Researchers have used PHA as a laboratory analogue of functional amnesia because these conditions share several similar features. Case reports of functional amnesia, for instance, describe men and women who, following a traumatic experience such as a violent sexual assault or the death of a loved one, are unable to remember part or all of their personal past. However, as in PHA, they might still show “implicit” evidence of the forgotten events. For instance, they might unconsciously dial the phone number of a family member whom they can’t consciously recall. (In contrast, explicit memories are those we consciously have access to, such as remembering a childhood birthday or what you had for dinner last night.)  And, as suddenly as they lost their memories, they can just as suddenly recover them.
Findings from randomized controlled trials support the use of various relaxation techniques for treating both acute and chronic pain, although 2 recent systematic reviews suggest that methodologic flaws may compromise the reliability of these findings. Randomized trials have shown hypnosis is valuable for patients with asthma and irritable bowel syndrome, yoga is helpful for patients with asthma, and tai chi helps to reduce falls and fear of falling in elderly people. Evidence from systematic reviews shows hypnosis and relaxation techniques are probably not of general benefit in stopping smoking or substance misuse or in treating hypertension.​hypertension.,​,
In this special mental state, people feel uninhibited and relaxed. Presumably, this is because they tune out the worries and doubts that normally keep their actions in check. You might experience the same feeling while watching a movie: As you get engrossed in the plot, worries about your job, family, etc. fade away, until all you're thinking about is what's up on the screen.
In 1996, as a result of a three-year research project led by Lindsay B. Yeates, the Australian Hypnotherapists Association[48] (founded in 1949), the oldest hypnotism-oriented professional organization in Australia, instituted a peer-group accreditation system for full-time Australian professional hypnotherapists, the first of its kind in the world, which "accredit[ed] specific individuals on the basis of their actual demonstrated knowledge and clinical performance; instead of approving particular 'courses' or approving particular 'teaching institutions'" (Yeates, 1996, p.iv; 1999, p.xiv).[49] The system was further revised in 1999.[50]

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.[63] 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.[64][65] 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.

It is used for a wide variety of applications, and studies into its efficacy are often of poor quality[2] 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",[3] that there is no evidence[4][5] or insufficient evidence[6][7] for efficacy.