Hypnotherapy for persons with Irritable Bowel Syndrome: A three-arm randomized controlled trial

Abstract

Previous studies have shown the efficacy of traditional hypnotherapy (TH) for irritable bowel syndrome (IBS). Rigorous evaluation of integrative hypnotherapy (IH) is awaited. The current study aimed at (1) comparing the efficacy of IH, TH and educational talk (ET), and (2) evaluating the impacts hypnotic susceptibility on participants’ responses to hypnotherapy. The study adopted a 3-arm randomized controlled trial design and achieved an effective sample size of 144. Measures were taken at pre-test (T0), post-test (T1), and 3 months after intervention (T2). Primary outcomes were IBS symptoms severity (IBSSS) and mental/physical component score of health-related quality of life (MCS/SF-12, PCS/SF-12). Secondary outcomes were illness coping patterns - symptoms catastrophizing (SC) and Symptom-related social hypervigilance (SSH). Multivariate and univariate ANOVA revealed significant group x time interaction effects in all the outcome variables, except PCS/SF-12: partial eta squared for IBSSS, MCS/SF-12, SC and SSH were 0.20, 0.05, 0.14 and 0.45 respectively, which were at magnitudes of medium to large effect size. At T1, there was significant difference between groups (Fs > 4.50, p < .05). Within-group analyses showed an superior improvement in IBSSS, MSC/SF-12, SC and SSH in IH group. At T2, similar pattern was revealed. Higher hypnotic susceptibility appeared to predict better treatment responses in TH group, but showed no impacts on treatment responses in IH group. In conclusion, the findings support the efficacy of both IH and TH for IBS. Overall IH appeared to be superior to TH. Persons with higher hypnotic susceptibility may benefit more from TH. Keywords: Hypnotherapy; Irritable bowel syndrome; Randomized controlled trial, Symptom +control, Quality of life, Hypnotic susceptibility, Coping responses, Symptoms catastrophizing, Symptom-related social hypervigilance