Purpose: To estimate the rate of new-onset seizure in ADHD patients in relation to ADHD pharmacotherapy. Methods: A retrospective cohort study of 34,727 patients, ages 6 to 17, with at least two insurance claims bearing ADHD diagnoses during 2003 in the UnitedHealthcare database. Incidence of seizure was calculated for observation time during treatment with atomoxetine and stimulants/bupropion. Results: Seizure incidence among ADHD patients was 4.5/1,000 person-years (p-y; 95% confidence interval 3.7 – 5.5). ADHD patients who received any ADHD medication had an incidence of 3.8/1,000 p-y (3.0 – 4.8) compared to 8.7 (5.8 –12.4) for patients who did not receive any ADHD medication. The relative risk (RR) for current vs non-use of atomoxetine was 1.1 (0.6 – 2.1). For stimulants and bupropion, the RR for current vs non-use was 0.8 (0.6 – 1.3). Elevated seizure risks were found in association with central nervous system (CNS) disease (OR 3.9, 1.2 – 10.9), CNS medications (OR 2.2, 1.3 – 3.6), metabolic disease (OR 2.9, 1.1 – 6.8), and psychiatric disease risk factors (OR 1.7, 1.1 – 2.6). Conclusions: In this study, there was no statistically significant association between use of atomoxetine or stimulants and seizure risk in children ages 6 to 17 years with ADHD and without prior seizure disorder.
