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Thursday, December 19, 2019

Hypnosis

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Hypnosis
 
Hypnotic Séance (1887) by Richard Bergh
 
Hypnosis
Une leçon clinique à la Salpêtrière.jpg
Charcot demonstrating hypnosis on a "hysterical" Salpêtrière patient, "Blanche" (Marie Wittmann), who is supported by Joseph Babiński.
MeSHD006990


Hypnosis is a human condition involving focused attention, reduced peripheral awareness, and an enhanced capacity to respond to suggestion.

There are competing theories explaining hypnosis and related phenomena. Altered state theories see hypnosis as an altered state of mind or trance, marked by a level of awareness different from the ordinary state of consciousness. In contrast, nonstate theories see hypnosis as, variously, a type of placebo effect, a redefinition of an interaction with a therapist or form of imaginative role enactment.

During hypnosis, a person is said to have heightened focus and concentration. Hypnotized subjects are said to show an increased response to suggestions. Hypnosis usually begins with a hypnotic induction involving a series of preliminary instructions and suggestion. The use of hypnotism for therapeutic purposes is referred to as "hypnotherapy", while its use as a form of entertainment for an audience is known as "stage hypnosis". Stage hypnosis is often performed by mentalists practicing the art form of mentalism

Hypnosis for pain management "is likely to decrease acute and chronic pain in most individuals." The use of hypnosis in other contexts, such as a form of therapy to retrieve and integrate early trauma, is controversial within the medical or psychological mainstream. Research indicates that hypnotizing an individual may aid the formation of false memories, and that hypnosis "does not help people recall events more accurately."

Etymology

The term "hypnosis" comes from the ancient Greek word ὑπνος hypnos, "sleep", and the suffix -ωσις -osis, or from ὑπνόω hypnoō, "put to sleep" (stem of aorist hypnōs-) and the suffix -is. The words "hypnosis" and "hypnotism" both derive from the term "neuro-hypnotism" (nervous sleep), all of which were coined by Étienne Félix d'Henin de Cuvillers in 1820. These words were popularized in English by the Scottish surgeon James Braid (to whom they are sometimes wrongly attributed) around 1841. Braid based his practice on that developed by Franz Mesmer and his followers (which was called "Mesmerism" or "animal magnetism"), but differed in his theory as to how the procedure worked. 

Characteristics

A person in a state of hypnosis has focused attention, and has increased suggestibility.
The hypnotized individual appears to heed only the communications of the hypnotist and typically responds in an uncritical, automatic fashion while ignoring all aspects of the environment other than those pointed out by the hypnotist. In a hypnotic state an individual tends to see, feel, smell, and otherwise perceive in accordance with the hypnotist's suggestions, even though these suggestions may be in apparent contradiction to the actual stimuli present in the environment. The effects of hypnosis are not limited to sensory change; even the subject's memory and awareness of self may be altered by suggestion, and the effects of the suggestions may be extended (posthypnotically) into the subject's subsequent waking activity.
It could be said that hypnotic suggestion is explicitly intended to make use of the placebo effect. For example, in 1994, Irving Kirsch characterised hypnosis as a "nondeceptive placebo", i.e., a method that openly makes use of suggestion and employs methods to amplify its effects.

In Trance on Trial, a 1989 text directed at the legal profession, legal scholar Alan W. Scheflin and psychologist Jerrold Lee Shapiro observed that the "deeper" the hypnotism, the more likely a particular characteristic is to appear, and the greater extent to which it is manifested. Scheflin and Shapiro identified 20 separate characteristics that hypnotized subjects might display: "dissociation"; "detachment"; "suggestibility", "ideosensory activity"; "catalepsy"; "ideomotor responsiveness"; "age regression"; "revivification"; "hypermnesia"; "[automatic or suggested] amnesia"; "posthypnotic responses"; "hypnotic analgesia and anesthesia"; "glove anesthesia"; "somnambulism"; "automatic writing"; "time distortion"; "release of inhibitions"; "change in capacity for volitional activity"; "trance logic"; and "effortless imagination". 

Definitions


Historical definitions

The earliest definition of hypnosis was given by Braid, who coined the term "hypnotism" as an abbreviation for "neuro-hypnotism", or nervous sleep, which he contrasted with normal sleep, and defined as: "a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye, on one object, not of an exciting nature."

Braid elaborated upon this brief definition in a later work, Hypnotic Therapeutics:
The real origin and essence of the hypnotic condition, is the induction of a habit of abstraction or mental concentration, in which, as in reverie or spontaneous abstraction, the powers of the mind are so much engrossed with a single idea or train of thought, as, for the nonce, to render the individual unconscious of, or indifferently conscious to, all other ideas, impressions, or trains of thought. The hypnotic sleep, therefore, is the very antithesis or opposite mental and physical condition to that which precedes and accompanies common sleep
Therefore, Braid defined hypnotism as a state of mental concentration that often leads to a form of progressive relaxation, termed "nervous sleep". Later, in his The Physiology of Fascination (1855), Braid conceded that his original terminology was misleading, and argued that the term "hypnotism" or "nervous sleep" should be reserved for the minority (10%) of subjects who exhibit amnesia, substituting the term "monoideism", meaning concentration upon a single idea, as a description for the more alert state experienced by the others.

A new definition of hypnosis, derived from academic psychology, was provided in 2005, when the Society for Psychological Hypnosis, Division 30 of the American Psychological Association (APA), published the following formal definition:
Hypnosis typically involves an introduction to the procedure during which the subject is told that suggestions for imaginative experiences will be presented. The hypnotic induction is an extended initial suggestion for using one's imagination, and may contain further elaborations of the introduction. A hypnotic procedure is used to encourage and evaluate responses to suggestions. When using hypnosis, one person (the subject) is guided by another (the hypnotist) to respond to suggestions for changes in subjective experience, alterations in perception, sensation, emotion, thought or behavior. Persons can also learn self-hypnosis, which is the act of administering hypnotic procedures on one's own. If the subject responds to hypnotic suggestions, it is generally inferred that hypnosis has been induced. Many believe that hypnotic responses and experiences are characteristic of a hypnotic state. While some think that it is not necessary to use the word "hypnosis" as part of the hypnotic induction, others view it as essential.
Michael Nash provides a list of eight definitions of hypnosis by different authors, in addition to his own view that hypnosis is "a special case of psychological regression":
  1. Janet, near the turn of the century, and more recently Ernest Hilgard ..., have defined hypnosis in terms of dissociation.
  2. Social psychologists Sarbin and Coe ... have described hypnosis in terms of role theory. Hypnosis is a role that people play; they act "as if" they were hypnotised.
  3. T. X. Barber ... defined hypnosis in terms of nonhypnotic behavioural parameters, such as task motivation and the act of labeling the situation as hypnosis.
  4. In his early writings, Weitzenhoffer ... conceptualised hypnosis as a state of enhanced suggestibility. Most recently ... he has defined hypnotism as "a form of influence by one person exerted on another through the medium or agency of suggestion."
  5. Psychoanalysts Gill and Brenman ... described hypnosis by using the psychoanalytic concept of "regression in the service of the ego".
  6. Edmonston ... has assessed hypnosis as being merely a state of relaxation.
  7. Spiegel and Spiegel... have implied that hypnosis is a biological capacity.
  8. Erickson ... is considered the leading exponent of the position that hypnosis is a special, inner-directed, altered state of functioning.
Joe Griffin and Ivan Tyrrell (the originators of the human givens approach) define hypnosis as "any artificial way of accessing the REM state, the same brain state in which dreaming occurs" and suggest that this definition, when properly understood, resolves "many of the mysteries and controversies surrounding hypnosis". They see the REM state as being vitally important for life itself, for programming in our instinctive knowledge initially (after Dement and Jouvet) and then for adding to this throughout life. They explain this by pointing out that, in a sense, all learning is post-hypnotic, which explains why the number of ways people can be put into a hypnotic state are so varied: anything that focuses a person's attention, inward or outward, puts them into a trance.

Hypnotic induction

Hypnosis is normally preceded by a "hypnotic induction" technique. Traditionally, this was interpreted as a method of putting the subject into a "hypnotic trance"; however, subsequent "nonstate" theorists have viewed it differently, seeing it as a means of heightening client expectation, defining their role, focusing attention, etc. There are several different induction techniques. One of the most influential methods was Braid's "eye-fixation" technique, also known as "Braidism". Many variations of the eye-fixation approach exist, including the induction used in the Stanford Hypnotic Susceptibility Scale (SHSS), the most widely used research tool in the field of hypnotism. Braid's original description of his induction is as follows:
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.

