During hypnosis, a person is said to have heightened focus and concentration. The person can concentrate intensely on a specific thought or memory, while blocking out sources of distraction.[7] Hypnotised subjects are said to show an increased response to suggestions.[8] Hypnosis is usually induced by a procedure known as a hypnotic induction involving a series of preliminary instructions and suggestion. The use of hypnotism for therapeutic purposes is referred to as "hypnotherapy", while its use as a form of entertainment for an audience is known as "stage hypnosis". Stage hypnosis is often performed by mentalists practicing the art form of mentalism.
It appears to me, that the general conclusions established by Mesmer's practice, with respect to the physical effects of the principle of imagination (more particularly in cases where they co-operated together), are incomparably more curious than if he had actually demonstrated the existence of his boasted science [of "animal magnetism"]: nor can I see any good reason why a physician, who admits the efficacy of the moral [i.e., psychological] agents employed by Mesmer, should, in the exercise of his profession, scruple to copy whatever processes are necessary for subjecting them to his command, any more than that he should hesitate about employing a new physical agent, such as electricity or galvanism.[54]
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.
Abnormal results can occur in instances where amateurs, who know the fundamentals of hypnosis, entice friends to become their experimental subjects. Their lack of full understanding can lead to immediate consequences, which can linger for some time after the event. If, for example, the amateur plants the suggestion that the subject is being bitten by mosquitoes, the subject would naturally scratch where the bites were perceived. When awakened from the trance, if the amateur forgets to remove the suggestion, the subject will continue the behavior. Left unchecked, the behavior could land the subject in a physician's office in an attempt to stop the itching and scratching cycle. If the physician is astute enough to question the genesis of the behavior and hypnosis is used to remove the suggestion, the subject may experience long-term negative emotional distress and anger upon understanding exactly what happened. The lack of full understanding, complete training, and supervised experience on the part of the amateur places the subject at risk.

“I arrived at the Hypnotherapy Academy of America believing that I had paid for and would receive the most comprehensive hypnotherapy training in the world. What I didn’t expect, however, was to find myself in an environment where I would have so many profound life transforming experiences. By the end of the second week I was completely in awe and felt that our class had already gotten more than our money’s worth. Upon completion of the course, I feel sure of two things. First, that I’m fully prepared to begin a successful hypnotherapy practice. Second, that my life will never be the same again.”

Hypnotherapy has been studied for the treatment of irritable bowel syndrome.[117][118] Hypnosis for IBS has received moderate support in the National Institute for Health and Clinical Excellence guidance published for UK health services.[119] It has been used as an aid or alternative to chemical anesthesia,[120][121][122] and it has been studied as a way to soothe skin ailments.[123]
Hypnosis is not a dangerous procedure. It is not mind control or brainwashing. A therapist cannot make a person do something embarrassing or that the person doesn't want to do. The greatest risk, as discussed above, is that false memories can potentially be created and that it may be less effective than pursuing other, more established and traditional psychiatric treatments.
In no way are the Hypnotherapy Academy’s services to be interpreted as providing medical or psychiatric services. Hypnotherapy services are not offered as a replacement for counseling, psychotherapy, psychiatric or medical treatment. Hypnotherapy is an educational process that facilitates access to internal resources that assist people in increasing motivation, or altering behavior patterns to create positive change. The education of hypnotherapy is classified under Human Services in the Health and Human Services Division of the Classification of Instructional Programs by the United States Department of Education.

Systems theory, in this context, may be regarded as an extension of Braid's original conceptualization of hypnosis as involving "the brain and nervous system generally".[74](p31) Systems theory considers the nervous system's organization into interacting subsystems. Hypnotic phenomena thus involve not only increased or decreased activity of particular subsystems, but also their interaction. A central phenomenon in this regard is that of feedback loops, which suggest a mechanism for creating hypnotic phenomena.[183]
Once the person is in the trance state, and is in a safe seated position, you can use the power of suggestion on your hypnotized subject. For example, you can tell them that when you count to three that they will open their eyes but that they will not remember their name. Then count to three and tell them to open their eyes. When their eyes are open, ask them to tell you their name. They will be amazed that they can't remember their own name.
State theorists interpret the effects of hypnotism as due primarily to a specific, abnormal, and uniform psychological or physiological state of some description, often referred to as "hypnotic trance" or an "altered state of consciousness". Nonstate theorists rejected the idea of hypnotic trance and interpret the effects of hypnotism as due to a combination of multiple task-specific factors derived from normal cognitive, behavioural, and social psychology, such as social role-perception and favorable motivation (Sarbin), active imagination and positive cognitive set (Barber), response expectancy (Kirsch), and the active use of task-specific subjective strategies (Spanos). The personality psychologist Robert White is often cited as providing one of the first nonstate definitions of hypnosis in a 1941 article:
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.