One obvious risk to patients is the insufficiently trained therapist. The inadequately trained therapist can cause harm and distort the normally pleasant experience of hypnotherapy. A second risk for patients is the unscrupulous practitioner who may be both inadequately trained and may have some hidden agenda. These rare individuals are capable of causing great harm to the patient and to the profession. As mentioned above, the patient should carefully scrutinize their chosen therapist before submitting themselves to this dynamic form of therapy.
Controversy surrounds the use of hypnotherapy to retrieve memories, especially those from early childhood or (supposed) past-lives. The American Medical Association and the American Psychological Association caution against recovered-memory therapy in cases of alleged childhood trauma, stating that "it is impossible, without corroborative evidence, to distinguish a true memory from a false one." Past life regression, meanwhile, is often viewed with skepticism.
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.
When James Braid first described hypnotism, he did not use the term "suggestion" but referred instead to the act of focusing the conscious mind of the subject upon a single dominant idea. Braid's main therapeutic strategy involved stimulating or reducing physiological functioning in different regions of the body. In his later works, however, Braid placed increasing emphasis upon the use of a variety of different verbal and non-verbal forms of suggestion, including the use of "waking suggestion" and self-hypnosis. Subsequently, Hippolyte Bernheim shifted the emphasis from the physical state of hypnosis on to the psychological process of verbal suggestion:
Although there are different techniques, clinical hypnotherapy is generally performed in a calm, therapeutic environment. The therapist will guide you into a relaxed, focused state and ask you to think about experiences and situations in positive ways that can help you change the way you think and behave. Unlike some dramatic portrayals of hypnosis in movies, books, or on stage, you will not be unconscious, asleep, or in any way out of control of yourself. You will hear the therapist’s suggestions, but it is up to you to decide whether or not to act on them.