Beyond symptom improvement: what do different gut–brain therapies actually change?

A major new review of IBS has just been published in Nature Reviews Disease Primers.

The authors describe IBS as involving disrupted communication between the gut and brain, with the body’s stress systems playing an important role.

Two findings stood out, particularly because they relate to my work:

People with adverse childhood experiences are approximately twice as likely to develop IBS.

Early-life experiences help shape communication between the brain, gut and microbiome.

Now consider the two main psychological therapies discussed in the Primer: cognitive behavioural therapy (CBT) and gut-directed hypnotherapy (GDH).

CBT primarily targets symptom-related anxiety, fear, avoidance and unhelpful illness beliefs. GDH uses focused attention, imagery and therapeutic suggestion to influence gut function, visceral sensitivity and autonomic arousal.

Both have good evidence behind them, and the authors report sustained improvements in IBS symptoms and quality of life. They suggest that the quality-of-life benefits, particularly of CBT, arise primarily through changes in symptom-related anxiety and illness beliefs rather than direct changes in gastrointestinal or autonomic physiology.

From this article and the wider literature, it remains unclear whether these therapies reliably produce lasting changes in the underlying stress-response systems themselves.

Another issue is that not all gut–brain therapies are the same, even when they share a label.

GDH, for example, can be delivered through standardised digital programmes, which offer an accessible, evidence-based way of managing symptoms.

Working individually with a therapist, whether through hypnotherapy or other forms of therapy, may offer something additional: the opportunity to adapt treatment as it unfolds and, depending on the therapist’s way of working, to explore emotional responses, recurring patterns and personal experiences within a therapeutic relationship.

For people whose stress-response systems have been shaped by early-life experiences, could more exploratory and relational therapy help address the underlying patterns contributing to their IBS, beyond managing symptoms and reducing arousal? And might that influence whether improvements persist or symptoms return, even years later?

What I’d really like to see at this stage is research that maps this terrain: Not simply trials asking which approach produces the greatest average improvement, but rather what different therapies actually target, how they work, and which patients might benefit from one therapeutic process rather than another.