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.

Hypnosis can be defined as a procedure during which changes in sensations, perceptions, thoughts, feelings or behaviour are suggested. Hypnosis can be used to amplify whatever it is about therapy that makes it therapeutic. It permits a wide range of choices regarding where and how to intervene in the patient's problems. In this paper, we set out to examine the rationale of using hypnotherapy to manage various types of sleep disorders, and to explore the techniques, strategies and hypnotic scripts employed by various hypnotherapists. We also examine the research data available on the efficacy of hypnosis in the treatment of sleep disorders. Acute and chronic insomnia often respond to relaxation and hypnotherapy approaches, along with sleep hygiene instructions. Hypnotherapy has also helped with nightmares and sleep terrors. There are several reports of successful use of hypnotherapy for parasomnias, specifically for head and body rocking, bedwetting and sleepwalking. Hypnosis is a specialised technique, not a therapy itself, and should be used as an adjunctive intervention within a complete psychological and medical treatment package. Most of the literature is limited to case reports or studies with such a small sample that at times it is very difficult to interpret the results. There is a major placebo effect, so uncontrolled trials are of limited value. It is hard to perform a randomised, double-blind, controlled trial to evaluate hypnotherapy given that cooperation and rapport between patient and therapist is needed to achieve a receptive trance state.
Hypnotherapy is used for nonmedical patients as well as those who wish to overcome bad habits. Hypnotherapy has been shown to help those who suffer from performance anxiety, such as in sports, and speaking in public. In academic applications, it has also been shown to help with learning, participating in the classroom, concentrating, studying, focusing attention span, improving memory, and helping remove mental blocks about particular subjects.
Franz Mesmer (1734–1815) believed that there is a magnetic force or "fluid" called "animal magnetism" within the universe that influences the health of the human body. He experimented with magnets to impact this field in order to produce healing. By around 1774, he had concluded that the same effect could be created by passing the hands in front of the subject's body, later referred to as making "Mesmeric passes". The word "mesmerize", formed from the last name of Franz Mesmer, was intentionally used to separate practitioners of mesmerism from the various "fluid" and "magnetic" theories included within the label "magnetism".
Adverse events resulting from relaxation techniques are uncommon. Rare reports describe basilar or vertebral artery occlusion after yoga postures that put particular strain on the neck. People with poorly controlled cardiovascular disease should avoid progressive muscle relaxation because abdominal tensing can cause the Valsalva response. Patients with a history of psychosis or epilepsy have reportedly had further acute episodes after deep and prolonged meditation.
Hypnosis is not a unitary state and therefore should show different patterns of EEG activity depending upon the task being experienced. In our evaluation of the literature, enhanced theta is observed during hypnosis when there is task performance or concentrative hypnosis, but not when the highly hypnotizable individuals are passively relaxed, somewhat sleepy and/or more diffuse in their attention.[174]
Changes in brain activity have been found in some studies of highly responsive hypnotic subjects. These changes vary depending upon the type of suggestions being given.[168][169] The state of light to medium hypnosis, where the body undergoes physical and mental relaxation, is associated with a pattern mostly of alpha waves[170] However, what these results indicate is unclear. They may indicate that suggestions genuinely produce changes in perception or experience that are not simply a result of imagination. However, in normal circumstances without hypnosis, the brain regions associated with motion detection are activated both when motion is seen and when motion is imagined, without any changes in the subjects' perception or experience.[171] This may therefore indicate that highly suggestible hypnotic subjects are simply activating to a greater extent the areas of the brain used in imagination, without real perceptual changes. It is, however, premature to claim that hypnosis and meditation are mediated by similar brain systems and neural mechanisms.[172]
Yoga practice involves postures, breathing exercises, and meditation aimed at improving mental and physical functioning. Some practitioners understand yoga in terms of traditional Indian medicine, with the postures improving the flow of prana energy around the body. Others see yoga in more conventional terms of muscle stretching and mental relaxation.
Several professional organizations and licensing agencies exist for hypnotherapy practitioners. Examples include the American Society of Clinical Hypnosis (ASCH) and the American Association of Professional Hypnotherapists. To be an ASCH member, practitioners must attend at least 40 hours of workshop training, 20 hours of individual training, and have completed at least two years of clinical practice as a hypnotherapist.
Hypnosis is first and foremost a self-accepted journey away from the reality of the moment. Although the trance state is often referred to as if the patient is asleep, nothing could be further from the truth. The patient is fully awake at all times. The hypnotic subject is simply in a heightened, more receptive state of mind. This fact is proven with inductions called open-eye techniques, where the patient keeps his/her eyes open during the hypnotherapy. Full and deep trance is still achievable.
We also wonder how the suppression mechanism in PHA relates to the vast array of forgetting in the laboratory and in the world? Whereas some forgetting is seen as strategic, effortful and conscious (say, suppression), other forgetting is seen as automatic, effortless and unconscious (say, repression). Having mapped the common features of PHA and functional amnesia, we now need to explore and compare in greater detail their common processes (such as strategy use, motivation, level of awareness).
Around 1900, there were very few preoperative anesthetic drugs available. Patients were naturally apprehensive when facing surgery. One out of four hundred patients would die, not from the surgical procedure, but from the anesthesia. Dr. Henry Munro was one of the first physicians to use hypnotherapy to alleviate patient fears about having surgery. He would get his patients into a hypnotic state and discuss their fears with them, telling them they would feel a lot better following surgery. Ether was the most common anesthetic at that time, and Dr. Munro found that he was able to perform surgery using only about 10% of the usual amount of ether.
So far, so good. For people in the PHA group, brain activation measured by fMRI correlated with the failure to remember. But what if reduced activation is always found in such people regardless of whether they are remembering or forgetting? We can rule this possibility out because people in the PHA group showed reduced activation only when they (unsuccessfully) answered questions about the content of the movie, not when they (successfully) answered questions about the context of the movie. Indeed, for the context questions, they showed the same activation as people in the non-PHA group. Perhaps then, the reduced activation reflects complete forgetting of the information, not just temporary suppression? We can rule this possibility out also because, in a neat reversal, people in the PHA group showed normal activation—just as those in the non-PHA group did—as soon as the suggestion was cancelled.
Take any bright object (e.g. a lancet case) between the thumb and fore and middle fingers of the left hand; hold it from about eight to fifteen inches from the eyes, at such position above the forehead as may be necessary to produce the greatest possible strain upon the eyes and eyelids, and enable the patient to maintain a steady fixed stare at the object.

