Early age at seizure onset is a risk factor for attention deficit hyperactivity disorder in children with epilepsy

Attention deficit hyperactivity disorder (ADHD) is one of the most common comorbidities in children with epilepsy but the mechanisms underlying their relationship are not clear. To determine whether an earlier age at seizure onset was associated with ADHD independent of other epilepsy-related factors, data from 203 children with epilepsy (6 to 17 years and 11 months; 53% female) were analyzed. The Diagnostic and Statistical Manual of Mental Disorders fifth edition helped define two groups: epilepsy without (n = 96) or with (n = 107) ADHD. The academic repercussions of ADHD were assessed using a composite school impact index. A binary logistic regression model was fitted considering the effects of age at seizure onset, type of epilepsy, frequency of seizures in the last 12 months, and number of antiseizure medication (ASM) on the ADHD diagnosis and their pairwise interactions. Around half of the children (52%) had a comorbid ADHD. The median school impact index was higher in children with epilepsy with vs without ADHD (33 vs 19%, p < 0.001). The age at seizure onset had a significant effect on ADHD diagnosis (OR = 0.99, 95% Confidence Interval = 0.96-1.01, p = 0.008) independent of other epilepsy-related factors. The risk of ADHD diagnosis decreased by 1% for each additional month of the age at seizure onset. To conclude, the risk of ADHD is higher when seizures begin earlier in life and ADHD exacerbates the adverse impact on school performance, underscoring the imperative for early systematic screening for ADHD from the first seizure.