Émile Coué (1857–1926) assisted Ambroise-Auguste Liébeault for around two years at Nancy. After practising for several months employing the "hypnosis" of Liébeault and Bernheim's Nancy School, he abandoned their approach altogether. Later, Coué developed a new approach (c.1901) based on Braid-style "hypnotism", direct hypnotic suggestion, and ego-strengthening which eventually became known as La méthode Coué. According to Charles Baudouin, Coué founded what became known as the New Nancy School, a loose collaboration of practitioners who taught and promoted his views. Coué's method did not emphasise "sleep" or deep relaxation, but instead focused upon autosuggestion involving a specific series of suggestion tests. Although Coué argued that he was no longer using hypnosis, followers such as Charles Baudouin viewed his approach as a form of light self-hypnosis. Coué's method became a renowned self-help and psychotherapy technique, which contrasted with psychoanalysis and prefigured self-hypnosis and cognitive therapy.
Hypnosis for weight loss or to quit addictive behaviors like smoking or drinking, is how most people think of hypnosis. While people do often seek hypnosis therapy for these reasons, there are other reasons too. People may see a hypnotherapist before and during childbirth or to increase self-esteem. It can also be used to deal with chronic pain, insomnia, anxiety, or treat irritable bowel syndrome.
“That study changed the whole landscape,” said Dave Patterson, a psychologist at the University of Washington in Seattle, who has been using hypnosis since the 1980s to help burn victims withstand the intense pain that comes with the necessary but excruciating bandage removal and wound cleaning. Since the ’90s, other well-designed, controlled studies have been published showing similar changes in brain activity. In another slightly trippy example, researchers suggested to people in a hypnotic state that the vibrant primary colors found in paintings by Piet Mondrian were actually shades of gray. “Brain-scan results of these participants showed altered activity in fusiform regions involved in color processing,” notes psychologist Christian Jarrett.
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.
It is used for a wide variety of applications, and studies into its efficacy are often of poor quality which makes it difficult to determine efficacy. Several recent meta-analyses and systematic reviews of the literature on various conditions have concluded that the efficacy of hypnotherapy is "not verified", that there is no evidence or insufficient evidence for efficacy.