IBS isn't all in your head: the gut–brain connection

Irritable bowel syndrome (IBS) is a condition involving the interaction between the digestive system and the brain. Although symptoms are experienced in the gut, the processes contributing to them involve much more than digestion.

For people who have spent months or years changing their diet, avoiding foods, or undergoing investigations without clear answers, the gut–brain connection offers another way to make sense of persistent symptoms.

A disorder of gut–brain interaction

IBS is classified as a disorder of gut–brain interaction (DGBI). This reflects the two-way communication between the digestive system and the central nervous system.

The gut and brain communicate continuously through neural, hormonal and immune pathways. These systems regulate intestinal movement, digestive secretions, sensitivity and responses to stress.

In IBS, several processes may be involved, including:

• Visceral hypersensitivity: increased sensitivity to sensations within the digestive tract, so that normal activity may feel uncomfortable or painful.
• Altered gastrointestinal motility: changes in how quickly or slowly contents move through the digestive system, contributing to diarrhoea, constipation or both.
• Changes in central pain processing: differences in how the brain and nervous system process signals originating in the gut.
• Altered gut microbiota and immune activity: factors contributing to symptoms in some individuals.

These processes don't all produce structural abnormalities detectable through routine investigations, so normal test results are common. This does not mean that digestive symptoms are imaginary or insignificant.

How stress and emotional experiences influence digestion

During periods of stress, the body activates physiological responses designed to manage perceived demands or threats. These involve changes in nervous system activity and stress-related hormonal signalling, affecting intestinal movement, sensitivity and digestive sensations.

This helps explain why some people experience abdominal discomfort before an important event, changes in bowel habits during emotionally difficult periods, or improved digestion when everyday pressures are reduced.

Stress does not cause every case of IBS, but it contributes to symptom severity and persistence in many individuals. Keeping a simple record of symptoms alongside stress, sleep and emotionally significant events, not just food, can help show whether these relationships apply to you.

Psychological influences do not make physical symptoms imaginary

The distinction between physical and psychological health is often misleading when discussing IBS. Thoughts, emotions and responses to stress involve physiological activity within the brain and nervous system. These processes directly affect bodily functions, including digestion.

When emotional experiences contribute to abdominal pain, diarrhoea or constipation, the resulting symptoms remain physical and real. Psychological factors are not an alternative to physiological explanations. They form part of those explanations.

The influence of longer-term stress and personal experiences

The effects of stress on digestion are not limited to immediate stressful situations. Prolonged stress influences the body’s stress-response systems and may contribute to changes in gastrointestinal sensitivity and gut–brain communication.

Research has also identified associations between adverse early-life experiences and an increased likelihood of developing disorders of gut–brain interaction.

This does not mean that IBS is necessarily caused by trauma or difficult past experiences. IBS is multifactorial, and many people experience the condition without a history of significant psychological adversity. 

Nevertheless, personal history and longstanding patterns of responding to stress deserve consideration when exploring an individual’s symptoms.

Dietary changes may not resolve every symptom

Nutrition is an important component of IBS management. Adjustments to fibre intake and, where appropriate, a structured low-FODMAP intervention are effective for some people, and identifying individual triggers can bring meaningful relief.

Soluble fibre, such as psyllium, is often helpful, whereas wheat bran can make symptoms worse. The low-FODMAP diet involves restriction, reintroduction and personalisation, ideally with professional support, rather than long-term restriction.

However, when altered pain processing, heightened gut sensitivity or stress-related physiological responses contribute to symptoms, dietary changes alone will not address all the mechanisms involved.

When these factors remain unexplored, some people resort to further food restrictions, unnecessarily narrowing their diet and increasing the risk of nutritional gaps. This can also increase anxiety around food, potentially reinforcing the very stress responses contributing to their symptoms.

Exploring emotional patterns and the gut–brain connection

Gut-directed hypnotherapy and cognitive behavioural therapy (CBT) adapted for IBS are established approaches that help reduce the severity and impact of symptoms. They work by helping people change how they interpret and respond to gut sensations, using techniques such as guided relaxation, imagery and changes in thought and behaviour patterns.

But there is another aspect of the gut–brain connection worth exploring: the emotional experiences, learned responses and longstanding patterns that shape how someone responds to stress.

Someone may understand intellectually that they struggle to express anger or regularly put other people’s needs before their own. Recognising these patterns, or learning techniques to manage their responses, does not always change what’s underneath them.

In relational and somatic work, we explore what happens emotionally and physically in the moment. What sensations appear in the body? What feelings emerge? What happens when someone begins to express something they would ordinarily suppress? And, where relevant, how might these responses connect to earlier experiences, relationships or learned ways of coping? 

Within a supportive therapeutic relationship, this work aims to develop greater emotional awareness and flexibility in responding to stress. Bringing this together with nutritional therapy allows us to address both digestive and emotional factors.

For example, someone whose symptoms flare after meals might find that certain foods play a part, but also that symptoms worsen when eating in a rush or after conversations in which they held back what they felt. Working with both can address more of what is contributing to their IBS symptoms.

A more integrated approach to digestive health

Not everyone needs psychological therapy or an exploration of their past. But when dietary changes haven’t provided the answers you were hoping for, understanding the gut–brain connection and the patterns behind your symptoms can offer another way of exploring them, and of finding the support that suits you best.

References

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Murray HB, Bailey AP, Keshishian AC, et al. Prevalence and characteristics of avoidant/restrictive food intake disorder in adult neurogastroenterology patients. Clinical Gastroenterology and Hepatology. 2020;18(9):1995–2002.

Black CJ, Thakur ER, Houghton LA, et al. Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2020;69(8):1441–1451.

Thakur ER, Holmes HJ, Lockhart NA, et al. Emotional awareness and expression training improves irritable bowel syndrome: a randomized controlled trial. Neurogastroenterology & Motility. 2017;29(12):e13143.