Background: Hypnotherapy is widely promoted as a method for aiding smoking cessation. It is proposed to act on underlying impulses to weaken the desire to smoke or strengthen the will to stop.
Objectives: To evaluate the efficacy of hypnotherapy for smoking cessation.
Search strategy: We searched the Cochrane Tobacco Addiction Group Specialized Register and the databases MEDLINE, EMBASE, AMED, SCI, SSCI using the terms smoking cessation and hypnotherapy or hypnosis. Date of most recent searches July 2010. There were no language restrictions.
Selection criteria: We considered randomized controlled trials of hypnotherapy which reported smoking cessation rates at least six months after the beginning of treatment.
Data collection and analysis: Three authors independently extracted data on participant characteristics, the type and duration of the hypnotherapy, the nature of the control group, smoking status, method of randomization, and completeness of follow up. They also independently assessed the quality of the included studies.The main outcome measure was abstinence from smoking after at least six months follow up. We used the most rigorous definition of abstinence in each trial, and biochemically validated rates where available. Those lost to follow up were considered to be smoking. We summarised effects as risk ratios (RR). Where possible, we performed meta-analysis using a fixed-effect model. We also noted any adverse events reported.
Main results: Eleven studies compared hypnotherapy with 18 different control interventions. There was significant heterogeneity between the results of the individual studies, with conflicting results for the effectiveness of hypnotherapy compared to no treatment, or to advice, or psychological treatment. We did not attempt to calculate pooled risk ratios for the overall effect of hypnotherapy. There was no evidence of a greater effect of hypnotherapy when compared to rapid smoking or psychological treatment. Direct comparisons of hypnotherapy with cessation treatments considered to be effective had confidence intervals that were too wide to infer equivalence.
Authors' conclusions: We have not shown that hypnotherapy has a greater effect on six-month quit rates than other interventions or no treatment. There is not enough evidence to show whether hypnotherapy could be as effective as counselling treatment. The effects of hypnotherapy on smoking cessation claimed by uncontrolled studies were not confirmed by analysis of randomized controlled trials.