New brain study finds it's the severity of autism symptoms, not the diagnosis, that shapes how children's brains are wired

A study published this week in Molecular Psychiatry has found that autism symptom severity, rather than a child's formal diagnosis, corresponds to distinct patterns of brain connectivity and related gene expression. Researchers from the Child Mind Institute studied children diagnosed with either autism spectrum disorder (ASD) or ADHD and found that the biological signature in the brain tracked with the profile of a child's symptoms, not the label on their chart.

The team identified that more severe autism-related symptoms correlated with increased connectivity between two brain networks: the frontoparietal network, which governs executive function and cognitive control, and the default-mode network, which is central to social cognition and self-referential thinking. These are precisely the networks most implicated in autism's social and communication features. Crucially, this pattern appeared across children with both ASD and ADHD diagnoses, suggesting the two conditions share a deeper biological architecture than current diagnostic categories capture.

The practical implication is significant. For decades, children with overlapping ADHD and autistic features have often been caught between two systems: assessed for one condition, missed for the other, and consequently under-supported in school and at home. If what drives brain architecture is symptom profile rather than the label, it changes how clinicians should assess, how schools should accommodate, and how families should advocate. It also opens a research path toward more targeted, biologically-informed interventions rather than one-size-fits-all approaches.