Mesmer's original interest was in the effect of celestial bodies on human lives. He later became interested in the effects of magnetism, and found that magnets could have tremendous healing effects on the human body. Mesmer believed that the human body contained a magnetic fluid that promoted health and well being. It was thought that any blockage to the normal flow of this magnetic fluid would result in illness, and that the use of the mesmerism technique could restore the normal flow.
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]
The term "hypnosis" comes from the ancient Greek word ὕπνος hypnos, "sleep", and the suffix -ωσις -osis, or from ὑπνόω hypnoō, "put to sleep" (stem of aorist hypnōs-) and the suffix -is.[9][10] The words "hypnosis" and "hypnotism" both derive from the term "neuro-hypnotism" (nervous sleep), all of which were coined by Étienne Félix d'Henin de Cuvillers in 1820. These words were popularized in English by the Scottish surgeon James Braid (to whom they are sometimes wrongly attributed) around 1841. Braid based his practice on that developed by Franz Mesmer and his followers (which was called "Mesmerism" or "animal magnetism"), but differed in his theory as to how the procedure worked.

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.

Hypnotic music became an important part in the development of a ‘physiological psychology’ that regarded the hypnotic state as an ‘automatic’ phenomenon that links to physical reflex. In their experiments with sound hypnosis, Jean-Martin Charcot used gongs and tuning forks, and Ivan Pavlov used bells. The intention behind their experiments was to prove that physiological response to sound could be automatic, bypassing the conscious mind.[155]

Not every person is hypnotizable to the same degree; some aren’t hypnotizable at all. “Hypnotizability … is modestly correlated with absorption, a personality construct reflecting a disposition to enter states of narrowed or expanded attention and a blurring of boundaries between oneself and the object of perception,” writes John F. Kihlstrom, a psychologist at the University of California, Berkeley, in a 2013 paper in Cortex. “Absorption, in turn, is related to ‘openness to experience,’ one of the ‘Big Five” dimensions of personality.”
the induction of a specific altered state (trance) for memory retrieval, relaxation, or suggestion. Hypnotherapy is often used to alter habits (e.g., smoking, obesity), treat biological mechanisms such as hypertension or cardiac arrhythmias, deal with the symptoms of a disease, alter an individual's reaction to disease, and affect an illness and its course through the body.
Hypnotherapy involves achieving a psychological state of awareness that is different from the ordinary state of consciousness. While in a hypnotic state, a variety of phenomena can occur. These phenomena include alterations in memory, heightened susceptibility to suggestion, paralysis, sweating, and blushing. All of these changes can be produced or removed in the hypnotic state. Many studies have shown that roughly 90% of the population is capable of being hypnotized.
Hypnosis has been used as a supplemental approach to cognitive behavioral therapy since as early as 1949. Hypnosis was defined in relation to classical conditioning; where the words of the therapist were the stimuli and the hypnosis would be the conditioned response. Some traditional cognitive behavioral therapy methods were based in classical conditioning. It would include inducing a relaxed state and introducing a feared stimuli. One way of inducing the relaxed state was through hypnosis.[77]
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]
Gruzelier and his colleagues studied brain activity using an fMRI while subjects completed a standard cognitive exercise, called the Stroop task. The team screened subjects before the study and chose 12 that were highly susceptible to hypnosis and 12 with low susceptibility. They all completed the task in the fMRI under normal conditions and then again under hypnosis. Throughout the study, both groups were consistent in their task results, achieving similar scores regardless of their mental state. During their first task session, before hypnosis, there were no significant differences in brain activity between the groups. But under hypnosis, Gruzelier found that the highly susceptible subjects showed significantly more brain activity in the anterior cingulate gyrus than the weakly susceptible subjects. This area of the brain has been shown to respond to errors and evaluate emotional outcomes. The highly susceptible group also showed much greater brain activity on the left side of the prefrontal cortex than the weakly susceptible group. This is an area involved with higher level cognitive processing and behaviour.[178][179]
It’s important to remember that depression, along with severe and chronic mental illnesses such as bipolar disorder and schizophrenia, also affect a person’s physical health. Depression is more than just feeling sad or having negative thoughts. It’s a condition where the chemicals in your brain are imbalanced. Hypnotherapy is a complementary therapy, and it shouldn’t be the only therapy a person uses to enhance their mental health.
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:

"NOW AT TWO LOCATIONS: Donna is a warm, dedicated, and enthusiastic therapist with the experience, expertise and empathy to guide her clients through a productive and successful counseling experience. She is skilled in assessing a client's situation and providing the therapeutic climate that will promote the highest level of counseling achievement. Donna is very creative in her approach to counseling and is experienced in a broad spectrum of techniques that can be tailored to each client's individual needs. Donna is noted for her ability to help clients redirect negative and self-destructive behaviors and become better adjusted to their life situations."

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.
For some psychologists who uphold the altered state theory of hypnosis, pain relief in response to hypnosis is said to be the result of the brain's dual-processing functionality. This effect is obtained either through the process of selective attention or dissociation, in which both theories involve the presence of activity in pain receptive regions of the brain, and a difference in the processing of the stimuli by the hypnotised subject.[137]
The Federal Dictionary of Occupational Titles describes the job of the hypnotherapist: "Induces hypnotic state in client to increase motivation or alter behavior patterns: Consults with client to determine nature of problem. Prepares client to enter hypnotic state by explaining how hypnosis works and what client will experience. Tests subject to determine degree of physical and emotional suggestibility. Induces hypnotic state in client, using individualized methods and techniques of hypnosis based on interpretation of test results and analysis of client's problem. May train client in self-hypnosis conditioning. GOE: 10.02.02 STRENGTH: S GED: R4 M3 L4 SVP: 7 DLU: 77"[8]