Cognitive correlates of attention-deficit hyperactivity disorder in children and adolescents with high intellectual ability

Contains fulltext : 217550.pdf (publisher's version ) (Open Access)Background: There is an ongoing debate as to whether attention-deficit hyperactivity disorder (ADHD) in highly intelligent individuals has a similar presentation as in average intelligent individuals. The aim of this study was to examine the cognitive correlates of ADHD in highly intelligent children and adolescents with ADHD. Method: Two independent samples (N = 204 and N = 84) of (1) high intelligence quotient (IQ) (IQ >= 120) children and adolescents with ADHD were used, carefully matched on age, gender, ADHD severity, and IQ with (2) control participants with high intelligence, (3) participants with ADHD with an average intelligence (IQ 90-110), and (4) control participants with an average intelligence. These samples were selected from the Dutch node of the International Multicenter ADHD Genetics (NeuroIMAGE) and Tracking Adolescents' Individual Lives Survey (TRAILS) cohorts, respectively, in which a large battery of cognitive tasks was administered. Linear mixed models were used to examine the main effects of ADHD and IQ and their interaction on cognitive performance. Results: ADHD-control group differences were not moderated by IQ; mostly equally large ADHD-control differences in cognitive performance were found for high versus average intelligent groups. The small moderating effects found mostly indicated somewhat milder cognitive problems in highly intelligent individuals with ADHD. Overall, highly intelligent children and adolescents with ADHD performed at the level of the average intelligent control children. Conclusions: Our findings indicate the cognitive profile of ADHD is similar in highly versus average intelligent individuals with ADHD, although ADHD-related cognitive deficits may be easily overlooked in the high intelligence population when compared to the typical (i.e., average intelligent) control group.9 p

An evidenced-based perspective on the validity of attention-deficit/hyperactivity disorder in the context of high intelligence

Contains fulltext : 163023.pdf (publisher's version ) (Closed access)The validity of Attention-Deficit/Hyperactivity Disorder (ADHD) in individuals with high intelligence is disputed, since high intelligence may 'mimic' the symptoms of ADHD in the absence of the specific pathophysiological pathways for ADHD. Conversely, increased risk of a missed ADHD diagnosis may occur due to compensatory strategies in the highly intelligent individual. A systematic literature review was performed including cognitive and behavioral studies, addressing a specific set of criteria for validating ADHD in the context of high intelligence. Albeit limited in number, available results suggest that ADHD is a valid construct in the context of high intelligence, showing characteristic clinical features (except possibly for hyperactivity being a less specific pathology marker), course and outcome and a characteristic response to treatment. Importantly, ADHD and IQ are negatively correlated on nearly all phenotypic and cognitive constructs, underlining the need for taking IQ into account as potential moderator in ADHD studies and more systematically studying ADHD in the high intelligent population.27 p