Prenatal Antidepressant Exposure and the Risk of Attention-deficit/Hyperactivity Disorder in Childhood: A Cohort Study With Triangulation.

BACKGROUND: Uncontrolled confounding from maternal depression and genetic and environmental factors is expected in studies investigating the effect of prenatal antidepressant exposure on the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood and may explain inconsistencies in the existing evidence. We aimed to assess this effect using triangulation. METHODS: Using population-based health registries, we conducted a nationwide cohort study of all children born in Denmark between 1997 and 2017 and followed through 2018 for ADHD. We assessed the effect of prenatal antidepressant exposure on the risk of ADHD in childhood by comparing children with and without prenatal antidepressant exposure in terms of adjusted incidence rate ratios (IRRs), adjusted incidence rate differences (IRDs), and adjusted risk differences (RDs) and the associated 95% confidence intervals (CIs). We triangulated results from four different analytic approaches: an overall analysis, a negative control analysis, a sibling analysis, and a former-user analysis. RESULTS: The overall study cohort consisted of 1,253,362 children, among whom 28,910 (2.3%) had prenatal antidepressant exposure. ADHD during follow-up was diagnosed among 1,411 (4.9%) of the exposed and in 37,196 (3.0%) of the unexposed children. Triangulation suggested an IRR of 1.09-1.15; an IRD less than 1 case/1,000 person-years, and an RD of 0.9%-2.2% over an up to 18-year period. CONCLUSIONS: Based on triangulation, we estimated a modest effect of prenatal antidepressant exposure on the risk of ADHD in childhood. However, considering the limitations of our approaches, this observed association may be partially due to residual biases. See video abstract at, http://links.lww.com/EDE/B935.