We conducted a systematic review of randomized control trials examining the efficacy of self- hypnosis as a clinical treatment. Searching for ‘self-hypnosis’, ‘self-hypnotic’, ‘autosuggestion’, and ‘autohypnosis’ returned 576 studies, of which 22 met the definition of being an RCT. Self-hypnosis has been reported to be efficacious in studies of pain, childbirth, paediatric applications, stress and anxiety. Methodological differences among studies are discussed. Self-hypnosis is most likely to be effective when taught as an independent self-directed skill and when it involves at least three practice sessions before participation in the trial. Experience of hetero-hypnosis does not seem to be essential in producing an effect for self-hypnosis. Studies reporting no effect typically involved participants listening to audio recordings of hetero-hypnosis only. Meta- analysis revealed a medium-to-large effect size for self-hypnosis in clinical treatment
