Executive functioning in hyperactive children as young adults: attention, inhibition, response perseveration, and the impact of comorbidity.

Tests of several executive functions (EFs) as well as direct observations of symptoms of attention deficit hyperactivity disorder (ADHD) during testing were collected at the young adult follow-up (M = 20 years) on a large sample of hyperactive (H; N = 147) and community control (CC; N = 71) children. The EF tasks included tests of attention, inhibition, and response perseveration. The H group was subdivided into those with and without ADHD (+ or w/o) at follow-up. The H+ADHD group made significantly more inhibition errors than the CC group on a Continuous Performance Test (CPT) and showed more ADHD symptoms while performing the CPT. The H+ADHD group also displayed more ADHD symptoms during a letter cancellation task than did both the hyperactive w/o ADHD and CC groups. Both H groups showed slower reaction times during a Card Playing Task. That subset of hyperactive probands with Conduct Disorder (CD) displayed significantly more perseverative responding on that task than did those without CD, but otherwise it did not differ on any other measures. Current level of anxiety contributed adversely to both CPT commission errors and ADHD behavior during the CPT. Comorbid depression did not contribute to any group differences on these tests. Although developmental improvements were found in both the H and the CC groups in their CPT inattention and inhibition scores since adolescence, the H groups remained distinguishable from the CC groups over this period. We conclude that formerly hyperactive children manifest greater EF deficits at follow-up in the areas of inattention, disinhibition, and slowed reaction time and greater ADHD behavior during testing, but these problems are mostly confined to those with current ADHD. Response perseveration, however, was limited to those hyperactive children with CD by follow-up, consistent with Quay's theory of these two disorders.