Behavioral and brain functional characteristics of children with Attention-Deficit/Hyperactivity disorder and anxiety trait.

The current study aimed to explore the behavioral, daily-life executive functional, and brain functional connectivity patterns in children with attention-deficit/hyperactivity disorder (ADHD) and anxiety. A total of 246 children with non-comorbid ADHD and 91 healthy controls (HCs) participated in the current study, among whom 175 subjects went through resting-state functional magnetic resonance imaging (fMRI) scans. The ADHD participants were divided into two subgroups: ADHD with a high level of anxiety (ADHD + ANX) and ADHD with a low level of anxiety (ADHD-ANX). The Child Behavior Checklist (CBCL) and the Behavior Rating Inventory of Executive Function (BRIEF) were used to capture the behavioral and daily-life executive functional characteristics. Independent component analysis with dual regression models was applied to the fMRI data. All statistical models were estimated with age and sex as covariates. Compared with the ADHD-ANX group, the ADHD + ANX group showed more withdrawn, somatic, social, thought, attention, delinquent, and aggressive problems (all corrected p < 0.05). The ADHD + ANX group also displayed more impaired emotional control and working memory than the ADHD-ANX (all corrected p < 0.05). The ADHD-ANX group, but not the ADHD + ANX group, showed elevated functional connectivity within the default mode network compared with the HC group. The mean function connectivity within the default mode network significantly mediated the correlation between anxiety level and attention problems. In sum, anxiety in children with ADHD was associated with more social, emotional, and behavioral problems, more impaired daily-life executive function, and altered brain function. Our work provides important information on the heterogeneity of ADHD.