Hypnotherapy is a type of complementary therapy that uses hypnosis, which is an altered state of consciousness.
Hypnosis is widely promoted as a treatment for various long-term conditions and for breaking certain habits. This is despite the fact there's no strong evidence to support these uses.
However, hypnosis does seem to have an effect, though scientists disagree about how it works. Some experts see it as a relaxation technique that uses the power of suggestion or relies on the placebo effect.
When might it be helpful?
Irritable bowel syndrome
Some research studies have suggested that hypnotherapy may help with the symptoms of irritable bowel syndrome (IBS), such as abdominal pain.
These studies don't provide any strong evidence for its effectiveness, but the National Institute for Health and Care Excellence (NICE) has nevertheless recognised hypnotherapy as a possible treatment for IBS in those who haven't responded to other treatments.
Losing weight and quitting smoking
There's only limited research evidence that hypnotherapy may help some people to lose weight and to quit smoking, so we can't be certain of its benefit.
Read the 2010 Cochrane review on Hypnotherapy for Smoking Cessation and the 2009 Cochrane review on Psychological Interventions for Overweight or Obesity.
Some studies suggest that hypnotherapy can be beneficial for childhood eczema. It may also be useful for treating other minor skin conditions, especially those made worse by stress, if used alongside medicine.
Anxiety, pregnancy and childbirth
Hypnotherapy is widely promoted as a treatment for anxiety, although a systematic review of the effectiveness of hypnosis for the treatment of anxiety found there wasn't enough good evidence to support this.
Overall, the evidence supporting the use of hypnotherapy as a treatment in these situations isn't strong enough to make any recommendations for clinical practice.
No firm conclusions can be made, because the studies are generally only small and of poor quality.
That doesn't mean hypnotherapy won't help you - but if you wish to try it, be aware of the relevant safety and regulation issues, outlined below.
Safety and regulation issues
Hypnotherapy is practised by some doctors, dentists, psychologists and counsellors, but it's also offered by non-professionals with little training. This is because in the UK, hypnotherapists don't have to join any organisation or have any specific training by law.
Make sure you choose a qualified hypnotherapist with a solid healthcare background. Most health professionals who practise hypnotherapy belong to a professional organisation such as the UK Council for Psychotherapy (UKCP) and are regulated by the Complementary and Natural Healthcare Council (CNHC). Search for a CNHC-registered hypnotherapist.
You can also find a hypnotherapist by searching the website of the National Hypnotherapy Society. This organisation has a register accredited by the Professional Standards Authority.
A private hypnotherapy session can cost anywhere between £50 and £90, although costs will vary across the country. It's unlikely you would get hypnotherapy on the NHS, but it depends on the availability in your area.
What to expect
You're fully in control when under hypnosis and don't have to take on the therapist's suggestions if you don't want to. If necessary, you can bring yourself out of the hypnotic state.
Hypnosis doesn't work if you don't want to be hypnotised.
According to Cancer Research UK, most cancer patients say they've had a positive experience with hypnotherapy, although it has made some feel anxious. Read information about hypnotherapy on the Cancer Research UK website.
When you shouldn't use hypnotherapy
If you have any type of mental health problem or serious illness, such as cancer, make sure the hypnotherapist is trained in working with your particular condition.
Similarly, children should not be hypnotised by anyone who isn't trained to work with this age group.