The patient must be made to understand that he is to keep the eyes steadily fixed on the object, and the mind riveted on the idea of that one object. It will be observed, that owing to the consensual adjustment of the eyes, the pupils will be at first contracted: They will shortly begin to dilate, and, after they have done so to a considerable extent, and have assumed a wavy motion, if the fore and middle fingers of the right hand, extended and a little separated, are carried from the object toward the eyes, most probably the eyelids will close involuntarily, with a vibratory motion. If this is not the case, or the patient allows the eyeballs to move, desire him to begin anew, giving him to understand that he is to allow the eyelids to close when the fingers are again carried towards the eyes, but that the eyeballs must be kept fixed, in the same position, and the mind riveted to the one idea of the object held above the eyes. In general, it will be found, that the eyelids close with a vibratory motion, or become spasmodically closed.
Braid later acknowledged that the hypnotic induction technique was not necessary in every case, and subsequent researchers have generally found that on average it contributes less than previously expected to the effect of hypnotic suggestions. Variations and alternatives to the original hypnotic induction techniques were subsequently developed. However, this method is still considered authoritative. In 1941, Robert White wrote: "It can be safely stated that nine out of ten hypnotic techniques call for reclining posture, muscular relaxation, and optical fixation followed by eye closure."

Suggestion

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:
I define hypnotism as the induction of a peculiar psychical [i.e., mental] condition which increases the susceptibility to suggestion. Often, it is true, the [hypnotic] sleep that may be induced facilitates suggestion, but it is not the necessary preliminary. It is suggestion that rules hypnotism.
Bernheim's conception of the primacy of verbal suggestion in hypnotism dominated the subject throughout the 20th century, leading some authorities to declare him the father of modern hypnotism.

Contemporary hypnotism uses a variety of suggestion forms including direct verbal suggestions, "indirect" verbal suggestions such as requests or insinuations, metaphors and other rhetorical figures of speech, and non-verbal suggestion in the form of mental imagery, voice tonality, and physical manipulation. A distinction is commonly made between suggestions delivered "permissively" and those delivered in a more "authoritarian" manner. Harvard hypnotherapist Deirdre Barrett writes that most modern research suggestions are designed to bring about immediate responses, whereas hypnotherapeutic suggestions are usually post-hypnotic ones that are intended to trigger responses affecting behaviour for periods ranging from days to a lifetime in duration. The hypnotherapeutic ones are often repeated in multiple sessions before they achieve peak effectiveness.

Conscious and unconscious mind

Some hypnotists view suggestion as a form of communication that is directed primarily to the subject's conscious mind, whereas others view it as a means of communicating with the "unconscious" or "subconscious" mind. These concepts were introduced into hypnotism at the end of the 19th century by Sigmund Freud and Pierre Janet. Sigmund Freud's psychoanalytic theory describes conscious thoughts as being at the surface of the mind and unconscious processes as being deeper in the mind. Braid, Bernheim, and other Victorian pioneers of hypnotism did not refer to the unconscious mind but saw hypnotic suggestions as being addressed to the subject's conscious mind. Indeed, Braid actually defines hypnotism as focused (conscious) attention upon a dominant idea (or suggestion). Different views regarding the nature of the mind have led to different conceptions of suggestion. Hypnotists who believe that responses are mediated primarily by an "unconscious mind", like Milton Erickson, make use of indirect suggestions such as metaphors or stories whose intended meaning may be concealed from the subject's conscious mind. The concept of subliminal suggestion depends upon this view of the mind. By contrast, hypnotists who believe that responses to suggestion are primarily mediated by the conscious mind, such as Theodore Barber and Nicholas Spanos, have tended to make more use of direct verbal suggestions and instructions.

Ideo-dynamic reflex

The first neuropsychological theory of hypnotic suggestion was introduced early by James Braid who adopted his friend and colleague William Carpenter's theory of the ideo-motor reflex response to account for the phenomenon of hypnotism. Carpenter had observed from close examination of everyday experience that, under certain circumstances, the mere idea of a muscular movement could be sufficient to produce a reflexive, or automatic, contraction or movement of the muscles involved, albeit in a very small degree. Braid extended Carpenter's theory to encompass the observation that a wide variety of bodily responses besides muscular movement can be thus affected, for example, the idea of sucking a lemon can automatically stimulate salivation, a secretory response. Braid, therefore, adopted the term "ideo-dynamic", meaning "by the power of an idea", to explain a broad range of "psycho-physiological" (mind–body) phenomena. Braid coined the term "mono-ideodynamic" to refer to the theory that hypnotism operates by concentrating attention on a single idea in order to amplify the ideo-dynamic reflex response. Variations of the basic ideo-motor, or ideo-dynamic, theory of suggestion have continued to exercise considerable influence over subsequent theories of hypnosis, including those of Clark L. Hull, Hans Eysenck, and Ernest Rossi. In Victorian psychology the word "idea" encompasses any mental representation, including mental imagery, memories, etc. 

Susceptibility

Braid made a rough distinction between different stages of hypnosis, which he termed the first and second conscious stage of hypnotism; he later replaced this with a distinction between "sub-hypnotic", "full hypnotic", and "hypnotic coma" stages. Jean-Martin Charcot made a similar distinction between stages which he named somnambulism, lethargy, and catalepsy. However, Ambroise-Auguste Liébeault and Hippolyte Bernheim introduced more complex hypnotic "depth" scales based on a combination of behavioural, physiological, and subjective responses, some of which were due to direct suggestion and some of which were not. In the first few decades of the 20th century, these early clinical "depth" scales were superseded by more sophisticated "hypnotic susceptibility" scales based on experimental research. The most influential were the Davis–Husband and Friedlander–Sarbin scales developed in the 1930s. André Weitzenhoffer and Ernest R. Hilgard developed the Stanford Scale of Hypnotic Susceptibility in 1959, consisting of 12 suggestion test items following a standardised hypnotic eye-fixation induction script, and this has become one of the most widely referenced research tools in the field of hypnosis. Soon after, in 1962, Ronald Shor and Emily Carota Orne developed a similar group scale called the Harvard Group Scale of Hypnotic Susceptibility (HGSHS). 

Whereas the older "depth scales" tried to infer the level of "hypnotic trance" from supposed observable signs such as spontaneous amnesia, most subsequent scales have measured the degree of observed or self-evaluated responsiveness to specific suggestion tests such as direct suggestions of arm rigidity (catalepsy). The Stanford, Harvard, HIP, and most other susceptibility scales convert numbers into an assessment of a person's susceptibility as "high", "medium", or "low". Approximately 80% of the population are medium, 10% are high, and 10% are low. There is some controversy as to whether this is distributed on a "normal" bell-shaped curve or whether it is bi-modal with a small "blip" of people at the high end. Hypnotizability Scores are highly stable over a person's lifetime. Research by Deirdre Barrett has found that there are two distinct types of highly susceptible subjects, which she terms fantasizers and dissociaters. Fantasizers score high on absorption scales, find it easy to block out real-world stimuli without hypnosis, spend much time daydreaming, report imaginary companions as a child, and grew up with parents who encouraged imaginary play. Dissociaters often have a history of childhood abuse or other trauma, learned to escape into numbness, and to forget unpleasant events. Their association to "daydreaming" was often going blank rather than creating vividly recalled fantasies. Both score equally high on formal scales of hypnotic susceptibility.

Individuals with dissociative identity disorder have the highest hypnotisability of any clinical group, followed by those with posttraumatic stress disorder.

History


Precursors

People have been entering into hypnotic-type trances for thousands of years. In many cultures and religions, it was regarded as a form of meditation. Modern day hypnosis, however, started in the late 18th century and was made popular by Franz Mesmer, a German physician who became known as the father of 'modern hypnotism'. In fact, hypnosis used to be known as 'Mesmerism' as it was named after Mesmer. 

Mesmer held the opinion that hypnosis was a sort of mystical force that flows from the hypnotist to the person being hypnotized, but his theory was dismissed by critics who asserted that there is no magical element to hypnotism.

