Effect of regulatory warnings on antidepressant prescription rates, use of health services and outcomes among children, adolescents and young adults

Background: Regulatory bodies worldwide, including Health Canada, have issued warnings about prescribing antidepressants to children and adolescents. We sought to determine whether the Health Canada warning had the desired effects on prescribing patterns and outcomes and whether it had any unintended health consequences. Methods: We examined data from prescription and health care databases representing more than 265 000 children, adolescents and young adults annually to determine changes in the rates of antidepressant prescription, use of health services and outcomes in these populations in the 9 years before and the 2 years after the Health Canada warning. We also examined the data for unintended changes in these rates among patients with anxiety disorders. We used young adults as the comparison group because they were not targeted by the warning. Results: Following the warning, the rate of antidepressant prescriptions decreased among children and adolescents (relative risk [RR] 0.86, 95% confidence interval [CI] 0.81-0.91) and among young adults (RR 0.90, 95% CI 0.86-0.93). Ambulatory visits because of depression decreased among children and adolescents (RR 0.90, 95% CI 0.85-0.96) and young adults (RR 0.91, 95% CI 0.87-0.96). The rate of completed suicides among children and adolescents rose significantly after the warning (RR 1.25, 95% CI 1.08-1.44; annual rate per 1000 = 0.04 before and 0.15 after the warning). There was no equivalent change in the rate of completed suicides among young adults (RR 1.01, 95% CI 0.93-1.10; annual rate per 1000 = 0.15 before and 0.22 after the warning). Among patients with an anxiety disorder, the prescription rates did not change among children and adolescents, except for a decrease in the use of selective serotonin reuptake inhibitors other than fluoxetine, but the rates among young adults changed similar to the pattern of changes in the overall prescribing of antidepressants. There was also a significant decrease in the rate of physician visits because of anxiety disorders among young adults after the warning. Interpretation: Health advisories and warnings issued by regulatory bodies may have unintended consequences on the provision of care, delivery of health services and clinical outcomes. Further efforts are required to ensure that health warnings do not result in unexpected harm.