A narrative review highlights the lack of methodological elements of hypnosis therapy research ranging from case studies to randomized trials.
A recent narrative review conducted in France shows that there is a lack in key methodological elements within current research on the efficacy of hypnosis for relieving insomnia. This review revealed that there are insufficient supporting evidence for hypnosis being a treatment for this condition based on specific aspects such as population characteristics, study design, primary endpoints, interventions, and the hypnosis techniques used.1
Of the total articles searched initially (n = 208) and the articles selected (n = 55), only 25 articles were used for the final review. The studies in the final review included case studies (n = 10), randomized controlled trials (n = 11), and pre and post intervention studies (n = 4).
Lead author Sarah L. Mamoune, PhD, lecturer, University of Rennes, CHU Rennes, Department of General Practice, F-35000 Rennes, France, and colleagues wrote, “We propose future study designs to evaluate the efficacy of hypnosis to manage insomnia apply the IDEAL framework, which outlines specific research steps to evaluate non-pharmacological and other complex therapies.”1 For context, Mamoune et al used literature from PubMed, Psycinfo, BASE and Cochrane databases, and Google scholar, that focused on treating insomnia with hypnosis.
All of the studies selected were heterogeneous in terms of their design, intervention, control and comparators along with the definitions of hypnosis. Also observed from the studies was a lack of detailed descriptions for types of hypnosis techniques. There were no double-blinded studies that came up in the search and the majority of the studies had non-quantifiable criteria for the measurements, as well as some numbers from the sample revealed to be too small for significance.
“The review found a diverse range of hypnosis techniques were used to treat insomnia with most hypnosis protocols combining several techniques. Some hypnosis protocols used suggestions of relaxation warmth or heaviness or sleep techniques of visualizing a pleasant place, focalization techniques, or behavioral techniques or dissociative techniques. Others used an open-eye alert technique, or even age regressions. Some authors studied their own technique while others used those from previous studies (1960–1990),” Mamoune et al noted.1
The search consisted of studies that had been published between 1963 and 2018, from over 13 countries, along with nearly half of the articles (n =12) published before 2000. Seven studies were published in the United States, 3 studies were from Australia and another 3 were from the United Kingdom. Participants in the studies included students, elderly, and healthy people, or patients with cancer, anxiety or depression.
Overall, a majority of the studies demonstrated hypnosis having a positive effect on insomnia. There were two studies that showed better sleep had been achieved through hypnosis group therapy in comparison with pharmaceutical therapies. Having a replacement of hypnosis, instead of hypnotics, combined with psychotherapy2 or medication discontinued was attainable with hypnosis.
The study investigators experienced limitations with obtaining the articles for the review because of the time period of the publications. Therefore, the small number of results included in the review suggests the studies should be interpreted with caution. Also, the articles that were included in the review had only “hypnosis” as the term for dining the therapy even though there are other definitions for describing the technique of the therapy. Hence, there might be a biased on the articles from the database and the interpretations of the findings.
Future studies need to have a larger sample size which includes searching databases based on clearer and broader search terms to define hypnosis therapy for insomnia. Mamoune and colleagues noted, “It would be interesting to assess the effect of hypnosis on sleep waves among participants with insomnia rather than healthy participants.”1 Furthermore, future research should investigate hypnotherapy facilitating benzodiazepine discontinuation for people with insomnia as they could measure hypnosis efficacy on the dose reduction.