ADHD severity is associated with white matter microstructure in the subgenual cingulum

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Clinical Psychology

Background:

• Attention Deficit Hyperactivity Disorder (ADHD) is a complex neurodevelopmental disorder.
• Understanding the neurobiological underpinnings of ADHD, including white matter alterations, is crucial.
• Investigating co-occurring autistic traits in ADHD can provide a more comprehensive phenotype.

Purpose of the Study:

• To examine associations between white matter (WM) microstructure and clinical variability in adolescents with ADHD.
• To explore the relationship between WM microstructure and ADHD severity in the subgenual cingulum.
• To assess WM microstructure's link to autistic traits in the right corticospinal tract using a tract-specific approach.

Main Methods:

• Diffusion MRI scans were acquired from 40 male adolescents (19 with ADHD, 21 controls).
• Validated questionnaires assessed clinical ADHD and autism variation.
• Deterministic tractography using spherical deconvolution mapped the subgenual cingulum and corticospinal tract.

Main Results:

• Positive correlation between fractional anisotropy and ADHD severity in the left subgenual cingulum.
• Negative correlation between radial diffusivity and ADHD severity in the left subgenual cingulum.
• Positive correlation between fractional anisotropy and autistic traits in the right corticospinal tract's inferior segment.

Conclusions:

• Findings suggest anatomical correlates for ADHD severity and autistic symptoms in specific WM tracts.
• Tract-specific approaches may reveal associations missed by voxelwise methods.
• This approach offers improved sensitivity for detecting microstructural variations linked to phenotypic variability.