Abstract
We compared 34 preschool boys with attention deficit hyperactivity disorder (ADHD) to 30 community comparison boys without behavioral problems on a battery of neuropsychological and academic achievement tests along with behavioral observations. The battery of 25 measures was reduced to 4 dimensions through dimensional (factor) analysis. Comparison of the 2 groups revealed that boys with ADHD performed more poorly than comparison boys on 2 of the 4 dimensions, these being motor control and working memory‐persistence. No differences were found on the dimensions of verbal learning‐memory or picture identification‐factual knowledge. The results suggest that achievement problems are evident early in development in clinic‐referred children with ADHD and may be related to deficiencies in more fundamental neuropsychological functions. These early deficits in motor control and working memory seem to be an inherent part of ADHD, supporting both the neuromaturational nature of the disorder and current efforts to more broadly conceptualize it as involving deficits in executive functions beyond the core problems in behavioral inhibition and sustained attention.