Before long, hypnotism started finding its way into the world of modern medicine. The use of hypnotism in the medical field was made popular by surgeons and physicians like Elliotson and James Esdaile and researchers like James Braid who helped to reveal the biological and physical benefits of hypnotism. According to his writings, Braid began to hear reports concerning various Oriental meditative practices soon after the release of his first publication on hypnotism, Neurypnology (1843). He first discussed some of these oriental practices in a series of articles entitled Magic, Mesmerism, Hypnotism, etc., Historically & Physiologically Considered. He drew analogies between his own practice of hypnotism and various forms of Hindu yoga meditation and other ancient spiritual practices, especially those involving voluntary burial and apparent human hibernation. Braid's interest in these practices stems from his studies of the Dabistān-i Mazāhib, the "School of Religions", an ancient Persian text describing a wide variety of Oriental religious rituals, beliefs, and practices.
Last May [1843], a gentleman residing in Edinburgh, personally unknown to me, who had long resided in India, favored me with a letter expressing his approbation of the views which I had published on the nature and causes of hypnotic and mesmeric phenomena. In corroboration of my views, he referred to what he had previously witnessed in oriental regions, and recommended me to look into the Dabistan, a book lately published, for additional proof to the same effect. On much recommendation I immediately sent for a copy of the Dabistan, in which I found many statements corroborative of the fact, that the eastern saints are all self-hypnotisers, adopting means essentially the same as those which I had recommended for similar purposes.
Although he rejected the transcendental/metaphysical interpretation given to these phenomena outright, Braid accepted that these accounts of Oriental practices supported his view that the effects of hypnotism could be produced in solitude, without the presence of any other person (as he had already proved to his own satisfaction with the experiments he had conducted in November 1841); and he saw correlations between many of the "metaphysical" Oriental practices and his own "rational" neuro-hypnotism, and totally rejected all of the fluid theories and magnetic practices of the mesmerists. As he later wrote:
In as much as patients can throw themselves into the nervous sleep, and manifest all the usual phenomena of Mesmerism, through their own unaided efforts, as I have so repeatedly proved by causing them to maintain a steady fixed gaze at any point, concentrating their whole mental energies on the idea of the object looked at; or that the same may arise by the patient looking at the point of his own finger, or as the Magi of Persia and Yogi of India have practised for the last 2,400 years, for religious purposes, throwing themselves into their ecstatic trances by each maintaining a steady fixed gaze at the tip of his own nose; it is obvious that there is no need for an exoteric influence to produce the phenomena of Mesmerism. [...] The great object in all these processes is to induce a habit of abstraction or concentration of attention, in which the subject is entirely absorbed with one idea, or train of ideas, whilst he is unconscious of, or indifferently conscious to, every other object, purpose, or action.

Avicenna

Avicenna (980–1037), a Persian physician, documented the characteristics of the "trance" (Hypnotic Trance) state in 1027. At that time, hypnosis as a medical treatment was seldom used; the German doctor Franz Mesmer reintroduced it in the 18th century.

Franz Mesmer

Franz Mesmer (1734–1815) believed that there is a magnetic force or "fluid" called "animal magnetism" within the universe that influences the health of the human body. He experimented with magnets to affect this field in order to produce healing. By around 1774, he had concluded that the same effect could be created by passing the hands in front of the subject's body, later referred to as making "Mesmeric passes". The word "mesmerize", formed from the last name of Franz Mesmer, was intentionally used to separate practitioners of mesmerism from the various "fluid" and "magnetic" theories included within the label "magnetism". 

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.

In writing the majority opinion, Franklin said: "This fellow Mesmer is not flowing anything from his hands that I can see. Therefore, this mesmerism must be a fraud." Mesmer left Paris and went back to Vienna to practise mesmerism. 

James Braid

Following the French committee's findings, Dugald Stewart, an influential academic philosopher of the "Scottish School of Common Sense", encouraged physicians in his Elements of the Philosophy of the Human Mind (1818) to salvage elements of Mesmerism by replacing the supernatural theory of "animal magnetism" with a new interpretation based upon "common sense" laws of physiology and psychology. Braid quotes the following passage from Stewart:
It appears to me, that the general conclusions established by Mesmer's practice, with respect to the physical effects of the principle of imagination (more particularly in cases where they co-operated together), are incomparably more curious than if he had actually demonstrated the existence of his boasted science [of "animal magnetism"]: nor can I see any good reason why a physician, who admits the efficacy of the moral [i.e., psychological] agents employed by Mesmer, should, in the exercise of his profession, scruple to copy whatever processes are necessary for subjecting them to his command, any more than that he should hesitate about employing a new physical agent, such as electricity or galvanism.
In Braid's day, the Scottish School of Common Sense provided the dominant theories of academic psychology, and Braid refers to other philosophers within this tradition throughout his writings. Braid therefore revised the theory and practice of Mesmerism and developed his own method of hypnotism as a more rational and common sense alternative.
It may here be requisite for me to explain, that by the term Hypnotism, or Nervous Sleep, which frequently occurs in the following pages, I mean a peculiar condition of the nervous system, into which it may be thrown by artificial contrivance, and which differs, in several respects, from common sleep or the waking condition. I do not allege that this condition is induced through the transmission of a magnetic or occult influence from my body into that of my patients; nor do I profess, by my processes, to produce the higher [i.e., supernatural] phenomena of the Mesmerists. My pretensions are of a much more humble character, and are all consistent with generally admitted principles in physiological and psychological science. Hypnotism might therefore not inaptly be designated, Rational Mesmerism, in contra-distinction to the Transcendental Mesmerism of the Mesmerists.
Despite briefly toying with the name "rational Mesmerism", Braid ultimately chose to emphasise the unique aspects of his approach, carrying out informal experiments throughout his career in order to refute practices that invoked supernatural forces and demonstrating instead the role of ordinary physiological and psychological processes such as suggestion and focused attention in producing the observed effects.

Braid worked very closely with his friend and ally the eminent physiologist Professor William Benjamin Carpenter, an early neuro-psychologist who introduced the "ideo-motor reflex" theory of suggestion. Carpenter had observed instances of expectation and imagination apparently influencing involuntary muscle movement. A classic example of the ideo-motor principle in action is the so-called "Chevreul pendulum" (named after Michel Eugène Chevreul). Chevreul claimed that divinatory pendulae were made to swing by unconscious muscle movements brought about by focused concentration alone.

Braid soon assimilated Carpenter's observations into his own theory, realising that the effect of focusing attention was to enhance the ideo-motor reflex response. Braid extended Carpenter's theory to encompass the influence of the mind upon the body more generally, beyond the muscular system, and therefore referred to the "ideo-dynamic" response and coined the term "psycho-physiology" to refer to the study of general mind/body interaction.

In his later works, Braid reserved the term "hypnotism" for cases in which subjects entered a state of amnesia resembling sleep. For other cases, he spoke of a "mono-ideodynamic" principle to emphasise that the eye-fixation induction technique worked by narrowing the subject's attention to a single idea or train of thought ("monoideism"), which amplified the effect of the consequent "dominant idea" upon the subject's body by means of the ideo-dynamic principle.

Hysteria vs. suggestion

For several decades Braid's work became more influential abroad than in his own country, except for a handful of followers, most notably Dr. John Milne Bramwell. The eminent neurologist Dr. George Miller Beard took Braid's theories to America. Meanwhile, his works were translated into German by William Thierry Preyer, Professor of Physiology at Jena University. The psychiatrist Albert Moll subsequently continued German research, publishing Hypnotism in 1889. France became the focal point for the study of Braid's ideas after the eminent neurologist Dr. Étienne Eugène Azam translated Braid's last manuscript (On Hypnotism, 1860) into French and presented Braid's research to the French Academy of Sciences. At the request of Azam, Paul Broca, and others, the French Academy of Science, which had investigated Mesmerism in 1784, examined Braid's writings shortly after his death.

Azam's enthusiasm for hypnotism influenced Ambroise-Auguste Liébeault, a country doctor. Hippolyte Bernheim discovered Liébeault's enormously popular group hypnotherapy clinic and subsequently became an influential hypnotist. The study of hypnotism subsequently revolved around the fierce debate between Bernheim and Jean-Martin Charcot, the two most influential figures in late 19th-century hypnotism.

