Unpacking ADHD: Part 6 - Peeking Inside the Brain: What Scans Reveal

Peeking Inside the Brain: What Scans Can (and Can't) Tell Us

Brain imaging techniques are like powerful magnifying glasses that help scientists understand ADHD. Structural Magnetic Resonance Imaging (MRI) gives us detailed pictures of the brain's anatomy—its volumes, the thickness of its outer layers, and its surface area (Cortese et al., 2021). This helps us spot physical differences. Functional Magnetic Resonance Imaging (fMRI), on the other hand, shows us brain activity—which parts are lighting up and how different regions are communicating with each other (Cortese et al., 2021). Other techniques, such as Positron Emission Tomography (PET), can look at brain chemicals. However, they are less prominent in recent structural and functional comparisons discussed in the provided research (Dutta et al., 2022).

Brain imaging studies have consistently shown structural differences in children with ADHD, such as smaller volumes in deep brain structures and thinner outer layers in certain areas (Cortese et al., 2021). The recent study by Wu et al. (2024) powerfully used these imaging tools to show how specific brain differences in medicated children normalize (Wu et al., 2024). This research beautifully illustrates that the brain structures of medicated children with milder ADHD symptoms, like the right insula and left nucleus accumbens, look remarkably similar to those of typically developing children. In contrast, unmedicated children with significant ADHD symptoms show clear differences (Wu et al., 2024). While functional imaging tries to reveal differences in brain activity and connectivity patterns, it's important to acknowledge the challenges in achieving consistent findings across broad meta-analyses (Cortese et al., 2021).

Despite these amazing scientific leaps, it's crucial to understand that brain imaging, as it stands today, cannot be used to diagnose ADHD in an individual or to tell a clinician exactly which treatment will work best for a specific person (Cortese et al., 2021; Neuroimaging and ADHD, 2013). Why not? Well, many studies have been small, there might be a bias where only "positive" results get published, different studies sometimes find conflicting things, and the brain differences observed are often very subtle (Cortese et al., 2021). This means there's a big gap between what science learns about ADHD in groups of people and what's useful for a clinician treating an individual patient. While scans can show general patterns of brain differences and the average effects of medication across large groups, the huge variety among people with ADHD, the tiny nature of these differences, and the limits of current imaging technology mean that a single brain scan can't reliably diagnose ADHD or definitively show "better pathways" for your child. This important distinction is key for managing public expectations and for responsible reporting of scientific findings. It reinforces that an ADHD diagnosis is still primarily based on a clinician's clinical evaluation and a person's behavior, not a picture of their brain (Cortese et al., 2021; Neuroimaging and ADHD, 2013).

In Part 7, we'll explore why ADHD is so familiar in society, and why that familiarity often comes with misunderstandings.

HC Telepsych NP

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.