Abstracts

Rationale: To describe rates of maternal ADHD in children with co-morbid ADHD and epilepsy (ADHD/E) and to compare severity of ADHD symptoms in these mothers with (FAM+) and without (FAM-) additional first or second-degree relative(s) with epilepsy. Methods: Mothers of children enrolled in a randomized controlled trial of extended release methylphenidate in children with ADHD/E were invited to participate in this study. Mothers with epilepsy and/or of probands who have mental retardation or symptomatic epilepsy were excluded. Twenty-two mothers were eligible to participate, of whom sixteen mothers enrolled. These mothers were assessed by structured interview for current or past ADHD diagnoses using the ADHD module of the KSADS and current ADHD symptom severity using the ADHD Rating Scale IV (ADHD RS). Results: Fifty percent of the mothers studied had current or past ADHD; 37.5% had both. Four of five (80%) FAM+ mothers had ADHD vs. 4/11 (36%) FAM- mothers (p=0.14). FAM+ mothers had more current hyperactivity symptoms (mean 5.4+0.9SD) than FAM- mothers (1.4+2.2, t=-3.781, p=0.01), as well as higher current ADHD severity (ADHD RS total score 25.2+14.4 vs. 10.0+8.3; t=-2.738, p=0.02) and ADHD RS hyperactivity scores (11.4+7.6 vs. 5.6+7.5; t=-3.065, p<0.01). Conclusions: The observed rate of ADHD diagnoses in mothers of children with co-morbid ADHD and epilepsy is elevated compared to the rate of approximately 18% for mothers of children with ADHD without epilepsy reported in the literature. Hyperactivity symptoms and ADHD severity are further elevated among mothers who have additional close family members with epilepsy. Rates of ADHD are known to be elevated about 10 fold in children with epilepsy compared to the general child population. ADHD in a child with epilepsy can be related to many factors associated with the epilepsy itself, including abnormal electrical activity, the effect of seizures on the brain, adverse effects of antiepileptic drugs (AEDs), and/or brain abnormalities that underlie the epilepsy, including inherited abnormalities. The present study sought to disentangle shared familial risk from the effects of ongoing abnormal electrical activity and the effects of AEDs by studying rates of ADHD in mothers of children with ADHD/E. The findings of this study suggest that ADHD symptoms in children with epilepsy and their mothers reflect shared familial genetic or environmental risk. These factors may lead to ADHD in some family members and co-morbid ADHD and epilepsy in others. A larger, well-controlled study of these relationships is warranted.