Even though an estimated 750,000 children are living with epilepsy in the USA, a far more common type of seizure is a febrile seizure, a convulsion caused by a fever. In fact, 2% to 5% of children will have a febrile seizure at some point in childhood, but previous research has shown no long-term problems from these seizures. Now, however, a new study suggests that there is some overlap between children who have either kind of seizure and children eventually diagnosed with ADHD.
Between 1990 and 2007, all of the children born in Denmark were entered into a study designed to examine the link between childhood epilepsy, febrile seizures or convulsions, and ADHD. This study included more than 900,000 children, just over 21,000 of whom developed ADHD.
The most commonly observed seizure type were febrile seizures, which occurred to just over 35,000 children in the study. Of these, a little more than 1,100 developed ADHD, or approximately 3% of them. Just under 14,500 children were diagnosed with epilepsy, and about 6% of them developed ADHD. Overall, nearly 8% of the children who had both febrile seizures and epilepsy went on to develop ADHD, making kids with epilepsy about twice as likely as children with febrile seizures to have ADHD. Kids with febrile seizures and epilepsy both are almost three times as likely to develop ADHD than if they had no seizures.
The study took into account socioeconomic factors, risk factors during birth and family history. More male children than female children developed ADHD — though this could result from bias in identification of the condition– yet female children with epilepsy were more likely than males to develop ADHD. Febrile seizures, meanwhile, led to about equal risk of ADHD among boys and girls.
Knowing that seizures and epilepsy can make ADHD more common may help doctors and parents in screening children, which then allows for earlier intervention and better treatment. But the study findings do not mean seizures cause ADHD. It shows that children predisposed to ADHD may also be predisposed to seizures.
More study will need to be done to see if it’s possible to decrease risks of ADHD for children with epilepsy. There also needs to be more study on if the type of seizures or epilepsy syndrome or response to treatment impacts rates of ADHD.