Nerva IBS randomized controlled trial: evidence and outcomes

The primary endpoint was the proportion of participants whose IBS Symptom Severity Scale score fell by at least 50 points at program completion. This is a threshold for meaningful improvement in a symptom score, rather than a measure of whether someone was cured.

What were the results?

At program completion, 81% in the hypnotherapy group met the primary endpoint, compared with 63% in the active-control group (P = .002).

A reduction of at least 30% in abdominal pain was reported by 71% versus 35%, respectively (P < .001). Quality of life improved more with hypnotherapy. Psychological status improved similarly in both groups.

These are different outcomes. The 81% figure is not an 81% reduction in symptoms, and the 71% figure refers to a defined pain-response threshold. Neither percentage is a guarantee about an individual person's experience.

How should the findings be interpreted?

The trial provides controlled evidence for digitally delivered gut-directed hypnotherapy within Nerva's brain-gut behavioral approach. Its active comparison matters: both groups received a digital program, and the group receiving hypnotherapy had a higher symptom-response rate.

The findings apply to the intervention studied in adults with IBS. The population was predominantly female. The trial did not compare Nerva with Oshi, Cylinder, Ayble or a low-FODMAP diet, and it did not separately evaluate every component of today's broader care program.

The study included follow-up after the program. The primary result described here is the comparison at program completion; it should not be relabeled as a six-month response rate.

Is this the same as the 2016 low-FODMAP study?

No. Peters and colleagues' 2016 trial compared therapist-delivered gut-directed hypnotherapy, a low-FODMAP diet and their combination. It did not test the Nerva app. It is evidence about those approaches, while the Anderson trial provides evidence about the digital Nerva study program.

From clinical evidence to personalized digestive care

Nerva is a personalized digital digestive care program combining clinical screening, brain-gut behavioral care, dietary guidance, symptom tracking and escalation when needed. It includes a six-week core program and continued maintenance access. Gut-directed hypnotherapy is one component of its brain-gut behavioral care. Explore the full care program and watch the demo.

Bring evidence-supported brain-gut behavioral care into your patients' digestive care. See how to refer a patient to Nerva.

For other publications and study summaries, visit Nerva's research library.

References

1. Anderson EJ, Peters SL, Gibson PR, Halmos EP. Comparison of Digitally Delivered Gut-Directed Hypnotherapy Program With an Active Control for Irritable Bowel Syndrome. American Journal of Gastroenterology. 2025;120(2):440–448. Published online 28 June 2024. PubMed study abstract. doi:10.14309/ajg.0000000000002921.

2. Peters SL, Yao CK, Philpott H, Yelland GW, Muir JG, Gibson PR. 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. Alimentary Pharmacology & Therapeutics. 2016;44(5):447–459. PubMed study abstract.