Charcot operated a clinic at the Pitié-Salpêtrière Hospital (thus, known as the "Paris School" or the "Salpêtrière School"), while Bernheim had a clinic in Nancy (known as the "Nancy School"). Charcot, who was influenced more by the Mesmerists, argued that hypnotism was an abnormal state of nervous functioning found only in certain hysterical women. He claimed that it manifested in a series of physical reactions that could be divided into distinct stages. Bernheim argued that anyone could be hypnotised, that it was an extension of normal psychological functioning, and that its effects were due to suggestion. After decades of debate, Bernheim's view dominated. Charcot's theory is now just a historical curiosity.

Pierre Janet

Pierre Janet (1859–1947) reported studies on a hypnotic subject in 1882. Charcot subsequently appointed him director of the psychological laboratory at the Salpêtrière in 1889, after Janet had completed his PhD, which dealt with psychological automatism. In 1898, Janet was appointed psychology lecturer at the Sorbonne, and in 1902 he became chair of experimental and comparative psychology at the Collège de France. Janet reconciled elements of his views with those of Bernheim and his followers, developing his own sophisticated hypnotic psychotherapy based upon the concept of psychological dissociation, which, at the turn of the century, rivalled Freud's attempt to provide a more comprehensive theory of psychotherapy.

Sigmund Freud

Sigmund Freud (1856–1939), the founder of psychoanalysis, studied hypnotism at the Paris School and briefly visited the Nancy School.

At first, Freud was an enthusiastic proponent of hypnotherapy. He "initially hypnotised patients and pressed on their foreheads to help them concentrate while attempting to recover (supposedly) repressed memories", and he soon began to emphasise hypnotic regression and ab reaction (catharsis) as therapeutic methods. He wrote a favorable encyclopedia article on hypnotism, translated one of Bernheim's works into German, and published an influential series of case studies with his colleague Joseph Breuer entitled Studies on Hysteria (1895). This became the founding text of the subsequent tradition known as "hypno-analysis" or "regression hypnotherapy".

However, Freud gradually abandoned hypnotism in favour of psychoanalysis, emphasizing free association and interpretation of the unconscious. Struggling with the great expense of time that psychoanalysis required, Freud later suggested that it might be combined with hypnotic suggestion to hasten the outcome of treatment, but that this would probably weaken the outcome: "It is very probable, too, that the application of our therapy to numbers will compel us to alloy the pure gold of analysis plentifully with the copper of direct [hypnotic] suggestion."

Only a handful of Freud's followers, however, were sufficiently qualified in hypnosis to attempt the synthesis. Their work had a limited influence on the hypno-therapeutic approaches now known variously as "hypnotic regression", "hypnotic progression", and "hypnoanalysis".

Émile Coué

Émile Coué developed autosuggestion as a psychological technique.

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

Clark L. Hull

The next major development came from behavioural psychology in American university research. Clark L. Hull (1884–1952), an eminent American psychologist, published the first major compilation of laboratory studies on hypnosis, Hypnosis & Suggestibility (1933), in which he proved that hypnosis and sleep had nothing in common. Hull published many quantitative findings from hypnosis and suggestion experiments and encouraged research by mainstream psychologists. Hull's behavioural psychology interpretation of hypnosis, emphasising conditioned reflexes, rivalled the Freudian psycho-dynamic interpretation which emphasised unconscious transference.

Dave Elman

Although Dave Elman (1900–1967) was a noted radio host, comedian, and songwriter, he also made a name as a hypnotist. He led many courses for physicians, and in 1964 wrote the book Findings in Hypnosis, later to be retitled Hypnotherapy (published by Westwood Publishing). Perhaps the most well-known aspect of Elman's legacy is his method of induction, which was originally fashioned for speed work and later adapted for the use of medical professionals. 

Milton Erickson

Milton Erickson (1901–1980), the founding president of the American Society for Clinical Hypnosis and a fellow of the American Psychiatric Association, the American Psychological Association, and the American Psychopathological Association, was one of the most influential post-war hypnotherapists. He wrote several books and journal articles on the subject. During the 1960s, Erickson popularized a new branch of hypnotherapy, known as Ericksonian therapy, characterised primarily by indirect suggestion, "metaphor" (actually analogies), confusion techniques, and double binds in place of formal hypnotic inductions. However, the difference between Erickson's methods and traditional hypnotism led contemporaries such as André Weitzenhoffer to question whether he was practising "hypnosis" at all, and his approach remains in question.
Erickson had no hesitation in presenting any suggested effect as being "hypnosis", whether or not the subject was in a hypnotic state. In fact, he was not hesitant in passing off behaviour that was dubiously hypnotic as being hypnotic.
But during numerous witnessed and recorded encounters in clinical, experimental, and academic settings Erickson was able to evoke examples of classic hypnotic phenomena such as positive and negative hallucinations, anesthesia, analgesia (in childbirth and even terminal cancer patients), catalepsy, regression to provable events in subjects' early lives and even into infantile reflexology. Erickson stated in his own writings that there was no correlation between hypnotic depth and therapeutic success and that the quality of the applied psychotherapy outweighed the need for deep hypnosis in many cases. Hypnotic depth was to be pursued for research purposes.

Cognitive-behavioural

In the latter half of the 20th century, two factors contributed to the development of the cognitive-behavioural approach to hypnosis:
  1. Cognitive and behavioural theories of the nature of hypnosis (influenced by the theories of Sarbin and Barber) became increasingly influential.
  2. The therapeutic practices of hypnotherapy and various forms of cognitive behavioural therapy overlapped and influenced each other.
Although cognitive-behavioural theories of hypnosis must be distinguished from cognitive-behavioural approaches to hypnotherapy, they share similar concepts, terminology, and assumptions and have been integrated by influential researchers and clinicians such as Irving Kirsch, Steven Jay Lynn, and others.

At the outset of cognitive behavioural therapy during the 1950s, hypnosis was used by early behaviour therapists such as Joseph Wolpe and also by early cognitive therapists such as Albert Ellis. Barber, Spanos, and Chaves introduced the term "cognitive-behavioural" to describe their "nonstate" theory of hypnosis in Hypnosis, imagination, and human potentialities. However, Clark L. Hull had introduced a behavioural psychology as far back as 1933, which in turn was preceded by Ivan Pavlov. Indeed, the earliest theories and practices of hypnotism, even those of Braid, resemble the cognitive-behavioural orientation in some respects.

Applications

There are numerous applications for hypnosis across multiple fields of interest, including medical/psychotherapeutic uses, military uses, self-improvement, and entertainment. The American Medical Association currently has no official stance on the medical use of hypnosis. However, a study published in 1958 by the Council on Mental Health of the American Medical Association documented the efficacy of hypnosis in clinical settings.

Hypnosis has been used as a supplemental approach to cognitive behavioral therapy since as early as 1949. Hypnosis was defined in relation to classical conditioning; where the words of the therapist were the stimuli and the hypnosis would be the conditioned response. Some traditional cognitive behavioral therapy methods were based in classical conditioning. It would include inducing a relaxed state and introducing a feared stimuli. One way of inducing the relaxed state was through hypnosis.

Hypnotism has also been used in forensics, sports, education, physical therapy, and rehabilitation. Hypnotism has also been employed by artists for creative purposes, most notably the surrealist circle of André Breton who employed hypnosis, automatic writing, and sketches for creative purposes. Hypnotic methods have been used to re-experience drug states and mystical experiences. Self-hypnosis is popularly used to quit smoking, alleviate stress and anxiety, promote weight loss, and induce sleep hypnosis. Stage hypnosis can persuade people to perform unusual public feats.

Some people have drawn analogies between certain aspects of hypnotism and areas such as crowd psychology, religious hysteria, and ritual trances in preliterate tribal cultures.

Hypnotherapy

Hypnotherapy is a use of hypnosis in psychotherapy. It is used by licensed physicians, psychologists, and others. Physicians and psychologists may use hypnosis to treat depression, anxiety, eating disorders, sleep disorders, compulsive gambling, and posttraumatic stress, while certified hypnotherapists who are not physicians or psychologists often treat smoking and weight management. 

Hypnotherapy is viewed as a helpful adjunct by proponents, having additive effects when treating psychological disorders, such as these, along with scientifically proven cognitive therapies. Hypnotherapy should not be used for repairing or refreshing memory because hypnosis results in memory hardening, which increases the confidence in false memories. The effectiveness of hypnotherapy has not yet been accurately assessed, and, due to the lack of evidence indicating any level of efficiency, it is regarded as a type of alternative medicine by numerous reputable medical organisations, such as the NHS.

