Gut-directed hypnotherapy for IBS: the IMAGINE trial and the diet comparison

Study at a glance

Flik and colleagues ran the largest randomised trial of gut-directed hypnotherapy to date, enrolling 354 IBS patients referred from Dutch primary and secondary care and allocating them 3:3:1 to six sessions of individual hypnotherapy, group hypnotherapy, or group educational supportive therapy. Hypnotherapy was more effective than the educational control at both three months (odds ratio 2.9) and twelve months (OR 2.8), and group hypnotherapy was non-inferior to one-to-one sessions. The absolute response rates, around 40% versus 17% to 23% for control, are good for IBS but leave most patients without adequate relief.

What they did

Patients aged 18 to 65 with IBS were recruited across 11 Dutch hospitals between 2011 and 2016 and randomised in blocks by staff not involved in treatment: 150 to individual hypnotherapy, 150 to group hypnotherapy, and 54 to the educational control. The primary outcome was adequate relief of IBS symptoms, with responders defined as those reporting adequate relief on at least three of four consecutive weekly assessments. Hypnotherapy (both arms pooled) was compared with control in an intention-to-treat population; non-inferiority of group versus individual hypnotherapy was tested per protocol with a 15% margin, at 3 and 12 months. The trial was registered (ISRCTN22888906).

A smaller Australian trial by Peters and colleagues (PMID: 27397586) asked a different question, randomising 74 patients to hypnotherapy, the low FODMAP diet, or both, with change in overall gastrointestinal symptoms at six weeks as the primary endpoint.

What they found

After excluding people later found ineligible, 142 individual-hypnotherapy, 146 group-hypnotherapy and 54 control patients were analysed. Dropout before or during therapy was 15%, 15% and 20% respectively. At three months the adequate-relief rate was 40.8% with individual hypnotherapy, 33.2% with group hypnotherapy and 16.7% with control; at twelve months it was 40.8%, 49.5% and 22.6%. Pooled hypnotherapy beat control at both timepoints (OR 2.9, 95% CI 1.2 to 7.4, p = 0.024; OR 2.8, 95% CI 1.2 to 6.7, p = 0.019). In the per-protocol analysis, group hypnotherapy met the non-inferiority margin against individual treatment (42.7% vs 49.9% at 3 months, 51.7% vs 55.5% at 12 months). Eight serious adverse events, mostly cancer or inflammatory bowel disease diagnoses, were judged unrelated to therapy.

In the Peters trial, all three arms improved similarly at six weeks (mean symptom change of -33, -30 and -36 points on a visual analogue scale, p = 0.67 between groups), with 72%, 71% and 72% achieving a 20 mm improvement. Hypnotherapy produced larger improvements in trait anxiety and depression than the diet, and the combination offered no additive benefit. A 2020 network meta-analysis of 41 psychological-therapy trials (4,072 participants) found gut-directed hypnotherapy reduced the risk of remaining symptomatic (RR 0.67, 95% CI 0.49 to 0.91), alongside CBT, but warned that high risk of bias and funnel-plot asymmetry likely inflate all such estimates (PMID: 32276950).

Strengths

• Scale and setting. Most hypnotherapy evidence comes from a single specialist centre treating refractory patients; IMAGINE was multicentre, recruited from primary and secondary care, and used therapists outside the founding group.
• An active control. Educational supportive therapy delivered in groups controls for attention, time and group contact, which a waiting list does not.
• Twelve-month follow-up with persistence of benefit, and a pre-specified non-inferiority test for group delivery that has obvious implications for access and cost.
• Registered, with intention-to-treat analysis for the main comparison.

Limitations

• Blinding is impossible. Participants knew whether they were being hypnotised or educated, and the outcome is entirely self-reported. Expectation effects in IBS are large; the roughly 17% to 23% control response is at the low end of the 30 to 40% placebo rates seen in drug trials, which hints that the control arm may have been less convincing than a pill.
• The control arm was small (54 patients), so the odds ratios carry wide confidence intervals (lower bounds of 1.2).
• Non-inferiority was tested per protocol, which is standard but excludes the 15% who dropped out; the intention-to-treat numbers at 3 months (33% group vs 41% individual) look less equal.
• The Peters trial had about 25 patients per arm, no control arm, and a six-week primary endpoint; “similar to low FODMAP” is a comparison between two active treatments, not evidence that either beats placebo.
• Generalisability to people who cannot access trained gut-directed hypnotherapists, or to those sceptical of hypnosis, is unknown; trial participants had all accepted a referral for psychological treatment.
• The network meta-analysis explicitly notes that small, biased trials dominate the psychological-therapy literature.

What it means

The evidence suggests gut-directed hypnotherapy may help a meaningful minority of people with IBS, that the benefit can persist for a year, and that group delivery is a credible, cheaper alternative to one-to-one sessions. The 2021 ACG guideline files hypnotherapy under gut-directed psychotherapies and suggests them conditionally on very-low-quality evidence, which is a fair summary: consistent signal, weak methods.

Readers should not take the 40 to 50% response rates as the share who will feel better because of hypnosis specifically; some of that is expectation and time. They should also note that most trial participants still did not reach adequate relief. Hypnotherapy is low-risk and does not interact with medication, so for someone whose symptoms track with stress or who wants to avoid drugs it is worth raising with a clinician, ideally one who can point to a therapist trained in a gut-directed protocol.

References

• Flik CE, Laan W, Zuithoff NPA, et al. Efficacy of individual and group hypnotherapy in irritable bowel syndrome (IMAGINE): a multicentre randomised controlled trial. Lancet Gastroenterol Hepatol. 2019. PMID: 30473202
• Peters SL, Yao CK, Philpott H, et al. Randomised clinical trial: the efficacy of gut-directed hypnotherapy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2016. PMID: 27397586
• Black CJ, Thakur ER, Houghton LA, et al. Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2020. PMID: 32276950