The Cochrane Collaboration, established in 1993, is an international network of people helping healthcare providers, policy makers, patients, their advocates and carers, make well-informed decisions about human health care by preparing, updating and promoting the accessibility of Cochrane Reviews – over 4,000 so far, published online in the Cochrane Library.

They have had a review of the evidence for hypnosis in smoking cessation for some time, but the article was updated in 2010. They conclude that:

"Different types of hypnotherapy are used to try and help people quit smoking. Some methods try to weaken people's desire to smoke, strengthen their will to quit, or help them concentrate on a 'quit programme'. Trials have used different types and amounts of hypnotherapy and compared them with different control conditions, including no treatment, brief advice, or smoking cessation counselling. Although it is possible that hypnotherapy could be as effective as counselling treatment there is not enough good evidence to be certain of this."

In summary, it seems that there aren't enough high-quality studies to be able to say definitively whether hypnosis is superior to any other treatment. At best, we can say that it appears to be equivalent.

Barnes J, Dong CY, McRobbie H, Walker N, Mehta M, Stead LF. Hypnotherapy for smoking cessation. Cochrane Database of Systematic Reviews 2010, Issue 10. Art. No.: CD001008. DOI: 10.1002/14651858.CD001008.pub2

Read the full article here (click on 'full text')