Characterization of cortical and subcortical abnormalities in drug-naive boys with attention-deficit/hyperactivity disorder

Background: The current study was designed to investigate the anatomical differences in cortical and subcortical morphometry between drug-naive boys with attention-deficit/hyperactivity disorder (ADHD) and healthy controls (HCs) using three-dimensional T1-weighted imaging and to explore the effects of age on morphometric abnormalities. Methods: Fifty-three drug-naive boys with ADHD and 53 HCs underwent high-resolution anatomical magnetic resonance (MR) imaging using a 3-T MR scanner. The FreeSurfer image analysis suite was used to obtain measures of cortical volume, thickness, and surface area, as well as the volumes of 14 subcortical structures. Statistically significant differences in measures between children with ADHD and HCs were evaluated using a least general linear model, with the intracranial volume and age as covariates. Results: Compared to HCs, boys with ADHD exhibited an increased cortical volume in the left frontal eye field (FEF), a decreased surface area in the left ventral frontal cortex (VFC), and a decreased volume in the right putamen (cluster-wise p < 0.05; Monte Carlo-corrected). Moreover, we also observed age-related differences in FEF and VFC between groups. Limitations: The cross-sectional study design limited inferences about the effects of age on regions displaying morphometric differences. Conclusions: To our knowledge, this study is the first to characterize the cortical morphometry, including volume, thickness and surface area, of drug-naive boys with ADHD at the whole brain level; which provided detailed information about neuroanatomical alterations in attention systems beyond effects reported in previous studies at the lobe and sub-lobe levels. Based on our results, boys with ADHD presented significant alterations in cortical and subcortical morphology in several important nodes of the attention network.