Preliminary research has expressed brief hypnosis interventions as possibly being a useful tool for managing painful HIV-DSP because of its history of usefulness in pain management, its long-term effectiveness of brief interventions, the ability to teach self-hypnosis to patients, the cost-effectiveness of the intervention, and the advantage of using such an intervention as opposed to the use of pharmaceutical drugs.

Modern hypnotherapy has been used, with varying success, in a variety of forms, such as:
  • Addictions
  • Age regression hypnotherapy (or "hypnoanalysis")
  • Cognitive-behavioural hypnotherapy, or clinical hypnosis combined with elements of cognitive behavioural therapy
  • Ericksonian hypnotherapy
  • Fears and phobias
  • Habit control
  • Pain management
  • Psychotherapy
  • Relaxation
  • Reduce patient behavior (e.g., scratching) that hinders the treatment of skin disease
  • Soothing anxious surgical patients
  • Sports performance
  • Weight loss
In a January 2001 article in Psychology Today, Harvard psychologist Deirdre Barrett wrote:
A hypnotic trance is not therapeutic in and of itself, but specific suggestions and images fed to clients in a trance can profoundly alter their behavior. As they rehearse the new ways they want to think and feel, they lay the groundwork for changes in their future actions...
Barrett described specific ways this is operationalized for habit change and amelioration of phobias. In her 1998 book of hypnotherapy case studies, she reviews the clinical research on hypnosis with dissociative disorders, smoking cessation, and insomnia, and describes successful treatments of these complaints. 

In a July 2001 article for Scientific American titled "The Truth and the Hype of Hypnosis", Michael Nash wrote that, "using hypnosis, scientists have temporarily created hallucinations, compulsions, certain types of memory loss, false memories, and delusions in the laboratory so that these phenomena can be studied in a controlled environment."

Irritable bowel syndrome

Hypnotherapy has been studied for the treatment of irritable bowel syndrome. Hypnosis for IBS has received moderate support in the National Institute for Health and Clinical Excellence guidance published for UK health services. It has been used as an aid or alternative to chemical anesthesia, and it has been studied as a way to soothe skin ailments.

Pain management

A number of studies show that hypnosis can reduce the pain experienced during burn-wound debridement, bone marrow aspirations, and childbirth. The International Journal of Clinical and Experimental Hypnosis found that hypnosis relieved the pain of 75% of 933 subjects participating in 27 different experiments.

Hypnosis is effective in decreasing the fear of cancer treatment reducing pain from and coping with cancer and other chronic conditions. Nausea and other symptoms related to incurable diseases may also be managed with hypnosis. Some practitioners have claimed hypnosis might help boost the immune system of people with cancer. However, according to the American Cancer Society, "available scientific evidence does not support the idea that hypnosis can influence the development or progression of cancer."

Hypnosis has been used as a pain relieving technique during dental surgery and related pain management regimens as well. Researchers like Jerjes and his team have reported that hypnosis can help even those patients who have acute to severe orodental pain. Additionally, Meyerson and Uziel have suggested that hypnotic methods have been found to be highly fruitful for alleviating anxiety in patients suffering from severe dental phobia.

For some psychologists who uphold the altered state theory of hypnosis, pain relief in response to hypnosis is said to be the result of the brain's dual-processing functionality. This effect is obtained either through the process of selective attention or dissociation, in which both theories involve the presence of activity in pain receptive regions of the brain, and a difference in the processing of the stimuli by the hypnotised subject.

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.

Other medical and psychotherapeutic uses

The success rate for habit control is varied. A meta-study researching hypnosis as a quit-smoking tool found it had a 20 to 30 percent success rate, while a 2007 study of patients hospitalised for cardiac and pulmonary ailments found that smokers who used hypnosis to quit smoking doubled their chances of success. In 2019, a Cochrane review was unable to find evidence of benefit of hypnosis in smoking cessation, and suggested if there is, it is small at best.

Hypnosis may be useful as an adjunct therapy for weight loss. A 1996 meta-analysis studying hypnosis combined with cognitive behavioural therapy found that people using both treatments lost more weight than people using cognitive behavioural therapy alone. The virtual gastric band procedure mixes hypnosis with hypnopedia. The hypnosis instructs the stomach that it is smaller than it really is, and hypnopedia reinforces alimentary habits. A 2016 pilot study found that there was no significant difference in effectiveness between VGB hypnotherapy and relaxation hypnotherapy.

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.

American psychiatric nurses, in most medical facilities, are allowed to administer hypnosis to patients in order to relieve symptoms such as anxiety, arousal, negative behaviours, uncontrollable behaviour, and to improve self-esteem and confidence. This is permitted only when they have been completely trained about their clinical side effects and while under supervision when administering it.

Military

A 2006 declassified 1966 document obtained by the US Freedom of Information Act archive shows that hypnosis was investigated for military applications. The full paper explores the potentials of operational uses. The overall conclusion of the study was that there was no evidence that hypnosis could be used for military applications, and no clear evidence whether "hypnosis" is a definable phenomenon outside ordinary suggestion, motivation, and subject expectancy. According to the document:
The use of hypnosis in intelligence would present certain technical problems not encountered in the clinic or laboratory. To obtain compliance from a resistant source, for example, it would be necessary to hypnotise the source under essentially hostile circumstances. There is no good evidence, clinical or experimental, that this can be done.
Furthermore, the document states that:
It would be difficult to find an area of scientific interest more beset by divided professional opinion and contradictory experimental evidence... No one can say whether hypnosis is a qualitatively unique state with some physiological and conditioned response components or only a form of suggestion induced by high motivation and a positive relationship between hypnotist and subject... T.X. Barber has produced "hypnotic deafness" and "hypnotic blindness", analgesia and other responses seen in hypnosis—all without hypnotizing anyone... Orne has shown that unhypnotized persons can be motivated to equal and surpass the supposed superhuman physical feats seen in hypnosis.
The study concluded that there are no reliable accounts of its effective use by an intelligence service in history.

Research into hypnosis in military applications is further verified by the Project MKULTRA experiments, also conducted by the CIA. According to Congressional testimony, the CIA experimented with utilizing LSD and hypnosis for mind control. Many of these programs were done domestically and on participants who were not informed of the study's purposes or that they would be given drugs.

Self-hypnosis

Self-hypnosis happens when a person hypnotises oneself, commonly involving the use of autosuggestion. The technique is often used to increase motivation for a diet, to quit smoking, or to reduce stress. People who practise self-hypnosis sometimes require assistance; some people use devices known as mind machines to assist in the process, whereas others use hypnotic recordings. 

Self-hypnosis is claimed to help with stage fright, relaxation, and physical well-being.

Stage hypnosis

Stage hypnosis is a form of entertainment, traditionally employed in a club or theatre before an audience. Due to stage hypnotists' showmanship, many people believe that hypnosis is a form of mind control. Stage hypnotists typically attempt to hypnotise the entire audience and then select individuals who are "under" to come up on stage and perform embarrassing acts, while the audience watches. However, the effects of stage hypnosis are probably due to a combination of psychological factors, participant selection, suggestibility, physical manipulation, stagecraft, and trickery. The desire to be the centre of attention, having an excuse to violate their own fear suppressors, and the pressure to please are thought to convince subjects to "play along". Books by stage hypnotists sometimes explicitly describe the use of deception in their acts; for example, Ormond McGill's New Encyclopedia of Stage Hypnosis describes an entire "fake hypnosis" act that depends upon the use of private whispers throughout. 

Music hypnosis

The idea of music as hypnosis developed from the work of Franz Mesmer. Instruments such as pianos, violins, harps and, especially, the glass harmonica often featured in Mesmer's treatments; and were considered to contribute to Mesmer's success.

Hypnotic music became an important part in the development of a 'physiological psychology' that regarded the hypnotic state as an 'automatic' phenomenon that links to physical reflex. In their experiments with sound hypnosis, Jean-Martin Charcot used gongs and tuning forks, and Ivan Pavlov used bells. The intention behind their experiments was to prove that physiological response to sound could be automatic, bypassing the conscious mind.

Music as Satanic brainwashing

In the 1980s and 1990s, a moral panic took place in the US fearing Satanic ritual abuse. As part of this, certain books such as The Devil's Disciples stated that some bands, particularly in the musical genre of heavy metal, brainwashed American teenagers with subliminal messages to lure them into the worship of the devil, sexual immorality, murder, and especially suicide. The use of satanic iconography and rhetoric in this genre provokes the parents and society, and also advocate masculine power for an audience, especially on teenagers who were ambivalent of their identity. The counteraction on heavy metal in terms of satanic brainwashing is an evidence that linked to the automatic response theories of musical hypnotism.

