At least 20% of children with epilepsy have clinical attention-deficit hyperactivity disorder (ADHD) compared to 3% to 7% of the general pediatric population. Several mechanisms may account for the high prevalence, such as a common genetic propensity, noradrenergic system dysregulation, subclinical epileptiform discharges, or even seizures, antiepileptic drug effects, and psychosocial factors. At the same time, children with attention-deficit hyperactivity disorder have a higher than normal rate of electroencephalography abnormalities (5.6-30.1% vs. 3.5%). Methylphenidate treatment is equally efficient in children with isolated attention-deficit hyperactivity disorder and in children with attention-deficit hyperactivity disorder and epilepsy (70%-77%). Electroencephalography screening in patients with attention-deficit hyperactivity disorder in the absence of other clinical indications or before starting methylphenidate treatment is not currently indicated. Methylphenidate is considered safe for use in children who are seizure-free. However, the few reports of seizure aggravation in methylphenidate-treated children with uncontrolled epilepsy have raised concern.

Epilepsy and attention-deficit hyperactivity disorder (ADHD) were reported to co-occur at rates higher than expected for coincidental findings. This study investigated the prevalence of both disorders in community-based primary care practice. The central database of the second-largest health maintenance organization in Israel was searched for all children aged 6 to 13 years (n = 284 419; 51.5% males) diagnosed as having ADHD according to the physicians' records and/or the filling of at least 10 prescriptions for antiepileptic medications according to pharmacy records. The prevalence of epilepsy in the total population was 5 out of 1000 children, and the prevalence of ADHD was 12.6%. More than one-fourth (27.7%) of the epileptic children were also diagnosed as having ADHD. On multivariate analysis, children with ADHD had almost twice the risk of epilepsy than children without ADHD. This study supports hospital-based findings of a strong interrelationship between ADHD and epilepsy. The high rate of ADHD in Israeli children warrants further investigation.

Children with BECTS have an impaired ability to process verbal information. The deficiency is apparently a result of the pathological electrical discharges that are part of the syndrome and are not dependent on the epileptic focus laterality, the number of seizures, or the anti-epileptic treatment.