Beyond the Bowel: A Narrative Review Examining Bidirectional Mental Health Pathways Across Disorders of Gut-Brain Interaction and Inflammatory Bowel Disease

Irritable bowel syndrome (IBS), functional dyspepsia, and inflammatory bowel disease (IBD) frequently coexist with psychological distress, but their assessment and treatment require distinct clinical interpretations.This narrative review examines how gut-brain evidence can guide psychiatric differentiation, prevent diagnostic overshadowing, and support coordinated care in adults with these conditions.A targeted PubMed/MEDLINE search through August 27, 2026 prioritized consensus reports, systematic reviews, randomized trials, longitudinal studies, and mechanistic reviews.Established neural and neuroendocrine communication is distinguished from proposed symptom-generating mechanisms, which often remain supported predominantly by preclinical evidence.Longitudinal associations between gastrointestinal illness and psychiatric outcomes do not establish individual causation.Assessment distinguishes gastrointestinal-specific fear from psychiatric disorders, screening symptoms from diagnoses, and fear-driven food restriction from eating disorders involving weight or shape concerns.Behavioral therapies and central neuromodulators may improve selected IBS outcomes, although certainty, tolerability, and access vary.Psychological treatment in IBD primarily addresses distress and functioning; inflammatory activity requires separate evaluation.The review proposes a clinical framework linking positive gastrointestinal diagnosis, targeted psychiatric assessment, shared treatment goals, and outcome-specific follow-up.Its contribution is a clinically focused synthesis rather than a validated algorithm or comprehensive systematic review.Incomplete original search documentation and heterogeneous evidence limit reproducibility and generalizability.