Youth with ADHD: The Impact of Clinical Anxiety on Neuropsychological Functioning

Children with ADHD demonstrate significant deficits in certain executive functions (EFs), including visual and verbal working memory, inhibitory control, cognitive flexibility, and sustained attention. Similar deficits have been observed in children with anxiety, however there is less evidence that inhibitory control is worse in these youth. More recently, research has examined the EF of children with comorbid ADHD and anxiety (ADHD + ANX). There is evidence that suggests that anxiety can play both a protective as well as harmful role for EF in these children. The current study sought to explore whether the performance of children with ADHD + ANX differs from that of children with ADHD alone or anxiety alone on different domains of EF from both a categorical, diagnosis-based perspective as well as a dimensional, symptom severity-based perspective. Further, the role of temperament was examined. A sample of 53 youth (age range 8-16 years) and their parents were recruited through a Developmental and Behavioral Pediatrics practice. They completed measures of anxiety, ADHD, EF (i.e., self-report measures and task-based measures such as inhibitory control, cognitive flexibility, working memory, and attention), and temperament (negative affect, surgency, effortful control). It was hypothesized that children with ADHD + ANX would perform similarly to children with a single diagnosis of ADHD on most measures of EF, but better on tasks of inhibitory control. Further, it was expected that anxiety would moderate the effect of ADHD symptomology on inhibitory control. Analysis of variance tests were used to look at group differences (no diagnosis, anxiety-only, ADHD-only, ADHD + ANX) in EF and temperament. Regression models examined anxiety and ADHD symptoms as predictors of EF. Finally, regression models examined anxiety and temperament (effortful control) as predictors of EF. Analysis of variance tests did not indicate significant group differences in EF. As expected, anxiety did not emerge as a significant moderator of ADHD symptoms in predicting working memory, cognitive flexibility, or globally measured EF. Surprisingly, anxiety did interact with hyperactivity in predicting sustained attention, but not inhibitory control, suggesting that anxiety may actually attenuate impulsivity yielding better task-measured attention abilities. There were no group differences in temperamental effortful control or negative affect, and ADHD + ANX children had similar levels of reported surgency as children with ADHD alone. However, effortful control emerged as a significant moderator of the relation between diagnostic group (anxiety-only and comorbid group) and working memory. Study findings suggest that although some of the results indicate anxiety as a moderator of the relation between ADHD and EF, more research is necessary. The current study lends evidence to the growing research that EF deficits are observed in children with anxiety alone, ADHD alone, and comorbid ADHD and anxiety. Limitations and future directions are discussed