People who practice hypnotism in a clinical setting have long argued that the hypnotized patient enters an altered state of consciousness. Even if you’ve never undergone hypnotherapy, chances are you’ve experienced this state yourself. “It’s like getting so caught up in a good movie that you forget you’re watching a movie, and you enter the imagined world,” said Dr. David Spiegel, a psychiatrist and the medical director of Stanford University’s Center for Integrative Medicine.
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.
In the 1950s, Milton H. Erickson developed a radically different approach to hypnotism, which has subsequently become known as "Ericksonian hypnotherapy" or "Neo-Ericksonian hypnotherapy." Erickson made use of an informal conversational approach with many clients and complex language patterns, and therapeutic strategies. This divergence from tradition led some of his colleagues, including Andre Weitzenhoffer, to dispute whether Erickson was right to label his approach "hypnosis" at all.