Unpacking ADHD: Part 2 - ADHD's Unique Footprint on Brain Development

ADHD

When we look closely at the brains of people with ADHD, we see some subtle but widespread differences (National Center for Biotechnology Information, 2020). Big studies using advanced brain imaging, like the Enhancing NeuroImaging Genetics Through Meta-Analysis (ENIGMA) consortium, have shown that children with ADHD often have slightly smaller overall brain volumes, especially in certain deep brain areas like the accumbens, amygdala, caudate, hippocampus, and putamen (Cortese et al., 2021). They also tend to have smaller surface areas in parts of the brain responsible for thinking and processing, particularly in the frontal, cingulate, and temporal regions, and thinner outer layers (cortex) in areas like the fusiform gyrus and temporal pole (Cortese et al., 2021).

Here's the fascinating part: these structural differences are usually most noticeable in childhood. As kids with ADHD grow into teenagers and adults, these specific brain measurements often start to look much more like those of people without ADHD (Cortese et al., 2021). This suggests that ADHD isn't a fixed "defect" but more like a brain that's on a slightly delayed developmental timeline. It's as if their brains are taking a scenic route to maturity, and for many, they eventually catch up or find clever ways to compensate. This fresh perspective changes everything, helping us see ADHD not as a permanent flaw, but as a unique developmental journey, which has big implications for when and how we step in to help.

When scientists look at brain activity (how different parts of the brain "talk" to each other), the picture gets a bit more complicated. While broad studies haven't always found consistent patterns, more focused research on specific brain networks has shown some interesting results. These studies point to challenges in the "default mode," "frontoparietal," and "salience/ventral attention" networks—a kind of "triple network" problem that seems to be at play in ADHD (Cortese et al., 2021).

In our next post, Part 3, we'll zoom in on the specific brain regions most affected by ADHD.

References

American Psychiatric Association. (2025, February 10). ADHD in adults: New research highlights trends and challenges. https://www.psychiatry.org/news-room/apa-blogs/adhd-in-adults-new-research-highlights

Cortese, S., & Castellanos, F. X. (2019). The neurobiology of ADHD: Still an enigma? Frontiers in Human Neuroscience, 13. https://doi.org/10.3389/fnhum.2019.00042

Cortese, S., Solmi, M., & Fusar-Poli, P. (2021). Neuroimaging of attention-deficit/hyperactivity disorder: A narrative review of recent findings. Current Opinion in Psychiatry, 34(2), 108–114. https://doi.org/10.1097/YCO.0000000000000674

Dutta, C. N., Christov-Moore, L., Ombao, H., & Douglas, P. K. (2022). Neuroprotection in late life attention-deficit/hyperactivity disorder: A review of pharmacotherapy and phenotype across the lifespan. Frontiers in Human Neuroscience, 16. https://doi.org/10.3389/fnhum.2022.938501

Kolar, A., & Cortese, S. (2019). The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): What every clinician should know. Current Psychiatry Reports, 21(10), 96. https://doi.org/10.1007/s11920-019-1088-7

National Center for Biotechnology Information. (2020). Attention-Deficit Hyperactivity Disorder. In StatPearls. StatPearls Publishing.

Neuroimaging and ADHD: fMRI, PET, DTI findings, and methodological limitations. (2013). Journal of Attention Disorders, 17(6), 455–469. https://pubmed.ncbi.nlm.nih.gov/23682662/

Visser, J., van der Meer, S., van der Heijden, P. T., & de Jong, J. T. (2024). Unmet needs and priorities for stigma reduction in ADHD: A qualitative study with young adults, parents, teachers, and mental health care professionals. BMC Psychiatry, 24(1), 847. https://doi.org/10.1186/s12888-024-05459-y

Wang, S. Y. A., Manza, P., Tomasi, D., Volkow, N. D., Wang, G. J., & Zhang, Y. (2023). Shared and distinct neurobehavioral phenotypes of child obesity and ADHD. Translational Psychiatry, 13(1), 74. https://doi.org/10.1038/s41398-023-02359-x

Wu, F., Zhang, W., Ji, W., Zhang, Y., Jiang, F., Li, G., Hu, Y., Wei, X., Wang, H., Wang, S. Y. A., Manza, P., Tomasi, D., Volkow, N. D., Gao, X., Wang, G. J., & Zhang, Y. (2024). Stimulant medications in children with ADHD normalize the structure of brain regions associated with attention and reward. Neuropsychopharmacology.