Induction of a state of consciousness characterized by loss of the power of voluntary action; a temporary state of reduced peripheral awareness.

Hypnosis or hypnotism has been practiced since ancient times yet remains difficult to define accurately and completely. Although the word hypnosis comes from the Greek word hypnos, for sleep, hypnosis is actually a state of intense concentration induced to certain degrees of consciousness. Light hypnosis is an induced state under which the subject becomes sleepy and follows simple directions. Deep hypnosis, on the other hand, is an induced state in which the subject experiences dulling of sensory perception, similar to that of anesthesia. Under deep hypnosis, subjects can move about, open their eyes, and sometimes can even undergo medical procedures without anesthesia.

Hypnosis, or hypnotic trance, is done through a process of hypnotic induction on a willing subject. Classical hypnotic induction involves a series of steps:

It is estimated that about 70% of all people can be hypnotized to some level. Among these, an estimated 30% are in the low range, 60% in the middle, and 10% are highly hypnotizable using classical hypnotic induction. Within the scientific community, the claim that a person can be hypnotized against his or her will is controversial. Many scientists feel that an unwilling subject would be difficult to hypnotize, and most scientists raise ethical questions about any attempts to do so.

Although hypnotic responsiveness has been studied mainly based on phenomenological data, a genetic basis for hypnosis has not been explored extensively. However, with the availability of advanced neuroimaging, researchers have studied attention and suggest that it is a psychological construct that could be considered an organ system, and involving the part of the brain anatomy that governs other perceptual and cognitive functions. Three component attentional systems with differen neural networks have been identified, including orienting, alerting, and executive control. It is believed that hypnosis, as a form of deep concentration or focused attention, may have a genetic basis by which to explain why certain people can be hypnotized successfully and other people cannot. Studies of attention, neural or “attentional” networks, and hypnosis are ongoing but without reaching consensus to date.

While in an hypnotic trance, some subjects are able to recall forgotten experiences. This can be useful in treating amnesia or milder forms of memory loss. Interestingly, many subjects do not recall anything that happened while they were in the hypnotic trance; the hypnotist may direct the person to perform some act or engage in a specific behavior after the trance state has ended. This is termed post-hypnotic trance or post-hyp-notic suggestion, and only a small percentage of people who are able to be hypnotized will respond successfully. The post-hypnotic suggestion only works for behaviors that the subject is willing and able to perform; an unscrupulous hypnotist could not enlist an unwilling subject in self-deprecating, dangerous, or criminal activities. Ending the trance is usually accomplished using a preset signal determined by the hypnotist. On occasion, subjects may wake from the trance without the signal being given. However, it is unusual for a hypnotist to have difficulty ending the induced trance.

Some people are able to hypnotize themselves in a process called autohypnosis or self-hypnosis. Self-hypnosis or hypnotherapy is a way to reduce stress, induce relaxation, and to open the mind to positive thought processes. It is sometimes able to reprogram the way people think. The techniques involve exercises designed to bring about deep relaxation; they are not unlike meditation techniques, applying soothing sounds, music, or repeated affirmations or self-suggestion to help induce a hypnotic trance and implant positive ideas. Self-hypnosis resources are available, including tapes, CDs, and MP3s. The processes involved are simple but should be discussed with a physician or psychotherapist and fully understood before attempting to self-hypnotize. The person should want to be hypnotized, not be frightened, and avoid over-analyzing the processes. Subjects are advised to understand what they are hoping to accomplish, and which ideas they would like to implant in the subconscious, before inducing self-hypnosis. Self-hypnosis has been used successfully to relieve stress, reduce additive habits, and reduce nervousness before any event that may be especially challenging, such as public speaking.


A self-induced state of conscious; self-hypnosis.
The consistent inability to control urination.
Hypnotic trance—
An altered state of consciousness induced through hypnosis.
Post-hypnotic suggestion—
A suggestion made to a hypnotized person that specifies an action to be performed upon awakening from hypnotic trance and receiving a cue.

Patients who are responsive to being hypnotized must, first of all, be willing participants in the hypnosis process. One psychiatrist, Dr. Herbert Spiegel (1914– 2009), developed the Hypnotic Induction Profile (HIP) to determine whether an individual is a good prospect for hypnosis. Spiegel suggested that when a possible subject rolls his or her eyes back into the head revealing a great deal of white on the eyeball, that person is likely to be hypnotized successfully. Other qualities in the profile include a trusting personality, preference for emotional rather than rational thinking, high empathy for others, and an intense capacity for concentration.

Other researchers have theorized that creating a setting where the subject is more likely to believe that hypnosis will work is a key to successful hypnosis. These scientists contend that the situation, combined with the subject's motivation, has greater influence than any personality trait or physical characteristic.

Most hypnotherapists are physicians, registered nurses, licensed clinical social workers or counselors. A number of professional organizations offer training and advanced training in hypnosis. Among these are the American Society of Clinical Hypnosis, the American Board of Medical Hypnosis, the American Board of Psychological Hypnosis, the American Board of Hypnosis in Dentistry and the American Hypnosis Board for Clinical Social Work. The American Psychiatric Association, the American Psychological Association, and the American Dental Association have all endorsed the hypnotherapy technique. Hypnotherapy has been used in the clinical setting to treat chronic stress, tinnitus, sexual dysfunction, eating disorders, digestive disorders, smoking and other addictions, enuresis and thumb-sucking. A diagnosis is always needed before someone is treated with hypnotherapy.



Hammond, D. Corydon. Handbook of Hypnotic Suggestions and Metaphors. An American Society of Clinical Hypnosis Book. New York: W.W. Norton & Company, 1990.

Rossi, E. L. A Discourse with Our Genes: The Psychosocial and Cultural Genomics of Therapeutic Hypnosis and Psychotherapy. Torino, Italy: Editris, 2005.

Yapko, Michael D. Mindfulness and Hypnosis: The Power of Suggestion to Transform Experience. New York: W.W. Norton & Company, 2011.


Elkins, G., A. Johnson, and W. Fisher. “Cognitive hypnotherapy for pain management.” American Journal of Clinical Hypnosis 54 (April 2012): 294–319.

Rax, A., J. Fan, and M.I. Posner. “Neuroimaging and genetic associations of attentional and hypnotic processes.” Journal of Physiology-Paris 99 (June 2006): 483– 491.


The American Association of Professional Hypnotherapists. About Hypnotherapy. (accessed July 29, 2015). http://www.aaph.org .


American Society of Clinical Hypnosis, 2200 East Devon Avenue, Suite 291, Des Plaines, IL, 60018, (847) 297–3317.

Society for Clinical and Experimental Hypnosis, 3905 Vincennes Road, Suite 304, Indianapolis, IN, 46268, (800) 214–1738.