Regional Volumetric Differences Based on Structural MRI in Children With Two Subtypes of ADHD and Controls

Area of Science:

• Neuroscience
• Developmental Psychology
• Pediatric Neurology

Background:

• Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder.
• ADHD presents with heterogeneous clinical presentations, often categorized into subtypes.
• Understanding the neurobiological underpinnings of ADHD subtypes is crucial for targeted interventions.

Purpose of the Study:

• To compare volumetric magnetic resonance imaging (MRI) measures in specific brain regions between children with ADHD subtypes and controls.
• To investigate the relationship between behavioral ratings of attention and hyperactivity and regional brain volumes.

Main Methods:

• Volumetric MRI scans were acquired from 74 children: 27 controls, 25 with ADHD: Combined type (ADHD:C), and 22 with ADHD: Inattentive type (ADHD:I).
• Region-of-interest analysis focused on the anterior cingulate cortex (ACC) and caudate nucleus.
• Parental behavioral ratings for attention and hyperactivity were collected.

Main Results:

• The ADHD:C group exhibited significantly smaller bilateral volumes of the caudate and ACC compared to controls and the ADHD:I group.
• Parental ratings of attention positively predicted right ACC volume.
• Hyperactivity ratings predicted right caudate volume and, to some extent, right ACC volume.

Conclusions:

• Distinct brain structural differences exist between ADHD subtypes, specifically in the caudate and ACC.
• These findings support the hypothesis that ADHD subtypes may represent biologically distinct phenotypes.
• Neuroimaging findings have implications for understanding the heterogeneity of ADHD.