Authors: Christopher J. Black and Alexander C. Ford
Journal: Expert Review of Gastroenterology & Hepatology
Year: 2025
Volume: 19
Pages: 227–242
DOI: 10.1080/17474124.2025.2455586
Study at a glance
- Study type: Expert review
- Population studied: Adults with irritable bowel syndrome
- Intervention or approach studied: Diagnostic approaches and treatment strategies for irritable bowel syndrome
- Main outcome(s): Accuracy of diagnostic criteria, efficacy of dietary advice, probiotics, drugs for constipation and diarrhoea, drugs for abdominal pain, and psychological therapies
Why was this study done?
Irritable bowel syndrome (IBS) is a disorder of gut and brain interaction affecting around 5% of the population. People with IBS experience abdominal pain with changes in stool frequency or form. Despite progress in understanding diagnosis and treatment, many doctors still view IBS as a diagnosis of exclusion. Black and colleagues reviewed medical literature from 2020 to 2024 to provide an evidence-based update on IBS diagnosis and management, focusing on diagnostic accuracy studies, randomised controlled trials, and meta-analyses.
How was the study performed?
The authors examined symptom-based diagnostic criteria accuracy and when investigations should exclude other conditions. They reviewed the Rome IV criteria, the current gold standard requiring abdominal pain at least once weekly for three months, with two or more features: pain related to defecation, pain with change in stool frequency, or pain with change in stool form. Symptoms must have been present for six months. They also reviewed evidence for dietary interventions, probiotics, drugs targeting constipation or diarrhoea, drugs for abdominal pain, and psychological therapies.
What did the researchers find?
Rome IV criteria performed better than previous versions, with patients meeting criteria almost five times more likely to have IBS than another condition. After four years, only 1% of patients diagnosed using Rome IV criteria and limited investigation were found to have another condition.
All patients should be tested for coeliac disease, as odds were two to three times higher in those with IBS symptoms. Faecal calprotectin should be requested in patients under 45 years with IBS and diarrhoea to exclude inflammatory bowel disease. Colonoscopy has extremely low yield; one study of 466 patients found only 0.4% had inflammatory bowel disease, 1.5% had microscopic colitis, and no bowel cancer.
Traditional dietary advice (regular meals, reduced caffeine and alcohol, adequate hydration) should be offered first. If symptoms persist, referral to a specialist dietitian for a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet should be considered. This diet ranked first for improving global IBS symptoms, abdominal pain, bloating, and bowel habit.
A review of 82 probiotic trials found overall benefit, although evidence quality was very low.
For constipation, laxatives should be used first, then secretagogues such as linaclotide if ineffective. For diarrhoea, loperamide should be used first, although evidence was conflicting. Second-line treatments include 5-hydroxytryptamine-3 receptor antagonists, eluxadoline, or rifaximin, with alosetron and ramosetron appearing most effective.
For abdominal pain, antispasmodic drugs or peppermint oil should be used first. Where ineffective, tricyclic antidepressants should be prescribed. A trial of 463 participants found low-dose amitriptyline (10 mg to 30 mg daily) superior to placebo at six months.
Brain and gut behavioural therapies are effective, including in patients not responding to medical treatments. A review of 41 trials found cognitive behavioural therapy and gut-directed hypnotherapy most efficacious long term.
What did the authors conclude?
A positive diagnostic approach using symptom-based criteria with limited investigation should be preferred. Coeliac disease should be excluded in all patients, with faecal calprotectin testing in those under 45 years with diarrhoea. Traditional dietary advice should be provided, with specialist dietitian referral if unsuccessful. Laxatives, loperamide, and antispasmodics or peppermint oil should be first-line for constipation, diarrhoea, and pain respectively. Second-line options include secretagogues, 5-hydroxytryptamine-3 receptor antagonists, and low-dose tricyclic antidepressants. Brain and gut behavioural therapies can be considered for persistent symptoms. Despite substantial advances, reinforcement of positive diagnostic strategies and novel treatment approaches are required.
Key takeaways
- IBS can be diagnosed safely using symptom-based criteria and limited investigation, including tests to exclude coeliac disease and, in patients with diarrhoea under 45 years, a faecal calprotectin test to exclude inflammatory bowel disease.
- Traditional dietary advice should be offered first, with referral to a specialist dietitian to consider a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols if symptoms persist.
- Laxatives should be used first for constipation, loperamide for diarrhoea, and antispasmodic drugs or peppermint oil for abdominal pain.
- Where first-line treatments are ineffective, secretagogues can be used for constipation, drugs that block the 5-hydroxytryptamine-3 receptor for diarrhoea, and low-dose tricyclic antidepressants for abdominal pain.
- Brain and gut behavioural therapies, such as cognitive behavioural therapy or gut-directed hypnotherapy, are effective for managing symptoms in IBS, including in patients whose symptoms are resistant to standard treatments.
This Scientific Publication Summary is an objective summary of the published study for personal and educational use. It does not constitute medical advice, endorsement of the intervention, or a recommendation to alter clinical practice.