Behavioral and neurofunctional profiles of delay aversion in children with attention-deficit hyperactivity disorder

Despite substantial efforts to unravel cognitive heterogeneity in ADHD, the examination of motivational variability, particularly delay aversion, remains limited. This study aimed to identify homogeneous delay-averse profiles in children with ADHD to understand motivational deficits. Delay-averse profiles were examined in a clinically well-characterized sample of 43 children with ADHD and 47 control participants using cluster analyses on an experiential delay discounting task. External validation analyses included parents' and teachers' clinical ratings, and fNIRS-based resting-state functional connectivity (rsFC) from the frontoparietal (FPN) and the default mode (DMN) networks. A five-profile solution best fit the data. Two clusters, labeled Conventional and Conventional-steeper, exhibited a conventional reward discount with increased delay but differed in the discounting slope. Three clusters demonstrated altered discounting: Steep discounting (abrupt devaluation of the reward), Shallow discounting (shallow discounting), and Zero discounting (no devaluation across delay durations). 77.78% of ADHD-C children clustered into steep discounting profiles, while 41.67% of ADHD-IN children were found in Shallow and Zero profiles, showing a significant disparity in the distribution of categorical presentations. External validation showed no differences in clinical ratings. However, clusters showing Zero and Shallow discounting demonstrated hypoconnectivity within and between FPN and DMN nodes. Delay aversion in ADHD spans a continuum from decreased to increased discounting rather than being solely defined by steeper discounting. These findings highlight the relevance of dimensional approaches in capturing ADHD's motivational heterogeneity and identifying distinct neurobiological substrates, with implications for improving diagnostic protocols and intervention strategies through the incorporation of behavioral measures of reward processing.