In the brain, this state looks stranger still. A landmark study in the prestigious journal Science in the late 1990s, led by Pierre Rainville of the University of Montreal, described a study in which hypnotized people briefly placed their left hand in either painfully hot water, heated to 116 degrees Fahrenheit, or room-temperature water. Some of them had been told that they would be experiencing pain, but that they wouldn’t be very bothered by it — if, on a scale of one to ten, the hurt would normally register at an eight, they’d feel it as if it were a four. As all the participants placed their hands in the 116-degree water, their brains were scanned. The results were clear: Those who had been told that the pain would be less intense showed less activity in their brains — specifically, in the anterior cingulate cortex, which is associated with pain processing.

Some therapists use hypnosis to recover possibly repressed memories they believe are linked to the person's mental disorder. However, the quality and reliability of information recalled by the patient under hypnosis is not always reliable. Additionally, hypnosis can pose a risk of creating false memories -- usually as a result of unintended suggestions or the asking of leading questions by the therapist. For these reasons, hypnosis is no longer considered a common or mainstream part of most forms of psychotherapy. Also, the use of hypnosis for certain mental disorders in which patients may be highly susceptible to suggestion, such as dissociative disorders, remains especially controversial.
Trance is commonplace. People fall into traces many times without even being aware that it happened. Examples of this are: reaching the destination of a morning commute, but not recalling the passing of familiar landmarks; daydreaming while sitting in a college classroom; or that anxiety-free state achieved just before going to sleep. The difference between these altered states and clinically used hypnotherapy is that a professionally trained person is involved in helping the patient achieve the trance, which can be done in many ways.

The analysis method of hypnotherapy, sometimes referred to as regression therapy, is more exploratory and related to uncovering the root of an issue, disorder or symptom. A hypnotherapist will hypnotize a patient by putting them into a relaxed state and exploring a past event in their life in order to explore the person’s subconscious and unconscious memory.

Hypnotism has also been used in forensics, sports, education, physical therapy, and rehabilitation.[78] Hypnotism has also been employed by artists for creative purposes, most notably the surrealist circle of André Breton who employed hypnosis, automatic writing, and sketches for creative purposes. Hypnotic methods have been used to re-experience drug states[79] and mystical experiences.[80][81] Self-hypnosis is popularly used to quit smoking, alleviate stress and anxiety, promote weight loss, and induce sleep hypnosis. Stage hypnosis can persuade people to perform unusual public feats.[82]

Finally, the neural underpinnings of PHA will be even clearer when we incorporate its most important aspect in imaging studies—the dissociation between implicit and explicit memory. In PHA (and in functional amnesia) the person is unable to explicitly recall certain information, yet we see evidence of this material on implicit measures. For instance, a participant given PHA may fail to recall the word “doctor,” learned earlier, but will have no trouble completing the word fragment “d _ _ t _ r”. Mendelsohn et al. did not assess implicit memory. Rather, they tested recognition, which in a sense confounds explicit and implicit memory. We’d like to compare brain scans of a PHA group trying to explicitly recall the movie (they should show reduced activation, as above) with brain scans of the same group completing an implicit memory measure of the movie (they should show normal activation). This would be tricky to do—implicit measures of complex material such as movies and autobiographical memories are hard to find or construct. But it would contribute to a more complete neural picture of the processes involved in these fascinating forms of forgetting. 
Dave Elman was a master hypnotherapist, teaching physicians, dentists and psychologists back in the 1950s how to do what they should already have been taught in their training. This book is full of stories, examples and dialogues with clients that demonstrate his ability to work successfully with a stunning array of people. It is truly amazing that it has taken over 50 years since his work in order for hypnosis to begin emerging as the tool for personal transformation that it is. Although the history of hypnosis is much older that that, it has long suffered the indignity of scorn by those who don't understand it, fear it or simply believe it can't really work.
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.
We believe that hypnosis will be optimally effective when the patient is highly motivated to overcome a problem and when the hypnotherapist is well trained in both hypnosis and in general considerations relating to the treatment of the particular problem. Some individuals seem to have higher native hypnotic talent and capacity that may allow them to benefit more readily from hypnosis.

Pierre Janet (1859–1947) reported studies on a hypnotic subject in 1882. Charcot subsequently appointed him director of the psychological laboratory at the Salpêtrière in 1889, after Janet had completed his PhD, which dealt with psychological automatism. In 1898, Janet was appointed psychology lecturer at the Sorbonne, and in 1902 he became chair of experimental and comparative psychology at the Collège de France.[60] Janet reconciled elements of his views with those of Bernheim and his followers, developing his own sophisticated hypnotic psychotherapy based upon the concept of psychological dissociation, which, at the turn of the century, rivalled Freud's attempt to provide a more comprehensive theory of psychotherapy.
Meditation practice focuses on stilling or emptying the mind. Typically, meditators concentrate on their breath or a sound (mantra) they repeat to themselves. They may, alternatively, attempt to reach a state of “detached observation,” in which they are aware of their environment but do not become involved in thinking about it. In meditation, the body remains alert and in an upright position. In addition to formal sitting meditation, patients can be taught mindfulness meditation, which involves bringing a sense of awareness and focus to their involvement in everyday activities.
Hypnotherapy expert, Dr Peter Marshall, former Principal of the London School of Hypnotherapy and Psychotherapy Ltd. and author of A Handbook of Hypnotherapy, devised the Trance Theory of Mental Illness, which provides that people suffering from depression, or certain other kinds of neurosis, are already living in a trance and so the hypnotherapist does not need to induce them, but rather to make them understand this and help lead them out of it.[24]