Disorders of Gut-Brain Interaction: Pathophysiology, Diagnosis, and Evidence-Based Management

This chapter provides a comprehensive account of disorders of gut-brain interaction — including irritable bowel syndrome, functional dyspepsia, and functional constipation — viewed through the lens of the Rome IV diagnostic framework. It elucidates the biopsychosocial and neurobiological mechanisms underlying visceral hypersensitivity, altered gut motility, and central sensitisation, and offers a critical appraisal of pharmacological approaches, dietary therapies including the low-FODMAP diet, neuromodulator use, microbiome-targeted interventions, and multidisciplinary psychological treatment modalities.