What is IBS? Symptoms, Causes, and How to Know I Have It?

Irritable Bowel Syndrome (IBS) is surprisingly common, with it being estimated that an astounding 10-15% of the world’s population now suffer from it. IBS is a functional gut disorder, which means that when doctors run diagnostic tests, they won’t usually find anything structurally wrong with the gut.

This can be incredibly frustrating, as the symptoms can be really debilitating and have a huge impact our lives. In fact, one study found that people with IBS were willing to give up 25% of their remaining life expectancy (an average of 15 years!) to be free from symptoms (Drossman et al., 2009).

What are IBS symptoms?

IBS is diagnostically characterised by the presence of any of the following symptoms for at least 6 months, in the absence of physical causes:

• abdominal pains or discomfort

• bloating

• change in bowel habits (e.g diarrhoea, constipation, or both)

Other possible symptoms also include:

• Excess wind

• Nausea

• Back pain

• Brain fog

• Fatigue

However, IBS symptoms are very unique to each individual – symptoms can be mild or severe, chronic or sporadic, wide-ranging, or limited to just one problematic symptom. That’s why the latest IBS clinical guidelines, advocates a personalised and holistic approach to IBS, which tackles’ people’s own unique symptoms with tailored lifestyle, wellbeing and dietary advice (Vasant et al, 2021). For further reading about a holistic approach to IBS, click here.

How do I get diagnosed with IBS?

There are no tests that identify IBS, it’s diagnosed through ruling out other conditions first. Your GP should carry out basic investigations such as:

• Blood tests to rule out Coeliac disease

• Stool tests to exclude Inflammatory Bowel Disease

• In some cases, you will be referred to the Gastroenterology team for an endoscopy or colonoscopy (cameras either end to investigate).

Red Flags: When Should I Seek Help From a Doctor?

IBS symptoms can also sometimes indicate other gut disorders, so it’s really important to go to your GP first, before seeking any other help. If you experience any of the following symptoms, it’s absolutely essential to see your GP, as they may indicate something more serious than IBS:

• Blood in the stool

• Anaemia

• Unintentional weight loss

• Fever

• Symptoms that are severe or getting progressively worse

• Bowel movements waking you up through the night

• Having a family history of other bowel diseases

What causes IBS?

The exact cause of IBS isn’t fully understood, but research shows that it’s usually the result of several overlapping factors rather than a single trigger. For some people, IBS develops because of visceral hypersensitivity - a heightened sensitivity in the gut, meaning even normal digestive processes can feel painful or uncomfortable (read more about this here). In others, symptoms may be linked to changes in the gut microbiome, sometimes following a stomach infection or course of antibiotics.

Another common contributor is altered gut motility, where food moves too quickly or too slowly through the digestive tract, leading to diarrhoea, constipation, or both. The gut–brain connection also plays a big role: we’re now acknowledging that stress, anxiety and our nervous system has a big impact on the physiological processes of our digestive system. This is why mind-body approaches like CBT, mindfulness and hypnotherapy, which help calm the nervous system can be really effective in reducing IBS symptoms.

Dietary and lifestyle factors add another layer of complexity. Excess alcohol, caffeine, or a diet high in processed foods can irritate the gut and exacerbate symptoms. On the other hand, not everyone with IBS reacts in the same way - some may struggle with high-fibre, plant-based foods rich in prebiotics, as these can ferment in the gut and increase gas, while others may actually benefit from them once their digestive system adapts. Similarly, foods high in FODMAPs (fermentable carbohydrates) can trigger symptoms in many people, but tolerance levels vary widely (read more about the low FODMAP diet here).

Because IBS is so individual, treatment usually focuses on identifying which of these factors are most relevant for you. For some, reducing stress through relaxation techniques is key; for others, making adjustments to dietary and lifestyle patterns makes the biggest difference.

What are the best IBS treatments?

There’s currently no cure for IBS, and no single medication works for everyone. Some medication can help manage specific symptoms like abdominal pains, diarrhoea or constipation, but they don’t address the condition as a whole and they often come with side effects. Interestingly, research shows that people with IBS often respond strongly to placebo treatments, highlighting the powerful role of the brain–gut connection (Kaptchuk et al, 2010). This may explain why mind-body approaches such as CBT, hypnotherapy, and mindfulness can be so effective in reducing IBS symptoms - it’s about supporting the gut and brain together. Because IBS is so individual, the most effective treatments often combine dietary changes, lifestyle strategies, and mind-body therapies. Evidence-based options include:

• Dietary approaches

  • Low FODMAP diet (short-term, structured under professional guidance)

  • Increasing fibre for some types of IBS

  • Identifying individual food triggers

• Mind-body therapies

  • Cognitive behavioural therapy (CBT)

  • Gut-directed hypnotherapy

  • Mindfulness and relaxation techniques

• Lifestyle strategies

  • Regular movement

  • Prioritising sleep

  • Stress reduction and nervous system regulation

Key Takeaways

IBS can have a huge impact on our quality of life, but with proper management and lifestyle changes, symptoms can often be alleviated. If you suspect you may have IBS, it's essential to seek medical advice for an accurate diagnosis. Managing IBS involves a combination of dietary & lifestyle modifications, stress management techniques and sometimes counselling or therapy. I would recommend working with a healthcare professional, like myself, who can give you an personalised treatment plan tailored to your individual needs. Please don’t hesitate to reach out for support and guidance on managing your symptoms effectively. For further information about my services, click here.

References

Drossman, D.A., Morris, C.B., Schneck, S., Hu, Y.J., Norton, N.J., Norton, W.F., Weinland, S.R., Dalton, C., Leserman, J., Bangdiwala, S.I. (2009) International survey of patients with IBS: symptom features and their severity, health status, treatments, and risk taking to achieve clinical benefit. Journal of Clinical Gastroenterology, 43(6), pp.541–550. Link

Kaptchuk, T.J., Friedlander, E., Kelley, J.M., Sanchez, M.N., Kokkotou, E., Singer, J.P., Kowalczykowski, M., Miller, F.G., Kirsch, I., Lembo, A.J. (2010) ‘Placebos without deception: A randomized controlled trial in irritable bowel syndrome’, PLoS ONE, 5(12), e15591. doi: 10.1371/journal.pone.0015591 Link

National Institute for Health and Care Excellence (NICE). (2008) Irritable bowel syndrome in adults: diagnosis and management. Clinical guideline CG61. Available at: https://www.nice.org.uk/guidance/cg61 [Accessed 4 September 2025]

Vasant, D.H., Paine, P.A., Black, C.J., Houghton, L.A., Everitt, H.A., Corsetti, M., Agrawal, A., Aziz, I., Farmer, A.D., Eugenicos, M.P., Moss-Morris, R., Yiannakou, Y., Ford, A.C. (2021) British Society of Gastroenterology Guidelines on the Management of Irritable Bowel Syndrome. Gut, 70(7), pp.1214–1240. doi: 10.1136/gutjnl-2021-324598 Link