Hypnosis to Manage Distress Related to Medical Procedures: a Meta-analysis.

This meta-analysis evaluates the effect of hypnosis in reducing emotional distress associated with medical procedures. PsycINFO and PubMed were searched from their inception through February 2008. Randomized controlled trials of hypnosis interventions, administered in the context of clinical medical procedures, with a distress outcome, were included in the meta-analysis (26 of 61 papers initially reviewed). Information on sample size, study methodology, participant age and outcomes were abstracted independently by 2 authors using a standardized form. Disagreements were resolved by consensus. Effects from the 26 trials were based on 2342 participants. Results indicated an overall large effect size (ES) of 0.88 (95% CI = 0.57-1.19) in favour of hypnosis. Effect sizes differed significantly (p < 0.01) according to age (children benefitted to a greater extent than adults) and method of hypnosis delivery, but did not differ based on the control condition used (standard care vs. attention control).