Neuropsychological correlates of childhood attention-deficit/hyperactivity disorder: Explainable by comorbid disruptive behavior or reading problems?

Abstract

Questions remain as to whether neuropsychological processing deficits associated with child attention-deficit/hyperactivity disorder (ADHD) are accounted for by co-occurring disorders, especially in clinical samples. The authors examined ADHD and comorbid oppositional defiant, conduct, and reading disorders. Boys with ADHD displayed hypothesized deficits on effortful neuropsychological tasks regardless of categorical or dimensional control of comorbid antisocial behavior problems. The same result held when reading problems were controlled, although boys with ADHD plus reading disorder (n = 16) exhibited specific impairment on linguistic output tasks. Simultaneous control of reading and behavior problems yielded the same result. Overall, results suggest that in a clinical sample, difficulties on effortful neuropsychological tasks that require planning or controlled motor output pertain at least in part to ADHD and are not fully accounted for by comorbid conditions.

Executive Functions in Preschool Children with Aggressive Behavior: Impairments in Inhibitory Control

“…In their review, Pennington and Ozonoff (1996) concluded that impairments in EF found in children with DBD were due to the presence of comorbid ADHD. Since then, this finding has been confirmed in several other studies (e.g., Clark et al 2000;Nigg et al 1998;Oosterlaan et al 2005). However, in several other studies, the relation between aggression and EF impairments was maintained while controlling for ADHD (Déry et al 1999;Séguin et al 1999Séguin et al , 2004.…”

Testing Hypotheses Regarding the Causes of Comorbidity: Examining the Underlying Deficits of Comorbid Disorders.

“…The model parameters for Simulation 2 were identical to Simulation 1 except that the underlying deficit score was not perfectly correlated with the symptom score. Again, we chose correlations between the underlying deficit score and the symptom score that approximated those found for ADHD and underlying deficits associated with ADHD (e.g., executive functioning; Nigg, Hinshaw, Carte, & Treuting, 1998) and for RD and underlying deficits associated with RD (e.g., phonological processes; Willcutt et al, 2001). The simulated correlations between the underlying deficit score and the symptom score approximated .35 for Disorder A (ADHD) and .60 for Disorder B (RD).…”

The influence of working memory load on response inhibition in children with attention-deficit/hyperactivity disorder or reading disorder

“…Research on ADHD that has not taken into account the effect of RD, may have mistakenly attributed the deficit to ADHD (Lazar & Frank, 1998;Nigg, Hinshaw, Carte, & Treuting, 1998;Wu et al, 2002). Therefore, it will be important to control for this comorbidity when trying to find out which deficits are a unique feature of ADHD (Banaschewski et al, 2005;Lazar & Frank, 1998;Sergeant et al, 2002).…”