In most states, the practice of hypnosis is not regulated, so it's important to look for someone who's experienced. Many licensed health care professionals, such as social workers, psychologists, and medical doctors, have been trained in hypnotherapy. People who are not health care professionals can be certified at a number of schools, which may require 60 to more than 200 hours of training. In the United States, certified, experienced practitioners can be found at the National Board for Certified Clinical Hypnotherapists (NBCCH). Although certification with the NBCCH is not a requirement for practicing hypnosis, the NBCCH was formed by hypnotherapists hoping to improve the standards and integrity of the hypnosis profession. Other countries have their own systems of certification.

People have been pondering and arguing over hypnosis for more than 200 years, but science has yet to fully explain how it actually happens. We see what a person does under hypnosis, but it isn't clear why he or she does it. This puzzle is really a small piece in a much bigger puzzle: how the human mind works. It's unlikely that scientists will arrive at a definitive explanation of the mind in the foreseeable future, so it's a good bet hypnosis will remain something of a mystery as well.
Contemporary hypnotism uses a variety of suggestion forms including direct verbal suggestions, "indirect" verbal suggestions such as requests or insinuations, metaphors and other rhetorical figures of speech, and non-verbal suggestion in the form of mental imagery, voice tonality, and physical manipulation. A distinction is commonly made between suggestions delivered "permissively" and those delivered in a more "authoritarian" manner. Harvard hypnotherapist Deirdre Barrett writes that most modern research suggestions are designed to bring about immediate responses, whereas hypnotherapeutic suggestions are usually post-hypnotic ones that are intended to trigger responses affecting behaviour for periods ranging from days to a lifetime in duration. The hypnotherapeutic ones are often repeated in multiple sessions before they achieve peak effectiveness.[39]
It is far easier to describe what hypnosis is not rather than to describe what it is. For example, it is not one person controlling the mind of another. The patient is not unconscious and does not lose control of his or her faculties. People will not do things under hypnosis that they would be unwilling to do otherwise. The person being hypnotized is always in control. The hypnotized person decides how deep the trance will be, what suggestions will be accepted, and when to awaken. Therefore, a hypnotyized person cannot be forever "lost" if the therapist should fall dead during an induction or while the patient is deep in trance.

Experiments by researcher Ernest Hilgard demonstrated how hypnosis can be used to dramatically alter perceptions. After instructing a hypnotized individual not to feel pain in his or her arm, the participant's arm was then placed in ice water. While non-hypnotized individuals had to remove their arm from the water after a few seconds due to the pain, the hypnotized individuals were able to leave their arms in the icy water for several minutes without experiencing pain.

