Structural Alterations in Cortical Thickness and Volume in Attention Deficit Hyperactivity Disorder (ADHD): An Exploratory Surface-Based Morphometric Study

PURPOSE: This study aims to investigate the significant clusters of structural alterations across cortical regions associated with attention deficit hyperactivity disorder (ADHD) and explore their potential functional implications. METHODS: A cross-sectional, exploratory surface-based morphometric analysis of cortical thickness and volume in the left and right hemispheres was conducted using FreeSurfer (Martinos Center for Biomedical Imaging) on a publicly available structural magnetic resonance imaging (MRI) dataset. The final analytic sample consisted of 34 observations, including 11 participants with ADHD and 23 participants without ADHD (controls). Participants spanned a range of ages, and group comparisons were performed between ADHD and control participants. Age was included as a continuous covariate in the statistical model to account for developmental variability. Surface-based morphometric data were analyzed with a minimum z-score threshold of 1.3, with cluster-wise correction (cluster-wise p-value (CWP) ≤ 0.05) applied to account for multiple comparisons. Clusters showing significant differences were mapped to anatomical regions, and their functional relevance was interpreted. RESULTS: Reduced cortical thickness was observed in the right superior frontal gyrus and increased in the left postcentral gyrus. Both hemispheres demonstrated multiple clusters showing significant (CWP ≤ 0.0002) increases or decreases in volume. Increased volume was observed in the right precentral, postcentral, lingual, and fusiform gyri, as well as the left postcentral gyrus, lateral occipital gyrus, inferior parietal cortex, and rostral middle frontal cortex. A decreased volume was observed in the right superior frontal and left supramarginal gyri. Bidirectional volume changes were also noted in the right lateral occipital gyrus and rostral middle frontal cortex. CONCLUSION: These findings suggest that ADHD is associated with region-specific alterations in cortical thickness and volume, particularly within executive, motor, and sensory processing regions. Given the mixed-age ADHD cohort and exploratory design, these results should be interpreted as hypothesis-generating, warranting validation in larger, age-stratified cohorts.