Effect of regulatory warnings on antidepressant prescribing for children and adolescents.

OBJECTIVE: To evaluate the effect of UK and US warnings placed in response to reports of suicidal thinking in pediatric patients receiving selective serotonin reuptake inhibitor and selective norepinephrine reuptake inhibitor antidepressants on antidepressant prescribing for children and adolescents.
DESIGN: Interrupted time-series analysis of antidepressant prescriptions.
SETTING: Tennessee's Medicaid program, January 1, 2002, through September 30, 2005. PARTICIPANTS: A mean of 405,000 children and adolescents aged 2 to 17 years qualified each month. Main Exposure Piecewise linear regression models were used to estimate the cumulative effect of the warnings, which were considered the exposure of interest. MAIN OUTCOME MEASURES: Monthly proportions of study children and adolescents who were new users of antidepressants, had discontinuity in antidepressant use, or were users of other psychotropic drugs.
RESULTS: During the 2 years preceding the UK warning, there was no trend in the monthly proportions of new antidepressant users, with 23 new users per 10 000 persons per month. This proportion subsequently decreased 33% (95% confidence interval, 23% to 41%; P < .001) by 21 months following the UK warning. The reduction was most pronounced for the nonfluoxetine selective serotonin reuptake inhibitors and selective norepinephrine reuptake inhibitors, where initiations decreased 54% (95% confidence interval, 46% to 62%; P < .001). In contrast, new users of fluoxetine increased 60% (95% confidence interval, 9% to 135%; P = .02). There was no increase in discontinuations of antidepressants, and there was no evidence of substitution of other psychotropic drugs.
CONCLUSION: The regulatory warnings led to decreased use of antidepressants in children and adolescents, but the clinical and public health consequences of this change are unknown.