determine the prevalence and predictors of persistent antidepressant use among Australian children and adolescents. METHODS: A population-based cohort study was conducted, including children and adolescents aged from 5 to 18 years who initiated an antidepressant between 2014 and 2022, using 10% randoms sample of Pharmaceutical Benefits Scheme (PBS) dispensing data. We measured persistence at 1 and 2 years after initiation, as defined by continuous supply of any antidepressant with no gaps of more than 90 days between dispensings. RESULTS: A total of 44,366 children and adolescents initiated on antidepressants during the study period. Approximately one-quarter (23.1%) received only a single antidepressant dispensing, with a further 33.0% considered persistent users after 1 year and 19.8% considered persistent users after 2 years. Persistence at 1 year was significantly higher in females (adjusted odds ratios (aOR) 1.13 [1.09-1.18]) than males, and in concurrent users of antipsychotics (aOR 1.37 [1.22-1.54]) or psychostimulants (aOR 1.60 [1.49-1.71]) than non-users. The likelihood of persistent antidepressant use at 1 year was lower in individuals with a concession card (aOR 0.81 [0.78-0.85]) than general beneficiaries and in those who initiated with serotonin and norepinephrine reuptake inhibitors (aOR 0.60 [0.54-0.67]) or mirtazapine (aOR 0.45 [0.34-0.51]) compared with selective serotonin reuptake inhibitors. Findings were similar for persistent antidepressant use at 2 years. CONCLUSION: Persistent antidepressant use beyond 1 or 2 years is common among children and adolescents and shows an increasing trend over time. The reasons for and appropriateness of prolonged treatment with antidepressants in this population warrant further investigation.