Risk of ADHD in children with childhood absence epilepsy versus controls: A population-based study.

Introduction: Children with childhood absence epilepsy (CAE) are deemed to be at higher risk of attention deficit hyperactivity disorder (ADHD), however the magnitude of that risk has not been assessed in a population-based study.

Methods: The Rochester Epidemiology Project database was used to identify children with a new diagnosis of CAE while resident in Olmsted County, MN between 1980-2018. For each case, four age- and sex-matched controls without epilepsy were identified. Records of cases and controls screening positive for ADHD were reviewed to confirm this diagnosis. Those with comorbid ADHD and CAE were further assessed to determine if the ADHD diagnosis preceded or followed the epilepsy diagnosis, as well as the impact of ADHD treatment on possible seizure exacerbation and long-term epilepsy course.

Results: Forty-one cases of CAE were identified and matched to 164 controls. ADHD was diagnosed in 17 children (41.5 %) with CAE and 12 controls (7.3 %) (p < 0.001). Compared to those without epilepsy, the diagnosis of ADHD in CAE was more likely to be made by a mental health professional than a primary care provider (p = 0.047). ADHD in CAE typically followed the diagnosis of CAE and in 7/17 cases, was diagnosed after remission of epilepsy and discontinuation of antiseizure medication. There was no difference in the proportion of cases or controls treated with ADHD medication (16/17 cases and 12/12 controls). Both groups had high likelihood of favorable response to ADHD medication and no child with CAE experienced seizure exacerbation with ADHD treatment.

Conclusions: ADHD was 5.7-fold more common in CAE then in children without epilepsy in our population-based study. Treatment with stimulants is highly effective and not associated with worsening of seizures. Primary care providers must be vigilant to carefully screen this population for ADHD.