Lancet. 1989 Feb 25;1(8635):424-5.
Individual and group hypnotherapy in treatment of refractory irritable bowel syndrome.
This study employed a shorter hypnosis treatment course for IBS than used in most other studies. Twenty out of 33 patients with refractory irritable bowel syndrome treated with four sessions of hypnotherapy in this study improved. Improvement was maintained at a 3-month treatment. The researchers further found that hypnosis treatment for IBS in groups of up to 8 patients seemed to be as effective as individual therapy.
33 patients with refractory irritable bowel syndrome were treated with four 40-minute sessions of hypnotherapy over 7 weeks. 20 improved, 11 of whom lost almost all their symptoms. Short-term improvement was maintained for 3 months without further formal treatment. Hypnotherapy in groups of up to 8 patients was as effective as individual therapy.
Link to full paper with PMID: 2563797