The real origin and essence of the hypnotic condition, is the induction of a habit of abstraction or mental concentration, in which, as in reverie or spontaneous abstraction, the powers of the mind are so much engrossed with a single idea or train of thought, as, for the nonce, to render the individual unconscious of, or indifferently conscious to, all other ideas, impressions, or trains of thought. The hypnotic sleep, therefore, is the very antithesis or opposite mental and physical condition to that which precedes and accompanies common sleep
Hypnosis -- or hypnotherapy -- uses guided relaxation, intense concentration, and focused attention to achieve a heightened state of awareness that is sometimes called a trance. The person's attention is so focused while in this state that anything going on around the person is temporarily blocked out or ignored. In this naturally occurring state, a person may focus his or her attention -- with the help of a trained therapist -- on specific thoughts or tasks.
In Test 1 Mendelsohn and colleagues found that people in the PHA group (who could experience PHA) forgot more details from the movie than people in the non-PHA group (who could not experience PHA). But in Test 2, after the suggestion was cancelled, this memory loss was reversed. People in the PHA group correctly recognized just as many details from the movie as people in the non-PHA group. Somewhat surprisingly, however, the suggestion to forget was selective in its impact. Although people in the PHA group had difficulty remembering the content of the movie following the forget suggestion, they had no difficulty remembering the context in which they saw the movie.
Jump up ^ Braid, J. (1844/1855), "Magic, Mesmerism, Hypnotism, etc., etc. Historically and Physiologically Considered", The Medical Times, Vol.11, No.272, (7 December 1844), pp.203-204, No.273, (14 December 1844), p.224-227, No.275, (28 December 1844), pp.270-273, No.276, (4 January 1845), pp.296-299, No.277, (11 January 1845), pp.318-320, No.281, (8 February 1845), pp.399-400, and No.283, (22 February 1845), pp.439-441: at p.203.
Tai chi is a gentle system of exercises originating from China. The best known example is the “solo form,” a series of slow and graceful movements that follow a set pattern. It is said to improve strength, balance, and mental calmness. Qigong (pronounced “chi kung”) is another traditional Chinese system of therapeutic exercises. Practitioners teach meditation, physical movements, and breathing exercises to improve the flow of Qi, the Chinese term for body energy.
Evidence from randomized controlled trials indicates that hypnosis, relaxation, and meditation techniques can reduce anxiety, particularly that related to stressful situations, such as receiving chemotherapy (see box). They are also effective for insomnia, particularly when the techniques are integrated into a package of cognitive therapy (including, for example, sleep hygiene). A systematic review showed that hypnosis enhances the effects of cognitive behavioral therapy for conditions such as phobia, obesity, and anxiety.

Researchers have used PHA as a laboratory analogue of functional amnesia because these conditions share several similar features. Case reports of functional amnesia, for instance, describe men and women who, following a traumatic experience such as a violent sexual assault or the death of a loved one, are unable to remember part or all of their personal past. However, as in PHA, they might still show “implicit” evidence of the forgotten events. For instance, they might unconsciously dial the phone number of a family member whom they can’t consciously recall. (In contrast, explicit memories are those we consciously have access to, such as remembering a childhood birthday or what you had for dinner last night.)  And, as suddenly as they lost their memories, they can just as suddenly recover them.
Sometimes those shoulds and shouldn'ts seem to only take us so far, before we reach a seemingly insurmountable hurdle that even the strongest willpower just can't quite conquer. This is because we're trying to address these issues on a purely conscious level, which is similar to applying a bandaid over an internal wound. Sooner or later, we need to deal with the root cause.
Charcot operated a clinic at the Pitié-Salpêtrière Hospital (thus, known as the "Paris School" or the "Salpêtrière School"), while Bernheim had a clinic in Nancy (known as the "Nancy School"). Charcot, who was influenced more by the Mesmerists, argued that hypnotism was an abnormal state of nervous functioning found only in certain hysterical women. He claimed that it manifested in a series of physical reactions that could be divided into distinct stages. Bernheim argued that anyone could be hypnotised, that it was an extension of normal psychological functioning, and that its effects were due to suggestion. After decades of debate, Bernheim's view dominated. Charcot's theory is now just a historical curiosity.[59]
In 1974, Theodore X. Barber and his colleagues published a review of the research which argued, following the earlier social psychology of Theodore R. Sarbin, that hypnotism was better understood not as a "special state" but as the result of normal psychological variables, such as active imagination, expectation, appropriate attitudes, and motivation.[16] Barber introduced the term "cognitive-behavioral" to describe the nonstate theory of hypnotism, and discussed its application to behavior therapy.