Large study links sensory over-responsivity uniquely to autism and anxiety

When a child winces at the texture of a shirt tag or covers their ears at the hum of a refrigerator, they are experiencing something researchers have long suspected points to deeper patterns in how certain brains are wired. A new analysis of more than 15,000 children has now confirmed what smaller studies hinted at: these strong negative reactions to everyday sensations—what scientists call sensory over-responsivity—appear uniquely tied to autism and anxiety, not to other common neurodevelopmental conditions like ADHD.

Sensory over-responsivity has been part of autism's diagnostic picture for years. The trait shows up in roughly 15 to 20 percent of children overall, but it appears far more often in children with various psychiatric conditions, including anxiety disorders, ADHD, and obsessive-compulsive disorder. The puzzle researchers faced was straightforward but important: when a child has both autism and anxiety, or anxiety and ADHD, which condition is actually driving the sensory sensitivity? Previous studies had mostly looked at one diagnosis at a time, comparing autistic children to controls, or anxious children to controls, without accounting for the fact that these conditions frequently overlap in the same person.

Rebecca Schwarzlose, an assistant professor of psychiatry at Washington University School of Medicine in St. Louis, and her team took a different approach. They combined five separate datasets that had been collected independently over time, some from randomly selected community samples and others enriched with autistic participants. In total, they examined 15,728 children between ages 6 and 18. When they looked at sensory over-responsivity alongside all six psychiatric conditions at once—rather than one at a time—a clearer picture emerged. Sensory over-responsivity remained strongly associated with anxiety symptoms and autism traits. The connections to ADHD and other conditions either shrank to small effect sizes or disappeared entirely.

The strength of this finding lies partly in its scale. Grace Baranek, a professor of occupational science and occupational therapy at the University of Southern California who was not part of the research, noted that merging datasets of this size had not been feasible before. The work aligns with smaller studies published previously and suggests that sensory over-responsivity may have cascading effects on how the nervous system develops. Yet Baranek also flagged a limitation: the study measured sensory sensitivity using a single yes-or-no question to parents asking whether their child seemed overly sensitive to sounds, textures, or smells. That blunt instrument may have missed nuance. Schwarzlose's team has since conducted unpublished work using more precise measures—observing how children actually react to sensory stimuli in a laboratory setting while playing games—and those observations have tracked more closely with parent reports than with children's own accounts, lending confidence to the published results.

The neurobiological picture is still emerging. When the researchers examined brain imaging data from nearly 9,200 of the children using resting-state functional MRI, they found that sensory over-responsivity was linked to reduced connectivity between the cingulo-parietal network, which handles memory, and the caudate nuclei on both sides of the brain, structures that bridge sensory input and behavior. Schwarzlose emphasizes these findings are preliminary; some effect sizes are small and did not replicate clearly in a smaller validation dataset. The team is now conducting more targeted brain imaging studies in which children are exposed to specific sensory stimuli while their brains are scanned, hoping to map the circuits more precisely.

Shulamite Green, an associate professor of developmental psychology at UCLA and a former supervisor of Schwarzlose's, cautioned that the case for ADHD and sensory over-responsivity is not entirely closed. She has observed the two frequently overlap in clinical practice. But the new work suggests something more subtle: the biological mechanisms driving sensory over-responsivity may operate differently in people with anxiety and autism than in those with ADHD. The question of whether sensory differences develop through the same pathways across these groups remains largely unanswered. What is clear is that for those who experience it, sensory over-responsivity can be profoundly disabling. Schwarzlose notes it is nearly universally despised by the people living with it. Understanding what drives this trait—and eventually how to help—remains urgent work in its earliest stages.