ADHD linked to higher rates of gut symptoms

Clinical takeaway: Consider routinely screening patients with ADHD for gastrointestinal symptoms, particularly constipation, IBS, abdominal pain, and fecal incontinence, as these comorbidities may be common and affect quality of life.

Growing interest in the gut-brain axis has highlighted links between neurodevelopmental conditions and gastrointestinal health. While GI symptoms are well recognized in autism, their prevalence in ADHD has been less clear, potentially leaving an important source of patient burden underrecognized.

A systematic review and meta-analysis published in the Journal of Attention Disorders pooled data from 23 studies involving more than 1.9 million participants from multiple countries to assess the relationship between ADHD and gastrointestinal symptoms. Overall, individuals with ADHD were about 48% more likely to report GI symptoms than those without ADHD.

The strongest associations were seen for functional bowel symptoms. ADHD was linked to nearly double the odds of constipation, a 58% increase in irritable bowel syndrome (IBS), and more than fourfold higher odds of encopresis. The analysis also found higher rates of dyspepsia (52% increase), abdominal pain (88% increase), diarrhea (more than doubled), and nonspecific stomach or bowel complaints (82% increase).

The authors noted that the findings do not establish causality. Possible explanations include ADHD-related behaviors such as irregular eating patterns and impulsivity, medication-related GI adverse effects, gut microbiome differences, and altered gut-brain signaling. Most included studies did not stratify patients by ADHD medication use, leaving uncertainty about the relative contributions of the disorder itself versus treatment effects.

"We can't yet say ADHD causes these gut problems, or exactly what is driving the link, but the pattern is striking enough to warrant attention," said senior author Dr. Saran Shantikumar. "Clinicians caring for people with ADHD may want to consider asking about gastrointestinal symptoms, particularly if they may be affecting quality of life."

Source: Blake S, et al. (2026 Sep 10) J Atten Disord. The Association Between Attention-Deficit Hyperactivity Disorder and Gastrointestinal Symptoms: A Systematic Review and Meta-Analysis