Crime

Various people have been suspected of or convicted for hypnosis-related crimes, including robbery and sexual abuse.

In 1951, Palle Hardrup shot and killed two people during a botched robbery in Copenhagen. Hardrup claimed that his friend and former cellmate Bjørn Schouw Nielsen had hypnotized him to commit the robbery, inadvertently causing the deaths. Both were sentenced to jail time.

In 2011, a Russian "evil hypnotist" was suspected of tricking customers in banks around Stavropol into giving away thousands of pounds worth of money. According to the local police, he would approach them and make them withdraw all of the money from their bank accounts, which they would then freely give to the man. A similar incident was reported in London in 2014, where a video seemingly showed a robber hypnotizing a shopkeeper before robbing him. The victim did nothing to stop the robber from looting his pockets and taking his cash, only calling out the thief when he was already getting away.

In 2013, the then-40-year-old amateur hypnotist Timothy Porter attempted to sexually abuse his female weight-loss client. She reported awaking from a trance and finding him behind her with his pants down, telling her to touch herself. He was subsequently called to court and included on the sex offender list. In 2015, Gary Naraido, then 52, was sentenced to 10 years in prison for several hypnosis-related sexual abuse charges. Besides the primary charge by a 22-year-old woman who he sexually abused in a hotel under the guise of a free therapy session, he also admitted to having sexually assaulted a 14-year-old girl. In December 2018, a Brazilian Medium named João Teixeira de Faria (also known as "João de Deus"), famous for performing Spiritual Surgeries through hypnosis techniques, was accused of sexual abuse by 12 women.

State versus nonstate debate

The central theoretical disagreement regarding hypnosis is known as the "state versus nonstate" debate. When Braid introduced the concept of hypnotism, he equivocated over the nature of the "state", sometimes describing it as a specific sleep-like neurological state comparable to animal hibernation or yogic meditation, while at other times he emphasised that hypnotism encompasses a number of different stages or states that are an extension of ordinary psychological and physiological processes. Overall, Braid appears to have moved from a more "special state" understanding of hypnotism toward a more complex "nonstate" orientation.

State theorists interpret the effects of hypnotism as due primarily to a specific, abnormal, and uniform psychological or physiological state of some description, often referred to as "hypnotic trance" or an "altered state of consciousness". Nonstate theorists rejected the idea of hypnotic trance and interpret the effects of hypnotism as due to a combination of multiple task-specific factors derived from normal cognitive, behavioural, and social psychology, such as social role-perception and favorable motivation (Sarbin), active imagination and positive cognitive set (Barber), response expectancy (Kirsch), and the active use of task-specific subjective strategies (Spanos). The personality psychologist Robert White is often cited as providing one of the first nonstate definitions of hypnosis in a 1941 article:
Hypnotic behaviour is meaningful, goal-directed striving, its most general goal being to behave like a hypnotised person as this is continuously defined by the operator and understood by the client.
Put simply, it is often claimed that, whereas the older "special state" interpretation emphasises the difference between hypnosis and ordinary psychological processes, the "nonstate" interpretation emphasises their similarity. 

Comparisons between hypnotised and non-hypnotised subjects suggest that, if a "hypnotic trance" does exist, it only accounts for a small proportion of the effects attributed to hypnotic suggestion, most of which can be replicated without hypnotic induction.

Hyper-suggestibility

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:
If a subject after submitting to the hypnotic procedure shows no genuine increase in susceptibility to any suggestions whatever, there seems no point in calling him hypnotised, regardless of how fully and readily he may respond to suggestions of lid-closure and other superficial sleeping behaviour.

Conditioned inhibition

Ivan Pavlov stated that hypnotic suggestion provided the best example of a conditioned reflex response in human beings; i.e., that responses to suggestions were learned associations triggered by the words used:
Speech, on account of the whole preceding life of the adult, is connected up with all the internal and external stimuli which can reach the cortex, signaling all of them and replacing all of them, and therefore it can call forth all those reactions of the organism which are normally determined by the actual stimuli themselves. We can, therefore, regard "suggestion" as the most simple form of a typical reflex in man.
He also believed that hypnosis was a "partial sleep", meaning that a generalised inhibition of cortical functioning could be encouraged to spread throughout regions of the brain. He observed that the various degrees of hypnosis did not significantly differ physiologically from the waking state and hypnosis depended on insignificant changes of environmental stimuli. Pavlov also suggested that lower-brain-stem mechanisms were involved in hypnotic conditioning.

Pavlov's ideas combined with those of his rival Vladimir Bekhterev and became the basis of hypnotic psychotherapy in the Soviet Union, as documented in the writings of his follower K.I. Platonov. Soviet theories of hypnotism subsequently influenced the writings of Western behaviourally oriented hypnotherapists such as Andrew Salter.

Neuropsychology

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. The state of light to medium hypnosis, where the body undergoes physical and mental relaxation, is associated with a pattern mostly of alpha waves 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. 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.

Another study has demonstrated that a colour hallucination suggestion given to subjects in hypnosis activated colour-processing regions of the occipital cortex. A 2004 review of research examining the EEG laboratory work in this area concludes:
Hypnosis is not a unitary state and therefore should show different patterns of EEG activity depending upon the task being experienced. In our evaluation of the literature, enhanced theta is observed during hypnosis when there is task performance or concentrative hypnosis, but not when the highly hypnotizable individuals are passively relaxed, somewhat sleepy and/or more diffuse in their attention.
Studies have shown an association of hypnosis with stronger theta-frequency activity as well as with changes to the gamma-frequency activity. Neuroimaging techniques have been used to investigate neural correlates of hypnosis.

The induction phase of hypnosis may also affect the activity in brain regions that control intention and process conflict. Anna Gosline claims:
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.

Dissociation

Pierre Janet originally developed the idea of dissociation of consciousness from his work with hysterical patients. He believed that hypnosis was an example of dissociation, whereby areas of an individual's behavioural control separate from ordinary awareness. Hypnosis would remove some control from the conscious mind, and the individual would respond with autonomic, reflexive behaviour. Weitzenhoffer describes hypnosis via this theory as "dissociation of awareness from the majority of sensory and even strictly neural events taking place."

Neodissociation

Ernest Hilgard, who developed the "neodissociation" theory of hypnotism, hypothesized that hypnosis causes the subjects to divide their consciousness voluntarily. One part responds to the hypnotist while the other retains awareness of reality. Hilgard made subjects take an ice water bath. None mentioned the water being cold or feeling pain. Hilgard then asked the subjects to lift their index finger if they felt pain and 70% of the subjects lifted their index finger. This showed that, even though the subjects were listening to the suggestive hypnotist, they still sensed the water's temperature.

Social role-taking theory

The main theorist who pioneered the influential role-taking theory of hypnotism was Theodore Sarbin. Sarbin argued that hypnotic responses were motivated attempts to fulfill the socially constructed roles of hypnotic subjects. This has led to the misconception that hypnotic subjects are simply "faking". However, Sarbin emphasised the difference between faking, in which there is little subjective identification with the role in question, and role-taking, in which the subject not only acts externally in accord with the role but also subjectively identifies with it to some degree, acting, thinking, and feeling "as if" they are hypnotised. Sarbin drew analogies between role-taking in hypnosis and role-taking in other areas such as method acting, mental illness, and shamanic possession, etc. This interpretation of hypnosis is particularly relevant to understanding stage hypnosis, in which there is clearly strong peer pressure to comply with a socially constructed role by performing accordingly on a theatrical stage.

Hence, the social constructionism and role-taking theory of hypnosis suggests that individuals are enacting (as opposed to merely playing) a role and that really there is no such thing as a hypnotic trance. A socially constructed relationship is built depending on how much rapport has been established between the "hypnotist" and the subject.

Psychologists such as Robert Baker and Graham Wagstaff claim that what we call hypnosis is actually a form of learned social behaviour, a complex hybrid of social compliance, relaxation, and suggestibility that can account for many esoteric behavioural manifestations.

