Hypnosis Intervention Effects on Sleep Outcomes: A Systematic Review

Study Objectives: Sleep improvement is a promising target for preventing and modifying many health problems. Hypnosis is considered a cost-effective and safe intervention with reported benefits for multiple health conditions. There is a growing body of research assessing the efficacy of hypnosis for various health conditions in which sleep was targeted as a primary or secondary outcome. This review aimed to investigate the effects of hypnosis interventions on sleep, to describe the hypnotic procedures, and to evaluate potential adverse effects of hypnosis. Methods: We reviewed studies (prior to January 2017) using hypnosis in adults for sleep problems and other conditions comorbid with sleep problems, with at least one sleep outcome measure. Randomized controlled trials and other prospective studies were included. Results: One hundred thirty-nine nonduplicate abstracts were screened, and 24 of the reviewed papers were included for qualitative analysis. Overall, 58.3% of the included studies reported hypnosis benefit on sleep outcomes, with 12.5% reporting mixed results, and 29.2% reporting no hypnosis benefit; when only studies with lower risk of bias were reviewed the patterns were similar. Hypnosis intervention procedures were summarized and incidence of adverse experiences assessed. Conclusions: Hypnosis for sleep problems is a promising treatment that merits further investigation. Available evidence suggests low incidence of adverse events. The current evidence is limited because of few studies assessing populations with sleep complaints, small samples, and low methodological quality of the included studies. Our review points out some beneficial hypnosis effects on sleep but more high-quality studies on this topic are warranted.