Executive functioning ability in children with ADHD: Effects of subtype and comorbidity

Several current theories of Attention-Deficit/Hyperactivity Disorder (ADHD) propose that a deficit in Executive Functioning (EF) underlies the disorder. EF, which involves such abilities as self-regulation of behavior, planning, and inhibition, is closely associated with the frontal lobes of the brain, and normally develops slowly throughout childhood and adolescence. Although many studies have demonstrated EF impairment in samples of children with ADHD, several important issues remain to be addressed. These include possible differences in EF between DSM-IV-defined subtypes of ADHD, the influence of comorbid conditions, and problems with laboratory measures of EF that make a more ecologically valid measure desirable. The present study examined these issues using a new rating scale of EF, the BRIEF (Behavior Rating Inventory of Executive Function). Children with ADHD, recruited through community support groups and the internet, were found to display deficits in EF, which differed by subtype. EF deficits predicted other outcome measures, including academic and social skills and psychopathology. Finally, the presence of comorbid Oppositional Defiant Disorder was found to make an independent contribution to EF scores even when the severity of ADHD was statistically controlled.