Table 1.

Relevant studies supporting the utility of hypnotherapy in IBS treatment.

STUDY	OBJECTIVES OF THE STUDY	RESULTS
Whorwell et al. [202]	30 patients with severe refractory IBS were randomly allocated to treatment with either hypnotherapy or psychotherapy and placebo.	The psychotherapy produced a small improvement in abdominal pain, abdominal distension, and general well-being but not in bowel habit. The hypnotherapy presented a dramatic improvement in all features and no relapses were recorded during the 3-month follow-up period.
Donnet et al. [194]	Recorded 150 IBS patients' perceptions and expectations of hypnotherapy as well as their symptom response.	Hypnotherapy improved symptoms and resulted in a wide range of additional benefits. Expectation did not necessarily influence the outcome. Recording IBS symptoms alone does not fully capture the patient's experience of treatment.
Sasegbon et al. [182]	Forty-four Asian patients with refractory IBS received 12-sessions of gut-directed hypnotherapy (GDH) using the Manchester protocol.	GDH was highly effective with similar response rates to outcomes in other IBS populations regardless of the ethnicity of the therapist.
Hasan et al. [183]	Randomized study of gut-focused hypnotherapy (GFH). 450 subjects with IBS were allocated to either 6 or 12 weekly sessions.	Compared with 12 sessions, 6 sessions of GFH produced similar levels of improvement in IBS symptoms, noncolonic symptoms, anxiety, depression, and quality of life.
Hoekman et al. [85]	Randomized, controlled, open-label trial to compare the effectiveness of hypnotherapy vs standard medical treatment (SMT) for IBS- type symptoms in 80 IBD patients.	The effectiveness of SMT and hypnotherapy for IBS-type symptoms was comparable in IBD patients.
Black et al. [184]	Searching the medical literature through January 2020 for randomized controlled trials assessing the efficacy of psychological therapies for adults with IBS, compared with each other or a control intervention.	Several psychological therapies are efficacious for IBS, although none were superior to another. CBT (cognitive behavioral therapy)- based interventions and gut-directed hypnotherapy had the largest evidence base and were the most efficacious long term.
Vasant et al. [185],	32 young patients with IBS received 12 sessions of gut-focused hypnotherapy (GFH).	GFH was very effective in children and adolescents with IBS. Early intervention with GFH in childhood IBS may reduce the subsequent burden of this problem in adults.
Rutten et al. [199]	A systematic review to compare the effectiveness of gut-directed hypnotherapy (GDH) by means of home-based self-exercises using an audio CD with that of individual hypnotherapy (iHT) performed by qualified therapists. 132 children were assigned to the CD group and 128 to the iHT group.	The long-term effectiveness of home-based hypnotherapy with an audio CD is noninferior to iHT performed by therapists in pediatric IBS or functional abdominal pain (FAP). Treatment with hypnosis using an audio CD provides an attractive treatment option for these children.
Peters et al. [186]	A review of published literature and a systematic review of clinical trials about gut- directed hypnotherapy.	Gut-directed hypnotherapy has durable efficacy in patients with IBS and possibly ulcerative colitis.
Miller et al. [195]	1000 consecutive patients with IBS received 12 sessions of hypnotherapy over 3 months.	The results of this audit confirmed that 3 months of hypnotherapy produced significant improvement in symptoms in this large group of refractory IBS patients, who were continuing to experience troubling symptoms despite multiple conventional interventions.
Gerson et al. [187]	Testing whether group gut-focused hypnotherapy would improve IBS in 75 patients.	The group hypnotherapy was effective in patients with IBS.
Rutten et al. [196]	A systematic review to assess the efficacy of gut-directed hypnotherapy in pediatric functional abdominal pain (FAP) and IBS patients.	The therapeutic effects of HT seem superior to standard medical care in children with FAP or IBS. It remains difficult to quantify the exact benefits. The need for more high-quality research is evident.
Lindfors et al. [188]	208 patients received gut-directed hypnotherapy that was retrospectively evaluated.	This long-term follow-up study indicated that gut-directed hypnotherapy in refractory IBS is an effective treatment option with long- lasting effects, also when given outside highly specialized hypnotherapy centers.
Vlieger et al. [197]	This follow-up study investigated the long- term effects of gut-directed hypnotherapy vs. standard medical treatment plus standard supportive therapy (SMT) in 52 participants.	This follow-up study clearly demonstrated that the beneficial effects of gut-directed hypnotherapy are sustained over a period of 5 years in children with functional abdominal pain (FAP) or IBS.
Vlieger et al. [189]	53 pediatric patients, aged 8–18 years, with functional abdominal pain (FAP) or IBS, were randomized to either hypnotherapy or standard supportive therapy (SMT).	Hypnotherapy was more effective, with a significantly greater reduction in pain scores compared with SMT.
Gonsalkorale et al. [191]	204 patients prospectively completed questionnaires scoring symptoms, quality of life, anxiety, and depression before, immediately after, and up to six years following hypnotherapy.	This study demonstrated that the beneficial effects of hypnotherapy for IBS last at least five years.
Palsson et al. [193]	Patients with severe IBS received seven biweekly hypnosis sessions and used hypnosis audiotapes at home.	Rectal pain thresholds, rectal smooth muscle tone, and autonomic functioning were unaffected by hypnosis. Somatization and psychological distress showed large decreases. Hypnosis improved IBS symptoms through reductions in psychological distress and somatization.