Characterizing Behavior, Sex, and Subtype in Childhood ADHD via the Related Spectrum of Functional Network Connectivity at Rest

This study examines sex differences between children with and without ADHD. Specifically, functional near-infrared spectroscopy (fNIRS) resting-state functional connectivity measures were used to analyze neural profiles of female and male children based on both group and symptom severity score. Participants, aged 6-8, participated in this study by performing a Passive Viewing Paradigm resting-state task. The K-SADS interview was used to determine ADHD diagnosis and subtype, from which a continuous symptom severity score across group and subtype was calculated. It was found that female children with combined-type ADHD demonstrate different neural profiles than male children overall and based on symptom severity. Male children with ADHD, across subtypes, demonstrate less refined functional connectivity. Males with the combined type also show less significant connectivity. Most notably, within the combined-type group, connectivity increases as symptom severity increases in male children whereas connectivity decreases as symptom severity increases in female children, contrasting from their typically developing peers.