Look into my eyes…

Therapeutic use of hypnosis is perhaps most commonly associated with the archetypal psychoanalyst, using it to unlock memories and associations that might be inaccessible when people are fully conscious. This is one possible therapeutic use, but there are other areas where hypnosis is being trialled.

A recent Swiss paper by Cordi, Schlarb and Rasch has found that listening to an audio recording with hypnotic suggestions to sleep deeper led to people spending more of their nap time in slow-wave sleep, and a significant reduction in their time spent awake. This is a  potentially exciting finding because slow-wave sleep seems to be very important in the body’s repair processes, as well as brain function.  If people can be induced to spend more time in slow-wave sleep, following the experimenters’ logic, then it might improve their physical and mental health and well-being. This is potentially especially pertinent for healthy aging, as people tend to have less slow-wave sleep as they age, so a non drug-based intervention that increases amounts of slow-wave sleep could increase health and memory consolidation in an aging population. This could potentially mitigate the effects of dementias in people who were suggestible enough to be hypnotised.

It is worth noting that the increased slow-wave sleep was only observed in highly suggestible people, and in fact low-suggestible people’s slow-wave sleep significantly decreased in its amount. When people received suggestions to sleep shallower, there was no clear impact on their slow-wave sleep in either group of people. People’s suggestibility was measured using the Harvard Group Scale of Hypnotic Susceptibility.

An interesting part of this finding is that not only is hypnosis being used to communicate with non-conscious parts of the mind, but that the communication appears to be having a measurable physiological effect on sleep architecture – a process which occurs unconsciously. Words received and interpreted by higher cortical areas of the brain are presumably percolating down to areas concerned with deeper physiological functions of sleep, and actually changing the structure of the sleep people are having. This is perhaps even more striking than the apparent power of hypnosis to affect processes that take place when people are not asleep, such as heart rate, pain perception and sporting prowess.

A study in Cell recently demonstrated that if you measure someone’s brain waves, then synchronise the playing of pink-noise to them on the up-stroke of their slow wave sleep oscillations, not only are the slow-wave oscillations seemingly reinforced, but also the participants’ memory functions improved in subsequent tests. This might have implications beyond sleep problems in the realm of memory research. However, to do this more widely, one would need people to be connected to EEGs while they slept, limiting the wider applicability of the intervention, at least until more portable EEG devices are developed. If hypnosis-based interventions can be helpful in the reorganisation of people’s sleep architecture, it seems that further research would be beneficial.  This could look at the possibility of using hypnosis with different groups, and see if there are unanticipated side-effects of the intervention. The intervention itself seems inobtrusive, after the somewhat lengthy process of screening people for their susceptibility.

Storage of people’s susceptibility status (and by extension the record of their having been given hypnosis-based therapy) would probably need to be confidential: perhaps knowledge of who was susceptible might be of use to people or forces that might want to exploit that susceptibility. In a future where NHS records might be more widely shared, this and related confidentiality issues could be something worthy of deeper consideration.


  • How would people feel about an intervention being delivered beyond their conscious awareness or direct control?
  • Does this type of intervention have similar ethical dilemmas to pharmacological interventions?
  • Might therapists have a role in the development of bespoke hypnosis recordings for people’s specific needs?
  • What other concerns might hypnosis be capable of affecting?
  • What might the long-term effects of repeated hypnosis for sleep architecture alteration be?
  • Does the onset of dementia affect people’s susceptibility to hypnosis?


Photo – “Punk Chicken” – Copyright Charlie Tyack