Cognitive-behavioural theory

Barber, Spanos, and Chaves (1974) proposed a nonstate "cognitive-behavioural" theory of hypnosis, similar in some respects to Sarbin's social role-taking theory and building upon the earlier research of Barber. On this model, hypnosis is explained as an extension of ordinary psychological processes like imagination, relaxation, expectation, social compliance, etc. In particular, Barber argued that responses to hypnotic suggestions were mediated by a "positive cognitive set" consisting of positive expectations, attitudes, and motivation. Daniel Araoz subsequently coined the acronym "TEAM" to symbolise the subject's orientation to hypnosis in terms of "trust", "expectation", "attitude", and "motivation".

Barber et al. noted that similar factors appeared to mediate the response both to hypnotism and to cognitive behavioural therapy, in particular systematic desensitization. Hence, research and clinical practice inspired by their interpretation has led to growing interest in the relationship between hypnotherapy and cognitive behavioural therapy.

Information theory

An approach loosely based on information theory uses a brain-as-computer model. In adaptive systems, feedback increases the signal-to-noise ratio, which may converge towards a steady state. Increasing the signal-to-noise ratio enables messages to be more clearly received. The hypnotist's object is to use techniques to reduce interference and increase the receptability of specific messages (suggestions).

Systems theory

Systems theory, in this context, may be regarded as an extension of Braid's original conceptualization of hypnosis as involving "the brain and nervous system generally". Systems theory considers the nervous system's organization into interacting subsystems. Hypnotic phenomena thus involve not only increased or decreased activity of particular subsystems, but also their interaction. A central phenomenon in this regard is that of feedback loops, which suggest a mechanism for creating hypnotic phenomena.

Societies

There is a huge range of societies in England who train individuals in hypnosis; however, one of the longest-standing organisations is the British Society of Clinical and Academic Hypnosis (BSCAH). It origins date back to 1952 when a group of dentists set up the 'British Society of Dental Hypnosis'. Shortly after, a group of sympathetic medical practitioners merged with this fast-evolving organisation to form 'The Dental and Medical Society for the Study of Hypnosis'; and, in 1968, after various statutory amendments had taken place, the 'British Society of Medical and Dental Hypnosis' (BSMDH) was formed. This society always had close links with the Royal Society of Medicine and many of its members were involved in setting up a hypnosis section at this centre of medical research in London. And, in 1978, under the presidency of David Waxman, the Section of Medical and Dental Hypnosis was formed. A second society, the British Society of Experimental and Clinical Hypnosis (BSECH), was also set up a year before, in 1977, and this consisted of psychologists, doctors and dentists with an interest in hypnosis theory and practice. In 2007, the two societies merged to form the 'British Society of Clinical and Academic Hypnosis' (BSCAH). This society only trains health professionals and is interested in furthering research into clinical hypnosis.

The American Society of Clinical Hypnosis (ASCH) is unique among organizations for professionals using hypnosis because members must be licensed healthcare workers with graduate degrees. As an interdisciplinary organization, ASCH not only provides a classroom to teach professionals how to use hypnosis as a tool in their practice, it provides professionals with a community of experts from different disciplines. The ASCH's missions statement is to provide and encourage education programs to further, in every ethical way, the knowledge, understanding, and application of hypnosis in health care; to encourage research and scientific publication in the field of hypnosis; to promote the further recognition and acceptance of hypnosis as an important tool in clinical health care and focus for scientific research; to cooperate with other professional societies that share mutual goals, ethics and interests; and to provide a professional community for those clinicians and researchers who use hypnosis in their work. The ASCH also publishes the American Journal of Clinical Hypnosis

Wednesday, December 18, 2019

Closed-eye hallucination

From Wikipedia, the free encyclopedia

Closed-eye hallucinations and closed-eye visualizations (CEV) are a distinct class of hallucination. These types of hallucinations generally only occur when one's eyes are closed or when one is in a darkened room. They can be a form of phosphene. Some people report closed-eye hallucinations under the influence of psychedelics. These are reportedly of a different nature than the "open-eye" hallucinations of the same compounds. Similar hallucinations that occur due to loss of vision are called visual release hallucinations.

Levels of CEV perception

There are five known levels of CEV perception which can be achieved either through chemical stimuli or through meditative relaxation techniques. Level 1 and 2 are very common and often happen every day. It is still normal to experience level 3, and even level 4, but only a small percentage of the population does this without psychedelic drugs, meditation or extensive visualization training. 

Level 1: Visual noise

CEV noise simulation
 
The most basic form of CEV perception that can be immediately experienced in normal waking consciousness involves a seemingly random noise of pointillistic light/dark regions with no apparent shape or order. 

This can be seen when the eyes are closed and looking at the back of the eyelids. In a bright room, a dark red can be seen, owing to a small amount of light penetrating the eyelids and taking on the color of the blood it has passed through. In a dark room, blackness can be seen or the object can be more colourful. But in either case it is not a flat unchanging redness/blackness. Instead, if actively observed for a few minutes, one becomes aware of an apparent disorganized motion, a random field of lightness/darkness that overlays the redness/blackness of closed eyelids.

For a person who tries to actively observe this closed-eye perception on a regular basis, there comes a point where if they look at a flat-shaded object with their eyes wide open, and try to actively look for this visual noise, they will become aware of it and see the random pointillistic disorganized motion as if it were a translucent overlay on top of what is actually being seen by their open eyes.

When seen overlaid onto the physical world, this CEV noise does not obscure physical vision at all, and in fact is hard to notice if the visual field is highly patterned, complex, or in motion. When active observation is stopped, it is not obvious or noticeable, and seemingly disappears from normal physical perception. Individuals suffering from visual snow see similar noise but experience difficulty blocking it from conscious perception. 

Level 2: Light/dark flashes

Some mental control can be exerted over these closed-eye visualizations, but it usually requires a bit of relaxation and concentration to achieve. When properly relaxed it is possible to cause regions of intense black, bright white or even colors such as yellow, green, or pink to appear in the noise. These regions can span the entire visual field, but seem to be fleeting in nature.

Level 3: Patterns, motion, and color

This level is relatively easily accessible to people who use psychedelic drugs such as LSD. However, it is also accessible to people involved in deep concentration for long periods of time. When lying down at night and closing the eyes, right before sleep or just before waking up, the complex motion of these patterns can become directly visible without any great effort thanks to hypnagogic hallucination. The patterns themselves might resemble fractals.

Level 4: Objects and things

This is a fairly deep state. At this level, thoughts visually manifest as objects or environments. When this level is reached, the CEV noise seems to calm down and fade away, leaving behind an intense flat ordered blackness. The visual field becomes a sort of active space. A side component of this is the ability to feel motion when the eyes are closed.

Opening the eyes returns one to the normal physical world, but still with the CEV object field overlaid onto it and present. In this state it is possible to see things that appear to be physical objects in the open-eye physical world, but that aren't really there.

Level 5: Overriding physical perception

This level can be entered from complete sensory deprivation, as experienced in an isolation tank, but even there it requires great relaxation.

According to lucid dreaming researcher Stephen LaBerge, perceptions can come from either the senses or imagination. An inhibitory system involving the thalamus, likely involving serotonergic neurons, inhibits imaginary perceptions from becoming too activated so they turn into hallucinations. This system is inhibited during REM sleep, and the imagination can freely run into the perceptual systems. What happens at level 5 is likely that this system is inhibited, just like in REM sleep, by different causes like sensory deprivation, psychedelic drugs or meditative relaxation techniques.

What is not a CEV


Image burn-in (afterimage)

Image burn-in occurs when very bright objects lie in one's field of vision, and should not be confused with closed-eye hallucinations. Visual burn-in from bright lights is visible for a few minutes after closing the eyes, or by blinking repeatedly, but the burn-in effect slowly fades away as the retina recovers, whereas the waking-consciousness CEV noise will not disappear if observed continuously over a period of time.

Corneal liquid

CEV does not involve the liquid and air bubbles on the surface of the cornea, which can also be seen by extremely nearsighted people when looking at bright point-light sources with glasses/contacts removed. Also called "floaters", they often appear as cells floating across the eye. Full-closing and reopening the eyelids creates a very definite wiper-ridge in the corneal liquid that is readily visible. Fully closing and reopening the eyelids also stirs up the corneal liquid which settles down after a brief moment. The motion of waking-consciousness CEV noise is not so directly and physically controllable and repeatable. This is not necessarily only associated with extreme nearsightedness.

