03/31/2026
If every child with ADHD presents differently, why does the medical community continue to treat the diagnosis as a single category?
ADHD's presentation is notoriously inconsistent. Two children with the same label may have entirely different daily experiences, with one struggling with focus and another with hyperactivity. This variability, or heterogeneity, suggests that a single category is too broad.
Doctors currently rely on the DSM-5, which uses behavioral checklists to make a diagnosis. These lists track symptoms such as inattention, but they rarely reflect the biological processes happening in the brain.
By using normative modeling and morphometric similarity networks, the new study aimed to move beyond behavioral checklists. The research team worked to identify stable biological profiles to see how a child's brain structure deviates from a typical developmental path.
The researchers looked at structural MRI scans from over 1,150 children to create a growth chart for brain connectivity, similar to how a pediatrician tracks height and weight. Instead of looking at one brain region at a time, they mapped “morphometric similarity”—a technique that measures how different brain areas resemble each other in physical traits such as thickness and volume.
The team grouped participants based on how their brain networks deviated from neurotypical scans.
➡️ Biotype 1: showed widespread, global changes in brain networks and was linked to the most severe symptoms. These children also showed a higher likelihood of symptoms persisting as they aged.
➡️ Biotype 2: showed more localized changes, especially in deep brain areas called subcortical regions. These children had moderate symptoms.
➡️ Biotype 3: had minimal changes and cognitive profiles that looked much like those of children without ADHD.
The team validated these types by associating them with genetic risk factors, brain chemicals, and medication responses, confirming that the three groups represented real biological differences.
Different biotypes also responded differently to stimulant medications, supporting the idea that the categories are based on biology instead of only behavior.
Moving toward precision psychiatry changes how ADHD is treated. Instead of examining every diagnosis the same way, doctors can look at the specific biology of a child’s brain, moving ADHD care away from a one-size-fits-all diagnosis. The research suggests that a brain scan could one day help predict which children need the most support.
Longitudinal studies are needed to follow these children as they grow into adults to see if these brain categories remain the same and whether the biotypes stay stable over many years.
