The systematic review found that ADHD was significantly associated with increased odds of total gastrointestinal symptoms, including constipation, flatulence, encopresis, abdominal pain, dyspepsia, diarrhoea and IBS https://medicalxpress.com/news/2026-09-people-adhd-gut-problems-major.html Meta-Analysis https://journals.sagepub.com/doi/10.1177/10870547261469626