Many patients with severe IBS screen positive for autism and ADHD traits, Swedish study finds.
A Swedish study reports that a substantial proportion of patients with severe IBS screen positive for autism- and ADHD-related traits.
New research from a group of researchers at Linköping University, Karolinska Institutet and the Gillberg Neuropsychiatry Centre at the University of Gothenburg is providing insights into a possible connection between irritable bowel syndrome (IBS) and neurodevelopmental traits associated with autism and attention-deficit/hyperactivity disorder (ADHD).
The study, published in the Scandinavian Journal of Gastroenterology, examined adults receiving specialist care for moderate to severe IBS in Sweden. Researchers recruited 150 patients, with 110 completing screening questionnaires designed to assess autism- and ADHD-related traits. Of those participants, 86 were women.
The findings revealed unexpectedly high rates of positive screening results. Thirty-two percent of participants screened positive for autism-related traits, while 40 percent screened positive for ADHD-related traits. Nearly one in four participants screened positive for both.
These rates are substantially higher than estimates for diagnosed autism and ADHD in the general adult population. However, the researchers emphasised that the questionnaires used in the study were screening tools rather than diagnostic assessments.
Only a small proportion of participants reported having previously received formal diagnoses. About 10 percent reported a prior ADHD diagnosis, while 3.6 percent reported a diagnosis of autism. This suggests that neurodevelopmental traits may be underrecognised in some patients with severe IBS.
The study also found differences in symptom patterns between groups. Participants who screened positive for ADHD-related traits reported significantly higher IBS symptom severity, higher anxiety scores, and more severe gastrointestinal symptoms overall.
Participants who screened positive for autism-related traits showed signs of increased visceral sensitivity. In a rectal balloon barostat examination, they tolerated lower pressure levels before discomfort occurred, suggesting heightened sensitivity to internal bodily sensations.
Across both groups, researchers found a greater overall burden of physical symptoms. Scores measuring somatic symptom severity were significantly higher among participants screening positive for autism or ADHD traits compared with those screening negative for both.
The researchers used a range of validated tools to assess gastrointestinal symptoms, anxiety, depression, pain, and sensory responses. Many participants also underwent barostat testing, which measures how the gut responds to pressure and stretching.
Additional findings suggested that sensory processing patterns may differ between groups. While participants with autism-related traits appeared more pressure-sensitive, those with ADHD-related traits required larger balloon volumes before first perceiving sensations during testing.
The authors say the findings support growing evidence that IBS involves complex interactions between the digestive system and the brain. They suggest that differences in sensory processing, already well documented in autism and ADHD research, may influence how IBS symptoms are experienced. The researchers also noted that some neurodivergent patients may face additional challenges with standard IBS treatments, which often rely on structured routines, dietary adherence, and consistent communication with healthcare providers.
Because the study was cross-sectional, it cannot determine whether neurodevelopmental traits contribute to IBS, whether IBS influences these traits, or whether both are linked through shared biological mechanisms. The authors say larger studies using formal diagnostic evaluations are needed to clarify the relationship.
For now, the findings add to a growing body of research suggesting that understanding IBS may require looking beyond the gut alone and considering how the brain and sensory processing shape the experience of chronic digestive symptoms.
Link to article:
Orell G, Barazanji N, Fernell E, Gillberg C, Lindberg G, Walter S. Traits of autism and attention-deficit/hyperactivity disorder in irritable bowel syndrome with pronounced symptoms. Scand J Gastroenterol. 2026 Apr 23:1-11. doi: 10.1080/00365521.2026.2661968. Online ahead of print. PMID: 42025323
Text by Anna Spyrou, Communications Officer