There are many assumptions and generalisations made about ADHD and child sicknesses. While some children suffering from ADHD hardly become sick, others are sick all the time. Child allergies and ADHD cases have been on the increase over the last 20 years, therefore the chances of a child having both conditions is higher than in past generations.
The exact causes of hyperactivity associated with ADHD are unknown. Illnesses such as meningitis, encephalitis as well as foetal alcohol syndrome, affect the central nervous system. In some cases, hyperactivity can be traced back to these illnesses. In most ADHD cases, the children affected have never had such illnesses; most children suffering from meningitis never develop ADHD either.
There is a stronger link to genetics than illness for ADHD. If a child has a parent or close family member with ADHD, then that child stands a far higher chance of having ADHD than a child with no family history of the disorder.
Boys are four to seven times more likely to suffer from ADHD than girls, which further rules out a direct link between childhood illnesses and the disorder.
