Components of Intelligence and Attention in Boys with ADHD

In the present study we compared the performance of boys with ADHD with the norms from the general population. We measured the performance of 85 boys with newly diagnosed ADHD aged 6 to 13 in the Working Memory Index and the Processing Speed Index of the German version of the Wechsler Intelligence Scale for Children (WISC-IV) as well as the performance of 68 of those children (aged 6 to 10) in the Test of Attentional Performance for Children (KITAP). Additionally to the comparison between the results of the complete sample with the standardization data we conducted analyses for children with the Combined and the Primarily Hyperactive subtypes and children with the Primarily Inattentive subtype separately. The children showed deficits in working memory, stability of reaction time, inhibition, cognitive flexibility, sustained attention and divided attention with effect sizes lying in the moderate to large range. Differences to the norm in processing speed were shown only in the group of children with the Primarily Inattentive subtype. In all investigated parameters a maximum of 50% of children showed performance below average.