Stress, Anxiety and depression can affect all parts of the body, including the gut. The nervous system triggers a release of chemicals and hormones that create a “fight or flight” response – which is designed to make you alert, ready to face the threat or run to safety. Mental stress is often a major underlying cause behind bowel problems such as diarrhoea, constipation and bloating. However, it’s also a risk factor for the onset and exacerbation of serious bowel conditions such as IBS and inflammatory bowel diseases (IBD), Crohn’s disease and ulcerative colitis.