The first neuropsychological theory of hypnotic suggestion was introduced early by James Braid who adopted his friend and colleague William Carpenter's theory of the ideo-motor reflex response to account for the phenomenon of hypnotism. Carpenter had observed from close examination of everyday experience that, under certain circumstances, the mere idea of a muscular movement could be sufficient to produce a reflexive, or automatic, contraction or movement of the muscles involved, albeit in a very small degree. Braid extended Carpenter's theory to encompass the observation that a wide variety of bodily responses besides muscular movement can be thus affected, for example, the idea of sucking a lemon can automatically stimulate salivation, a secretory response. Braid, therefore, adopted the term "ideo-dynamic", meaning "by the power of an idea", to explain a broad range of "psycho-physiological" (mind–body) phenomena. Braid coined the term "mono-ideodynamic" to refer to the theory that hypnotism operates by concentrating attention on a single idea in order to amplify the ideo-dynamic reflex response. Variations of the basic ideo-motor, or ideo-dynamic, theory of suggestion have continued to exercise considerable influence over subsequent theories of hypnosis, including those of Clark L. Hull, Hans Eysenck, and Ernest Rossi. It should be noted that in Victorian psychology the word "idea" encompasses any mental representation, including mental imagery, memories, etc.
Hence, the social constructionism and role-taking theory of hypnosis suggests that individuals are enacting (as opposed to merely playing) a role and that really there is no such thing as a hypnotic trance. A socially constructed relationship is built depending on how much rapport has been established between the "hypnotist" and the subject (see Hawthorne effect, Pygmalion effect, and placebo effect).
Look for a hypnotherapist who is a member of the American Society of Clinical Hypnosis (ASCH) or the Society for Clinical and Experimental Hypnosis. To be a member of either of these organizations, a hypnotherapist must have a doctorate level degree in medicine, dentistry, or psychology, or a master’s degree in nursing, social work, psychology, or marital/family therapy plus a specific number of hours of approved training in hypnotherapy. In some cases, accredited, doctoral-level practitioners of alternative health care, such traditional Chinese medicine, may also be approved for membership. Of course, in addition to looking at qualifications, you should also find a hypnotherapist with whom you feel confident and comfortable in a therapeutic relationship.