Objective: To assess the efficacy, tolerability, and safety of hypnosis in adult irritable bowel syndrome by a meta-analysis of randomized controlled trials.
Methods: Studies were identified by a literature search of the databases Allied and Complementary Medicine Database, Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, PubMed, PsycINFO, and Scopus (from inception to June 30, 2013). Primary outcomes were adequate symptom relief, global gastrointestinal score, and safety. Summary relative risks (RRs) with number needed to treat (NNT) and standardized mean differences (SMDs) with 95% confidence intervals (95% CIs) were calculated using random-effects models.
Results: Eight randomized controlled trials with a total of 464 patients and a median of 8.5 (7-12) hypnosis sessions over a median of 12 (5-12) weeks were included into the analysis. At the end of therapy, hypnosis was superior to control conditions in producing adequate symptom relief (RR, 1.69 [95% CI = 1.14-2.51]; NNT, 5 [3-10]) and in reducing global gastrointestinal score (SMD, 0.32 [95% CI = -0.56 to -0.08]). At long-term follow-up, hypnosis was superior to controls in adequate symptom relief (RR, 2.17 [95% CI = 1.22-3.87]; NNT, 3 [2-10]), but not in reducing global gastrointestinal score (SMD, -0.57 [-1.40 to 0.26]). One (0.4%) of 238 patients in the hypnosis group dropped out due to an adverse event (panic attack).
Conclusion: This meta-analysis demonstrated that hypnosis was safe and provided long-term adequate symptom relief in 54% of patients with irritable bowel syndrome refractory to conventional therapy.