Picture an operating theatre in Germany. The patient on the table is fully unconscious under general anaesthesia. Machines breathe for her, and she will remember nothing of the next two hours.
Yet she is wearing headphones.
Through them, a calm voice is telling her that she is safe, that the operation is going well, and that her body knows how to heal. Between the words there is quiet music. As far as she will ever know, she heard none of it.
This was part of a real trial. In 2020, a team of German anaesthetists published the results in the BMJ. They had randomly assigned 385 patients either to these recordings or to silent headphones during their operations. Afterwards, the patients who had been “spoken to” while unconscious needed about a quarter less opioid pain medication in the first day after surgery.
Nobody had hypnotised them in any ordinary sense. They couldn’t have chosen to listen. But something in the anaesthetised brain seems to have been paying attention.
An old idea that was laughed at
The German team weren’t the first to try this. In 1988, British researchers Christine Evans and Philip Richardson played taped positive suggestions to women undergoing hysterectomy under general anaesthesia, while a comparison group heard a blank tape. The women who had heard the suggestions went home from hospital noticeably sooner, and had fewer complications such as fever along the way.
At the time, the result was met with a good deal of scepticism. Later studies were mixed, and the idea that unconscious patients might respond to words stayed on the fringes of medicine. The 2020 trial, larger and more carefully designed, has pushed it firmly back into serious discussion.
It shouldn’t be completely surprising. Anaesthetists have long known that hearing is one of the last senses to fade as anaesthesia deepens, and that the brain goes on processing some sound even when a patient will remember nothing. That’s why many surgical teams are careful about what they say beside an anaesthetised patient. It turns out the reverse may also be true: what’s said can help.
Before surgery: hypnosis versus a sedative
For most people, the hardest part of surgery comes before it: the waiting, the gown, the trolley ride, the mask.
For children, that moment can be terrifying, and it often leaves a mark. After an operation, many children have nightmares, tantrums, bedwetting or new fears for days or weeks.
In 2005, French anaesthetist Sophie Calipel and her colleagues compared two ways of preparing children for minor surgery. Half received midazolam, the standard pre-operative sedative. The other half received hypnosis instead: an anaesthetist talking them into an imaginary story or favourite place as they were wheeled in.
The hypnosis group were noticeably less anxious when the anaesthetic mask was placed over their faces. In the days after surgery, they also had far fewer of those behaviour problems than the children given the sedative. A story did better than a drug.
Adults benefit from preparation too. A few sessions in the weeks before an operation, with a practitioner or a good recording, can give you a reliable way to settle yourself, so that on the day it’s a skill you already have rather than something new to try. For background on how trained clinicians use this, see the article on clinical hypnosis therapy.
During surgery: awake or asleep
How hypnosis is used during an operation depends on whether you’re awake.
If you’re having general anaesthesia, you can’t take part. But as the German trial suggests, recorded suggestions played through headphones may still reduce pain afterwards. A few hospitals now offer this, and it costs almost nothing to ask.
If you’re having local or regional anaesthesia, awake but numb, hypnosis can be used live. A clinician guides your attention away from the sounds, smells and tugging sensations of surgery while the anaesthetic handles the pain. Some hospitals have used this approach, called hypnosedation, for thousands of operations. We cover its history and evidence in our article on hypnosis and anaesthesia.
The same principles are used in the dentist’s chair, where fear is often a bigger problem than pain. See our guide to hypnosis dentistry.
After surgery: healing faster?
The most intriguing findings may come after the operation.
In 2003, a small Harvard study led by psychologist Carol Ginandes followed women having breast reduction surgery. One group received usual care, another received extra supportive attention, and a third received hypnosis sessions before and after surgery, with suggestions focused on comfort and healing.
When surgeons who didn’t know which group each woman was in examined their wounds, the hypnosis group were healing measurably faster, both at one week and at seven weeks.
It was a tiny study, with only 18 women, and it needs repeating on a much larger scale. But it fits a broader pattern. Stress hormones are known to slow wound healing, so anything that genuinely lowers stress after surgery may give the body a little more room to repair itself.
The big picture in one number
So how much does all this add up to?
In 2002, psychologist Guy Montgomery and his colleagues pooled the results of 20 studies of hypnosis with surgical patients, covering more than 1,600 people. They looked at outcomes including:
- pain
- anxiety
- medication use
- physical recovery
- length of hospital stay.
Their headline finding was striking. On average, patients who received hypnosis did better than 89% of patients who didn’t.
That doesn’t mean 89% of people benefit, and it doesn’t mean hypnosis replaces anything. It means that, across a wide range of operations, adding hypnosis to normal care consistently tilted outcomes in patients’ favour. Few psychological techniques in medicine can point to a number like that.
As with any use of hypnosis, the details matter: the kind of surgery, the method, and how responsive each person is. Our overview of does hypnosis work looks at how the evidence differs from one condition to another.
If you’re considering it
The best time to raise hypnosis is when your surgery is first booked, not on the day. It’s worth asking your surgical team:
- Do you offer hypnosis, or recorded suggestions during anaesthesia?
- Can I use my own recording before and after the operation?
- Is my procedure one where awake hypnosis with local anaesthetic is an option?
- Who could I see beforehand to learn self-hypnosis?
Many teams will never have been asked. Some may be curious enough to say yes.
Further reading
- Nowak H, Zech N, Asmussen S, et al. “Effect of therapeutic suggestions during general anaesthesia on postoperative pain and opioid use: multicentre randomised controlled trial.” BMJ. 2020;371:m4284.
- Evans C, Richardson PH. “Improved recovery and reduced postoperative stay after therapeutic suggestions during general anaesthesia.” The Lancet. 1988;332(8609):491–493.
- Calipel S, Lucas-Polomeni MM, Wodey E, Ecoffey C. “Premedication in children: hypnosis versus midazolam.” Paediatric Anaesthesia. 2005;15(4):275–281.
- Ginandes C, Brooks P, Sando W, Jones C, Aker J. “Can medical hypnosis accelerate post-surgical wound healing? Results of a clinical trial.” American Journal of Clinical Hypnosis. 2003;45(4):333–351.
- Montgomery GH, David D, Winkel G, Silverstein JH, Bovbjerg DH. “The effectiveness of adjunctive hypnosis with surgical patients: a meta-analysis.” Anesthesia & Analgesia. 2002;94(6):1639–1645.