“Learning hypnotherapy does not commit you to drastically changing your therapy practice,” says hypnotherapist Catherine Reiss. “The training will allow you to more quickly and effectively get to the cause of your clients’ unwanted behaviors and the feelings they present with it, but it also facilitates the use of trance in more traditional formats.”
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.
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.
Stage hypnosis is a form of entertainment, traditionally employed in a club or theatre before an audience. Due to stage hypnotists' showmanship, many people believe that hypnosis is a form of mind control. Stage hypnotists typically attempt to hypnotise the entire audience and then select individuals who are "under" to come up on stage and perform embarrassing acts, while the audience watches. However, the effects of stage hypnosis are probably due to a combination of psychological factors, participant selection, suggestibility, physical manipulation, stagecraft, and trickery.[152] The desire to be the centre of attention, having an excuse to violate their own fear suppressors, and the pressure to please are thought to convince subjects to "play along".[153] Books by stage hypnotists sometimes explicitly describe the use of deception in their acts; for example, Ormond McGill's New Encyclopedia of Stage Hypnosis describes an entire "fake hypnosis" act that depends upon the use of private whispers throughout.
Milton Erickson (1901–1980), the founding president of the American Society for Clinical Hypnosis and a fellow of the American Psychiatric Association, the American Psychological Association, and the American Psychopathological Association, was one of the most influential post-war hypnotherapists. He wrote several books and journal articles on the subject. During the 1960s, Erickson popularized a new branch of hypnotherapy, known as Ericksonian therapy, characterised primarily by indirect suggestion, "metaphor" (actually analogies), confusion techniques, and double binds in place of formal hypnotic inductions. However, the difference between Erickson's methods and traditional hypnotism led contemporaries such as André Weitzenhoffer to question whether he was practising "hypnosis" at all, and his approach remains in question.
Although he rejected the transcendental/metaphysical interpretation given to these phenomena outright, Braid accepted that these accounts of Oriental practices supported his view that the effects of hypnotism could be produced in solitude, without the presence of any other person (as he had already proved to his own satisfaction with the experiments he had conducted in November 1841); and he saw correlations between many of the "metaphysical" Oriental practices and his own "rational" neuro-hypnotism, and totally rejected all of the fluid theories and magnetic practices of the mesmerists. As he later wrote:
Azam's enthusiasm for hypnotism influenced Ambroise-Auguste Liébeault, a country doctor. Hippolyte Bernheim discovered Liébeault's enormously popular group hypnotherapy clinic and subsequently became an influential hypnotist. The study of hypnotism subsequently revolved around the fierce debate between Bernheim and Jean-Martin Charcot, the two most influential figures in late 19th-century hypnotism.
Olness thinks there must be something about the intense mental imagery that comes with a hypnotic state. One little boy she worked with told her he was imagining that he was touching the sun. Whether such visions activate different parts of the brain than those associated with rational thought is less clear. As Olness says, “We’re a long way from specifics on that.”

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.
We know it is hard to sort out all the different claims made by some so-called “hypnosis schools and boards.” Stay away from “distance learning” or correspondence courses that claim to certify you as a clinical hypnotherapist. Hypnosis and hypnotherapy is a healing art based on scientific methods. Only basic hypnotherapy theory can be obtained from the right books or videos. Effectiveness is unlikely without live demonstrations, in-depth and advanced discussion, question and answer opportunities and supervised clinical practice.  Just as correspondence courses are inappropriate for counselors, medical doctors and massage therapists, they are wrong for people who want to be effective and successful clinical hypnotherapists.
In a July 2001 article for Scientific American titled "The Truth and the Hype of Hypnosis", Michael Nash wrote that, "using hypnosis, scientists have temporarily created hallucinations, compulsions, certain types of memory loss, false memories, and delusions in the laboratory so that these phenomena can be studied in a controlled environment."[116]
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

Whereas the older "depth scales" tried to infer the level of "hypnotic trance" from supposed observable signs such as spontaneous amnesia, most subsequent scales have measured the degree of observed or self-evaluated responsiveness to specific suggestion tests such as direct suggestions of arm rigidity (catalepsy). The Stanford, Harvard, HIP, and most other susceptibility scales convert numbers into an assessment of a person's susceptibility as "high", "medium", or "low". Approximately 80% of the population are medium, 10% are high, and 10% are low. There is some controversy as to whether this is distributed on a "normal" bell-shaped curve or whether it is bi-modal with a small "blip" of people at the high end.[45] Hypnotizability Scores are highly stable over a person's lifetime. Research by Deirdre Barrett has found that there are two distinct types of highly susceptible subjects, which she terms fantasizers and dissociaters. Fantasizers score high on absorption scales, find it easy to block out real-world stimuli without hypnosis, spend much time daydreaming, report imaginary companions as a child, and grew up with parents who encouraged imaginary play. Dissociaters often have a history of childhood abuse or other trauma, learned to escape into numbness, and to forget unpleasant events. Their association to "daydreaming" was often going blank rather than creating vividly recalled fantasies. Both score equally high on formal scales of hypnotic susceptibility.[46][47][48]

There are a number of articles, books, and audio guides available for free or purchase online that can give you pointers or guides for self hypnosis. There are also hundreds of self hypnosis apps available for download. However, it is important to note that many of these apps have not been scientifically tested, and are not proven to work, but if they help relax you, there’s little downside.
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.
It would be difficult to find an area of scientific interest more beset by divided professional opinion and contradictory experimental evidence…No one can say whether hypnosis is a qualitatively unique state with some physiological and conditioned response components or only a form of suggestion induced by high motivation and a positive relationship between hypnotist and subject…T.X. Barber has produced "hypnotic deafness" and "hypnotic blindness", analgesia and other responses seen in hypnosis—all without hypnotizing anyone…Orne has shown that unhypnotized persons can be motivated to equal and surpass the supposed superhuman physical feats seen in hypnosis.[148]
People have been entering into hypnotic-type trances for thousands of years. In many cultures and religions, it was regarded as a form of meditation. Modern day hypnosis, however, started in the late 18th century and was made popular by Franz Mesmer, a German physician who became known as the father of ‘modern hypnotism’. In fact, hypnosis used to be known as ‘Mesmerism’ as it was named after Mesmer.
Since hypnotherapy is an adjunct form of therapy, used along with other forms of psychological or medical treatment, there are many applications. Hypnotherapy can be used to treat anxiety, phobias, substance abuse including tobacco, sexual dysfunction, undesirable spontaneous behaviors, and bad habits. It can be used to help improve sleep, learning disorders, communication, and relationship issues. Hypnotherapy can aid in pain management and help resolve medical conditions such as digestive disorders, skin issues, and gastrointestinal side effects of pregnancy and chemotherapy. It can also be used by dentists to help patients control their fears or to treat teeth grinding and other oral conditions.