Hypnotherapy is the one on this shelf with trials behind it

What a session is

You stay awake. A practitioner talks you into a state of narrowed, absorbed attention, the same state you are in when a film stops feeling like a screen, and then makes suggestions inside it: that the pain is further away, that the gut is calm, that the cigarette is uninteresting. Gut-directed hypnotherapy, the version with the best clinical support, is usually six to twelve sessions with recordings to use at home.

You cannot be made to do anything you would refuse awake, and you will remember it. Both of those beliefs come from stage hypnosis, which is a performance with volunteers selected for suggestibility and a strong social pressure to play along.

Mesmer, and the commission that took him apart

The practice descends from Franz Mesmer, who in the 1770s explained his results by an invisible fluid he called animal magnetism. In 1784 Louis XVI appointed a royal commission to test the claim. Its members included Benjamin Franklin and Antoine Lavoisier, and their method was to separate the fluid from the belief in it: subjects were blindfolded and told they were being magnetised when they were not, and not told when they were.

People reacted to the trees they believed had been magnetised and not to the ones that had been. The commission reported that the effects were real and that the cause was imagination, not any fluid. That report is one of the earliest blinded controlled experiments anyone ran, and its finding has held for two and a half centuries: something happens, and it is happening in the person rather than passing into them.

James Braid renamed the practice hypnotism in the 1840s and dropped the fluid entirely, which is roughly where clinical hypnosis has stayed. It is the rare case of a nineteenth-century wellness practice that survived by giving up its mechanism.

Where the evidence is strongest

Irritable bowel syndrome is the clear case. NICE's guideline on IBS in adults says referral for psychological interventions, naming cognitive behavioural therapy, hypnotherapy and psychological therapy, should be considered for people whose symptoms have not responded to drug treatment after 12 months. That is a national guideline body recommending it inside the NHS, not a wellness site making a claim.

Two caveats sit next to that. The Cochrane review of hypnotherapy for IBS (doi.org/10.1002/14651858.CD005110.pub2) found the quality of the trials inadequate to draw a conclusion, so the guideline rests on a body of small studies rather than a single decisive one. And blinding a talking therapy is close to impossible, which caps how strong the evidence can ever get.

Procedural pain and anxiety are the other area with reasonable support: hypnosis before and during unpleasant medical procedures reduces reported pain and distress in a fair number of trials.

Where it thins out

Smoking is the useful test, because it has been studied for decades and everyone wants it to work. The Cochrane review of hypnotherapy for smoking cessation (doi.org/10.1002/14651858.CD001008.pub3) pooled 14 studies and about 1,900 people and concluded there was insufficient evidence to say hypnotherapy beats other behavioural support or quitting unaided, adding that if a benefit exists it is small at most.

Weight loss, phobias, depression, fertility, past-life regression: the further you get from a symptom that responds to attention and expectation, the weaker the evidence, and past-life regression is not a treatment for anything.

This is the shape of a real therapy with a narrow indication being sold as a general one, which is different from a practice with no evidence at all being sold as a cure. Both need calling out, and they need calling out differently.

The part that can do harm

Not the trance. The memory.

Hypnosis reliably raises a person's confidence in what they recall without raising its accuracy, and it increases pseudomemory, details that feel remembered and never happened. A memory recovered under hypnosis arrives with unusual certainty attached, which is exactly what makes it dangerous.

That is why courts across many jurisdictions restrict or exclude hypnotically refreshed testimony, and it is the mechanism behind the recovered-memory cases of the 1980s and 1990s that broke apart families on the strength of memories that formed during therapy.

So the rule is narrow and firm: hypnotherapy for a symptom you already have, yes, where the evidence supports it. Hypnotherapy to find out what happened to you, no.

Who is allowed to call themselves a hypnotherapist

In the UK and most of the US, anyone. The title is not protected, the training can be a weekend, and the certificate on the wall may be from an organisation the practitioner joined by paying a fee.

What is regulated is the underlying profession. A clinical psychologist, doctor, nurse or accredited psychotherapist who also uses hypnosis is accountable to a body that can strike them off. That is the qualification to look for, and it is a different question from how impressive the hypnosis training sounds.

Why this piece reads differently from the rest of the shelf

This site is usually explaining that a practice has no demonstrated mechanism. Hypnotherapy is the case where the mechanism is not the problem, because nobody serious claims a fluid any more. Suggestion and focused attention are ordinary psychological phenomena that have been measured for two hundred years.

The problem is scope. A therapy with good support for one condition gets sold for forty, and the person selling it for the fortieth is often sincere. When a practice earns its evidence in a narrow lane, saying so is the same job as saying when a practice has none.

Does hypnotherapy work?

For some things. NICE recommends considering referral for hypnotherapy in irritable bowel syndrome that has not responded to drug treatment after 12 months, and hypnosis has reasonable support for procedural pain and distress. For smoking cessation the Cochrane review found the trials too weak to say whether it helps. Claims beyond a handful of indications outrun the evidence.

Can you be hypnotised against your will?

No. Hypnosis needs cooperation and absorbed attention, and people do not do things under it that they would refuse while fully alert. Stage hypnosis creates the opposite impression by selecting highly suggestible volunteers and putting them under strong social pressure in front of an audience.

Is hypnotherapy safe?

The session itself is low-risk for most people. The real hazard is memory: hypnosis increases confidence in recalled details without increasing their accuracy and can create vivid false memories, which is why many courts restrict hypnotically refreshed testimony. Hypnosis used to recover memories of past events, or of past lives, is the use to avoid.

Is a hypnotherapist medically qualified?

Not necessarily. The title is unprotected in the UK and most of the US, so training can be brief and the certificate may come from a membership organisation rather than a regulator. Look for someone whose underlying profession is regulated, such as a clinical psychologist, doctor or accredited psychotherapist who also uses hypnosis.

How many sessions of hypnotherapy do you need?

Gut-directed hypnotherapy for IBS, the best-supported use, usually runs to six to twelve sessions with recordings to practise at home. An open-ended course with no planned end and no defined target is a sign to ask harder questions about what is being treated.