Traits of autism and attention-deficit/hyperactivity disorder in irritable bowel syndrome with pronounced symptoms

Gastrointestinal symptoms are common in children with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). However, little is known about the relationship between gastrointestinal symptoms with ASD and/or ADHD in adults. Emerging evidence has revealed potential connections between Irritable Bowel Syndrome (IBS) and ASD. Notably, shared genetic architecture has been identified between IBS and ASD. This cross-sectional study aimed at assessing the prevalence of ASD and/or ADHD traits in IBS patients and whether these traits impacted the clinical presentation.

Adult patients with moderate-severe IBS (N = 150) were offered screening questionnaires for ASD and ADHD. The patients also completed questionnaires for symptom severity and underwent a rectal balloon barostat examination. Participants screening positive for ASD and/or ADHD were compared to participants screening negative for both conditions.

Screening questionnaires were obtained from 110 patients (86 women). In total, 34/110 participants screened positive for ASD and 45/110 for ADHD, and 26 among those screened positive for both conditions. IBS symptom severity was higher in the group screening positive for ADHD, and somatic symptom burden was higher in both positive screening groups. Barostat thresholds for maximum tolerable pressure were lower in the group screening positive for ASD, and anxiety scores were higher in the group screening positive for ADHD.

We found that positive screening for ASD and ADHD were both highly prevalent in a cohort of patients with moderate-severe IBS. The patients who screened positive for ASD and/or ADHD presented significant clinical differences compared to those who did not.