Abnormal brain connectivity observed in youth with ADHD, although with small effect size

Key takeaways:

• The ADHD group had higher connectivity in three areas, with peak effect sizes ranging from 0.11 to 0.15.
• These connections were positively associated with reported attention problems.

Researchers identified differences in resting-state subcortico-cortical connectivity between youth with and without ADHD by analyzing almost 10,000 functional brain images, according to data published in The American Journal of Psychiatry.

“We conducted the largest study to date on changes in subcortico-cortical connectivity in ADHD,” Luke J. Norman, PhD, a staff scientist in the office of the clinical director at NIMH, and colleagues wrote. “The brain regions showing altered connectivity align with fronto-striatal models of the disorder, but the effects observed were small.”

To overcome limitations of prior analyses that have had conflicting results, Norman and colleagues used a mega-analytic approach to evaluate resting-state subcortico-cortical connectivity using six neuroimaging datasets. The analysis included neuroimaging data of 1,696 children with ADHD diagnoses (66.39% male; mean age, 10.83 years; standard deviation [SD], 2.17) and 6,737 unaffected children (47.05% male; mean age, 10.33 years; SD, 1.3). Researchers also looked for associations between functional connectivity and ADHD traits in 9,890 children (50.3% male; mean age, 10.77 years; SD, 1.96).

The ADHD group showed higher connectivity in three areas: between the caudate, putamen and nucleus accumbens seeds and the superior temporal gyri/insula/inferior parietal lobe; between the caudate and putamen seeds and the supplementary motor area/precentral gyrus/postcentral gyrus/inferior parietal lobe clusters; and between the amygdala seed and the dorsal anterior cingulate cortex. Researchers noted the peak effect sizes were small (d = 0.11-0.15).

Further, these pathways appeared positively associated with attention problems, again with small peak effect sizes (r = 0.05-0.07).

“The overall pattern of results was robust across two sets of region-of-interest definitions, after adjustments for estimates of general intelligence, and after matching subjects on in-scanner motion,” Norman and colleagues wrote. “Furthermore, this pattern of findings was not shared with commonly, comorbid internalizing or externalizing problems.”

Reference:

• NIH researchers identify brain connections associated with ADHD in youth. https://www.nih.gov/news-events/news-releases/nih-researchers-identify-brain-connections-associated-adhd-youth. Published March 13, 2023. Accessed March 20, 2023.