Jump up ^ Does a genetic programming of the brain occur during paradoxical sleep (1978) by M Jouvet in editors; Buser, Pierre A.; Rougeul-Buser, Arlette (1978). Cerebral correlates of conscious experience : proceedings of an international symposium on cerebral correlates of conscious experience, held in Senanque Abbey, France, on 2-8 august 1977. New York: North-Holland. ISBN 978-0-7204-0659-7.

A trancelike state resembling sleep, usually induced by a therapist by focusing a subject's attention, that heightens the subject's receptivity to suggestion. The uses of hypnosis in medicine and psychology include recovering repressed memories, modifying or eliminating undesirable behavior (such as smoking), and treating certain chronic disorders, such as anxiety.

The U.S. Department of Health & Human Services recognizes the healing power of hypnosis and its proven effectiveness for anxiety, pain control, smoking cessation, headaches and more. Hypnosis may be safe and complementary way to augment medical attention you are receiving for a chronic illness or pain, or a way to resolve an addiction or phobia that you are otherwise unable to control. Hypnosis does not work on every person. When scientists began studying hypnosis in earnest, a report published by Stanford University titled “The Stanford Hypnotic Susceptibility Scale” demonstrated that different brains respond to hypnosis in varying degrees, and a very few do not respond at all. Working with a trained psychologist, you’ll soon determine whether you are a good candidate for the healing benefits of hypnotherapy.
While amnesia may occur in very rare cases, people generally remember everything that transpired while they were hypnotized. However, hypnosis can have a significant effect on memory. Posthypnotic amnesia can lead an individual to forget certain things that occurred before or during hypnosis. However, this effect is generally limited and temporary.
Although most practitioners receive their training in hypnotherapy or relaxation as a part of their academic training, the American Society of Clinical Hypnosis and the Society for Clinical and Experimental Hypnosis maintain training programs as well as a registry of practitioners (see previous box). Training in teaching relaxation techniques is provided through various routes from self-teaching and apprenticeships to a number of short courses. Many yoga centers also teach relaxation and offer courses to train yoga teachers.​teachers.
But how does the suppression mechanism decide what to suppress? In this study, movie content but not movie context was influenced by PHA. Memories involve the “what,” “how,” “when” and “where” of an event interwoven together, such that distinctions between content and context may be blurred (for example, “Was the movie shot with a hand-held camera?”). To make such fine discriminations, the brain’s suppressor module presumably needs to process information at a sufficiently high level. Yet this module needs to act quickly, preconsciously suppressing activation of the information before it even enters awareness. Brain imaging technologies with superior temporal resolution to fMRI, such as magnetoencephalography (MEG), might help to resolve this seeming paradox of sophisticated, yet rapid, operations.
In order for a hypnotherapist to convey positive suggestions for change, the patient must be in a receptive state. The state is called trance and the method of achieving a trance is through induction. Induction techniques are many and varied and involve the therapist offering suggestions that the patient follows. The formerly common "your eyes are getting heavy" suggestion may still exist, but other more reliable and acceptable (by the patient) forms of induction have come to the forefront. The artful hypnotherapist is always aware of the present condition of the patient and uses this information to lead him/her down the path of induction. In its lighter stages, trance can be noted by the relaxation of muscles. At this point, hands can levitate when given the suggestion, and paresthesia, a feeling of numbness, can be induced. In a medium trance, a patient can be led to experience partial or complete amnesia , or failure to recall events of the induction after the fact. A deep trance opens the patient to powerful auditory, visual, or kinesthetic experiences. The phenomenon of time distortion is experienced most profoundly at this level. Patients may believe they have been away briefly, and may react with disbelief when told they were away much longer. Although some work can be done in lighter states of trance, the best circumstance for implementing change is when the patient reaches a deep trance state. At this level, the patient is focused inwardly and is more receptive to positive suggestions for change. This is also the point at which the therapist can invoke posthypnotic suggestions, or instructions given to the patient so he/she will perform some act or experience some particular sensation following awakening from the trance. For example, these suggestions, if accepted by the patient, can be formed to make foods taste bad, cigarettes taste bad, delay impulses, curb hunger, or eliminate pain. However, it should be noted that posthypnotic suggestions given to a person, which run counter to the person's value system or are not something they are likely to do under ordinary circumstances, will not be accepted and therefore not implemented.
It is used for a wide variety of applications, and studies into its efficacy are often of poor quality[2] which makes it difficult to determine efficacy. Several recent meta-analyses and systematic reviews of the literature on various conditions have concluded that the efficacy of hypnotherapy is "not verified",[3] that there is no evidence[4][5] or insufficient evidence[6][7] for efficacy.