Inflammatory bowel disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (ULC), is a refractory disease with repeated remission and exacerbation of symptoms. The etiology of IBD is unknown, but multiple factors may be associated with its pathogenesis. Several reports indicate that environmental factors, such as smoking, diet, infections, poor sleep, stress and medication, affect the disease course by interacting with genetic susceptibility and impaired immune system responses. The sum of these environmental factors during the lifetime, termed the “exposome”, appears to be associated with the pathogenesis of IBD. Other environmental factors, such as psychologic stress and sleep condition, may also be associated with the IBD disease course: IBD patients are significantly more depressive than healthy controls and psychologic stress is associated with an exacerbation of IBD symptoms.
A new study, published in the journal Gut, has found depression is more common among people with Crohn’s disease or ulcerative colitis in the years before they are diagnosed with these bowel conditions. Researchers from St George’s, University of London, Imperial College London, University College London and King’s College London studied the records of 15.000 people with ulcerative colitis and Crohn’s disease, collectively known as inflammatory bowel diseases or IBD. They found patients were more likely to be diagnosed with depression up to 9 years before the diagnosis of their IBD compared with people who did not go on to be diagnosed with the condition. IBD can result in abdominal pain, diarrhoea or rectal bleeding and many people live with these gastrointestinal symptoms for years before being diagnosed. This study examined the link between depression and the chance of later developing IBD.
Using the Clinical Practice Research Datalink identifying incident cases of ULC and Crohn from 1998 to 2016, researchers identified 10 829 ULC cases, 4531 CD cases and 15 360 controls. There was an excess of prevalent depression 5 years before IBD diagnosis relative to controls (ULC: 3.7% vs 2.7%, CD 3.7% vs 2.9%). Individuals with GI symptoms prior to the diagnosis of depression had increased adjusted risks of developing ULC and CD compared with those without depression. People who reported GI symptoms before developing depression were 40% more likely to develop IBD compared with people without depression. The study suggests that, on its own, depression is not a risk factor for developing IBD. However, people with depression and previous gastrointestinal symptoms may be more likely to develop the conditions.
Senior Author Richard Pollok, Professor of Gastroenterology, St George’s, University of London, commented: “The relationship between depression and IBD is unclear, but it is likely some individuals develop depression as a consequence of gastrointestinal symptoms they experience before being diagnosed with IBD. If you are experiencing depression with abdominal pain, diarrhoea or rectal bleeding, see your doctor and get tested because there may be a treatable cause. It is possible people become depressed while living with undiagnosed gut symptoms of Crohn’s disease or ulcerative colitis. Now, more than ever, during the COVID-19 pandemic it is vital to put strategies in place to ensure timely diagnosis of these bowel conditions to protect people’s physical and mental health.”
- edited by Dr. Gianfrancesco Cormaci, PhD; specialist in Clinical Biochemistry.
Scientific references
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