Intellectual disability and ADHD

Abstract

Hyperkinetic disorders (HKS), like attention-deficit/hyperactivity disorder (ADHD), are characterized by the three core symptoms of hyperactivity, inattention, and impulsivity. However, these three symptoms also occur in other mental disorders and in people with intellectual disability. Children with below-average intelligence in particular show substantially higher prevalence rates of these ADHD symptoms, ranging from 8.7% for hyperactivity alone (Emerson, 2003) to 14.8% for any form of ADHD (Dekker & Koot, 2003). Yet only a few specific studies exist on ADHD in children with intellectual disability. Despite some similarities at the symptom level, there are many differences between ADHD and intellectual disability. Nevertheless, a substantial number of studies on psychopharmacotherapy have been conducted in children with intellectual disability with and without additional ADHD symptoms. With certain limitations that must be taken into account in treatment, intellectually disabled children who are hyperkinetic, inattentive, and impulsive also benefit from stimulant therapy. These limitations include that children with intellectual disability respond less well to psychotropic medication on the one hand, while on the other hand they develop adverse effects more quickly and often more severely (Thomson, Maltzeos, Paliokosta & Xenitidis, 2009).