Confusion can occur when one seeks a hypnotherapist, as a result of the various titles, certifications, and licenses in the field. Many states do not regulate the title "hypnotist" or "hypnotherapist," so care must be exercised when selecting someone to see. As a rule, it is best to consult a professional in the field of mental health or medicine, although alternative sources for hypnosis are available. Care must be taken also by the therapist to ensure adequate training and sufficient experience for rendering this specialized service. The therapist must be well grounded in a psychotherapeutic approach before undertaking the use of hypnotherapy. Professionals should not attempt hypnotherapy with any disorder for which they would not use traditional therapeutic approaches. The patient seeking hypnotherapy is reminded that unskilled or amateur hypnotists can cause harm and should not be consulted for the purpose of implementing positive change in an individual's life. The detrimental effects of being subjected to amateur or inadequately trained persons can be severe and long lasting. (See abnormal results below.)
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. 

Braid can be taken to imply, in later writings, that hypnosis is largely a state of heightened suggestibility induced by expectation and focused attention. In particular, Hippolyte Bernheim became known as the leading proponent of the "suggestion theory" of hypnosis, at one point going so far as to declare that there is no hypnotic state, only heightened suggestibility. There is a general consensus that heightened suggestibility is an essential characteristic of hypnosis. In 1933, Clark L. Hull wrote:
“Before attending the Hypnotherapy Academy of America, I had already had over 500 hours of hypnotherapy training; however, I felt that I was missing some important concepts and skills, so I went to the Academy hoping to get what I was unable to get from other training. My goals were completely fulfilled. I received a solid foundation in hypnosis and hypnotherapy and learned how to take hypnotherapy to new heights and greater depths. As a result of the Academy training, I now do hypnotic work more efficiently and more effectively than with my prior training. Because the quality of my work as a hypnotherapist has significantly improved through the Academy training, I can offer greater value to my patients, and I can more easily market my practice.

Placing persons in a drowsy, sleeplike state in which they allegedly become vulnerable to the suggestions made by the hypnotist. Hypnosis may also be used to tap into the unconscious and is often characterized by vivid recall of memories and fantasies. These properties make hypnosis a useful tool in psychotherapy. Hypnosis also has sinister implications, for subjects may be manipulated to perform embarrassing actions or be susceptible to carrying out the hypnotist's commands after the hypnosis session (posthypnotic suggestion).

The American Psychological Association published a study comparing the effects of hypnosis, ordinary suggestion, and placebo in reducing pain. The study found that highly suggestible individuals experienced a greater reduction in pain from hypnosis compared with placebo, whereas less suggestible subjects experienced no pain reduction from hypnosis when compared with placebo. Ordinary non-hypnotic suggestion also caused reduction in pain compared to placebo, but was able to reduce pain in a wider range of subjects (both high and low suggestible) than hypnosis. The results showed that it is primarily the subject's responsiveness to suggestion, whether within the context of hypnosis or not, that is the main determinant of causing reduction in pain.[138]
The LAP BAND® procedure was approved by my insurance, but I just did not want to go through with it. I needed to do something to reduce my weight and the virtual gastric band hypnosis sounded more like something I could live with. I am eating much smaller portions and feeling so much better. My only problem is my clothes are too big so I need to go shopping.
In 1784, at the request of King Louis XVI, a Board of Inquiry started to investigate whether animal magnetism existed. Among the board members were founding father of modern chemistry Antoine Lavoisier, Benjamin Franklin, and an expert in pain control, Joseph-Ignace Guillotin. They investigated the practices of a disaffected student of Mesmer, one Charles d'Eslon (1750–1786), and though they concluded that Mesmer's results were valid, their placebo-controlled experiments using d'Eslon's methods convinced them that mesmerism was most likely due to belief and imagination rather than to an invisible energy ("animal magnetism") transmitted from the body of the mesmerist.
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]

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.