Hypnosis: What is it, and does it work?

A recent review published in the journal Neuroscience and Biobehavioral Reviews has defined hypnosis as a kind of top-down regulation of conscious awareness, a process in which “mental representations […] override physiology, perception, and behavior.”

As the authors explain, hypnosis involves two main elements: induction and suggestions. Hypnotic induction is the first suggestion delivered during the process of hypnosis, though what it should consist of is still a matter of debate.

Suggestions are typically expressed as implications that elicit seemingly involuntary responses from the participants, who do not believe they have much, or any, control (or agency) over the situation.

Some people are also more “suggestible” than others, and researchers have found that highly suggestible people are likelier to have a reduced sense of agency while under hypnosis.

Hypnotic suggestibility has been defined as “the ability to experience suggested alterations in physiology, sensations, emotions, thoughts, or behaviour.”

Neuroimaging techniques have shown that highly suggestible people exhibit higher activity levels in the prefrontal cortex, anterior cingulate cortex, and parietal networks of the brain during different phases of hypnosis.

These are areas of the brain involved in a range of complex functions, including memory and perception, processing emotions, and task learning. However, the specific brain mechanisms involved in hypnosis are still unclear, though scientists are beginning to piece together the neurocognitive profile of this process.

Hypnosis and cognition

Many studies link hypnosis specifically to cognitive processes and describe it as “a phenomenon involving attentive receptive concentration.” Some evidence points to the role of hypnosis in controlling selective attention.

The relationship between hypnosis and states of attention is reinforced by the results of past experiments, in which hypnotic suggestion was used to alter different kinds of perception.

For instance, suggestion has been used to induce agnosia, which is a state wherein the brain can perceive but is unable to recognize various external stimuli. Other experiments have employed suggestions to manipulate visuospatial processing, which is the ability of the brain to identify objects in space, and to recognize shapes.

Such effects have often made hypnosis a showbiz attraction, and, when treated as a magician’s trick, it elicits laughter and thrilled gasps. However, the practice of hypnosis has occasionally attracted a different kind of attention, when the stunts of amateur “hypnotists” have appeared to have tragic outcomes.

One person at the receiving end of one such questionable experiment described his mishaps and sense of anxiety in the aftermath.

“I was in this trance. I was told I wouldn’t be able to find my [hotel] room because all the room numbers would be changed to Chinese. I was lost for about 20 to 25 minutes walking around. I was seeing the Chinese lettering, the weird lines and all.”

Another fraught use of hypnosis is that of hypnotic regression. “Therapeutic regression,” which is a method that claims to uncover a person’s repressed memories – often of early abuse and trauma – has sometimes been used in hypnoanalysis, which is a form of psychoanalysis integrating hypnosis techniques.

Some even claim that hypnosis can help to achieve past life regression, unearthing memories from previous lives.

Existing research suggests that hypnotic suggestion can be effective in inducing false memories and convincing individuals of the truthfulness of these fictitious recollections. Such findings throw a negative light on claims of past regression and on the memories thus regained.

However, there are also studies that bring evidence in favor of the claim that hypnosis can improve memory, yet the level of improvement may be dependent on individual expectations.

The potential held by hypnosis for modifying perception is also what makes it particularly fitting as a complementary medicine approach.

Hypnotherapy is currently used, both in the United States and in Europe, to relieve several medical conditions and to help people let go of negative habits that can have a serious impact on their health.

Some cases in which hypnotherapy has been found useful include:

• Irritable bowel syndrome (IBS). Studies have suggested that hypnosis can relieve IBS symptoms in the short-term, though long-term effectiveness has not yet been conclusively tested.
• Insomnia and sleep disorders. Hypnosis can help to manage insomnia, nightmares, and sleep terrors (which tend to affect children between the ages of 7 and 12), as well as some more unusual sleep disorders, such as sleepwalking. Relaxation and self-control suggestions are used to address these conditions.
• Migraine. Some research suggests that hypnosis can be effective in treating migraines and tension headaches, and it might be a desirable alternative treatment thanks to the lack of side effects.
• Clinical pain control. Hypnosis can have analgesic effects in the case of acute clinical pain, which usually means pain resulting from surgical procedures. Some studies also indicate that hypnosis may help women to manage childbirth pain, though supporting evidence is mixed.
• Quitting smoking. The National Center for Complementary and Integrative Health detail studies suggesting that hypnotherapy may help people who want to give up smoking, especially if paired with other means of treatment. But in this case, too, supporting evidence is mixed.

Home uses of hypnotherapy techniques

Increasingly, self-hypnosis and techniques of hypnotic suggestion have picked up steam as “life hacks.” Hypnotherapists and media outlets often list self-hypnosis techniques as a shortcut for achieving relaxation and boosting self-confidence.

Researchers suggest that for these simple techniques to be effective, high levels of suggestibility are unnecessary, and sometimes they advise putting them into practice as a way of supplementing specialist therapies at home.

Some surprising avenues wherein hypnotic suggestion has been used are children’s books. One book, conceived by a writer with extensive knowledge of psychology, employs suggestion techniques to get young children to fall asleep without the extra fuss.

Various links between hypnosis and meditation techniques are also drawn by some researchers. Certain studies suggest that meditation and hypnosis are closely related, as they both play a role in mind-body regulation.

However, other researchers claim that hypnosis and meditation are entirely separate processes, as they rely on distinct mechanisms. Hypnosis, they argue, is essentially a process through which subjects “trick” their own perception, whereas meditation is a means of enhancing, rather than deceiving, awareness.

Despite the fact that the practice of hypnosis has been around for more than 200 years, many of its mechanisms remain mysterious. Its effects may appear to border on the supernatural, yet the brain – as is often the case – holds the key. There may still be some way to go, however, until we fully understand this intriguing instrument called “hypnosis.”