Blue-sky sprites

CEV does not seem to be related to the "sprites" (blue field entoptic phenomenon) that can be seen as dots darting around when staring up into a bright blue sky on a sunny day (not looking at the sun). These dots superimposed over a flat blue background are white blood cells moving through the blood vessels of the retina. The motion of waking-consciousness CEV noise is uniformly random compared to the waking-consciousness blue-sky sprite motion. 

Physical retinal stimulation

CEV is unrelated to the visual noise seen when the retina is physically stimulated. The retina can be made to produce light patterns of visual noise simply by one rubbing their eyes somewhat forcefully in a manner that increases intraocular pressure. Additionally, retinal noise can be produced by touching near the rear of the eyeball producing pressure phosphenes (for example, if one closes one's eyes, looks all the way left, and lightly touches the rightmost part of the eye socket, this produces visual noise in the shape of a circle that appears at the left side of the visual field – a practice that is neither painful nor dangerous). None of these are closed-eye hallucinations.

Hallucinogen

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Hallucinogen
 
A hallucinogen is a psychoactive agent which most likely causes hallucinations, perceptual anomalies, and other substantial subjective changes in thoughts, emotion, and consciousness. The common types of hallucinogens are psychedelics, dissociatives and deliriants. Although hallucinations are a common symptom of amphetamine psychosis, amphetamines are not considered hallucinogens as they are not a primary effect of the drugs themselves. While hallucinations can occur when abusing stimulants, the nature of stimulant psychosis is not unlike delirium. 

Nomenclature

A debate persists on criteria which would easily differentiate a substance which is 'psychedelic' from one 'hallucinogenic'. Sir Thomas Browne in 1646 coined the term 'hallucination' from the Latin word "alucinari" meaning "to wander in the mind".

A 'hallucinogen' and a 'psychedelic' may refer correctly to the same substance. Psychedelics are considered by many to be the 'traditional' or 'classical hallucinogens'. A 'hallucinogen' in this sense broadly refers to any substance which causes changes in perception or hallucinations, while psychedelics also carry a connotation of psychedelic culture

Psychedelics (classical hallucinogens)

One "Blotter" sheet of 900 LSD doses.
 
The word psychedelic (From Ancient Greek ψυχή (psychê) mind, soul + δηλος (dêlos) manifest, reveal + -ic) was coined to express the idea of a drug that makes manifest a hidden but real aspect of the mind. It is commonly applied to any drug with perception-altering effects such as LSD and other ergotamine derivatives, DMT and other tryptamines including the alkaloids of Psilocybe spp., mescaline and other phenethylamines.

The classical hallucinogens are considered to be the representative psychedelics and LSD is generally considered the prototypical psychedelic. In order to refer to the LSD-like psychedelics, scientific authors have used the term "classical hallucinogen" in the sense defined by Glennon (1999): "The classical hallucinogens are agents that meet Hollister's original definition, but are also agents that: (a) bind at 5-HT2 serotonin receptors, and (b) are recognized by animals trained to discriminate 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) from vehicle. Otherwise, when the term 'psychedelic' is used to refer only to the LSD-like psychedelics (a.k.a. the classical hallucinogens), authors explicitly point that they intend 'psychedelic' to be understood according to this more restrictive interpretation (e.g. see Nichols, 2004).

One explanatory model for the experiences provoked by psychedelics is the "reducing valve" concept, first articulated in Aldous Huxley's book The Doors of Perception. In this view, the drugs disable the brain's "filtering" ability to selectively prevent certain perceptions, emotions, memories and thoughts from ever reaching the conscious mind. This effect has been described as mind expanding, or consciousness expanding, for the drug "expands" the realm of experience available to conscious awareness. 

While possessing a unique mechanism of action, cannabis or marijuana has historically been regarded alongside the classic psychedelics.

Research chemicals and designer drugs

A designer drug is a structural or functional analog of a controlled substance that has been designed to mimic the pharmacological effects of the original drug while at the same time avoid being classified as illegal (by specification as a research chemical) and/or avoid detection in standard drug tests. Many designer drugs and research chemicals are hallucinogenic in nature, such as those in the 2C and 25-NB (NBOMe) families.

Dissociatives

Dissociatives produce analgesia, amnesia and catalepsy at anesthetic doses. They also produce a sense of detachment from the surrounding environment, hence "the state has been designated as dissociative anesthesia since the patient truly seems disassociated from his environment." Dissociative symptoms include the disruption or compartmentalization of "...the usually integrated functions of consciousness, memory, identity or perception." Dissociation of sensory input can cause derealization, the perception of the outside world as being dream-like, vague or unreal. Other dissociative experiences include depersonalization, which includes feeling dissociated from one's personality; feeling unreal; feeling able to observe one's actions but not actively take control; being unable to associate with one's self in the mirror while maintaining rational awareness that the image in the mirror is the same person. Simeon (2004) offered "...common descriptions of depersonalisation experiences: watching oneself from a distance (similar to watching a movie); candid out-of-body experiences; a sense of just going through the motions; one part of the self acting/participating while the other part is observing;...."

The classical dissociatives achieve their effect through blocking the signals received by the NMDA receptor set (NMDA receptor antagonism) and include ketamine, methoxetamine (MXE), phencyclidine (PCP), dextromethorphan (DXM), and nitrous oxide. However, dissociation is also remarkably administered by salvinorin A's (the active constituent in Salvia divinorum shown to the left) potent κ-opioid receptor agonism, though sometimes described as an atypical psychedelic.

Some dissociatives can have CNS depressant effects, thereby carrying similar risks as opioids, which can slow breathing or heart rate to levels resulting in death (when using very high doses). DXM in higher doses can increase heart rate and blood pressure and still depress respiration. Inversely, PCP can have more unpredictable effects and has often been classified as a stimulant and a depressant in some texts along with being as a dissociative. While many have reported that they "feel no pain" while under the effects of PCP, DXM and Ketamine, this does not fall under the usual classification of anesthetics in recreational doses (anesthetic doses of DXM may be dangerous). Rather, true to their name, they process pain as a kind of "far away" sensation; pain, although present, becomes a disembodied experience and there is much less emotion associated with it. As for probably the most common dissociative, nitrous oxide, the principal risk seems to be due to oxygen deprivation. Injury from falling is also a danger, as nitrous oxide may cause sudden loss of consciousness, an effect of oxygen deprivation. Because of the high level of physical activity and relative imperviousness to pain induced by PCP, some deaths have been reported due to the release of myoglobin from ruptured muscle cells. High amounts of myoglobin can induce renal shutdown.

Many users of dissociatives have been concerned about the possibility of NMDA antagonist neurotoxicity (NAN). This concern is partly due to William E. White, the author of the DXM FAQ, who claimed that dissociatives definitely cause brain damage. The argument was criticized on the basis of lack of evidence and White retracted his claim. White's claims and the ensuing criticism surrounded original research by John Olney

In 1989, John Olney discovered that neuronal vacuolation and other cytotoxic changes ("lesions") occurred in brains of rats administered NMDA antagonists, including PCP and ketamine. Repeated doses of NMDA antagonists led to cellular tolerance and hence continuous exposure to NMDA antagonists did not lead to cumulative neurotoxic effects. Antihistamines such as diphenhydramine, barbiturates and even diazepam have been found to prevent NAN. LSD and DOB have also been found to prevent NAN.

Deliriants

Datura innoxia in flower.
 
Attractive but highly toxic berry of Atropa belladonna
 
Flowers and foliage of Nicotiana tabacum, the cultivated tobacco.
 
Single fruiting body of Amanita muscaria
 
Myristica fragrans fruit, halved, showing within the brown seed (nutmeg) enclosed in its red aril (mace).
 
Deliriants, as their name implies, induce a state of delirium in the user, characterized by extreme confusion and an inability to control one's actions. They are called deliriants because their subjective effects are similar to the experiences of people with delirious fevers. The term was introduced by David F. Duncan and Robert S. Gold to distinguish these drugs from psychedelics and dissociatives, such as LSD and ketamine respectively, due to their primary effect of causing delirium, as opposed to the more lucid states produced by the other hallucinogens.

Despite the fully legal status of several common deliriant plants, deliriants are largely unpopular as recreational drugs due to the severe, generally unpleasant and often dangerous nature of the hallucinations produced.

Typical or classical deliriants are those which block the muscarinic acetylcholine receptors (antagonism). These are said to be anticholinergic. Many of these compounds are produced naturally by plant genera belonging to the nightshade family Solanaceae, such as Datura, Brugmansia and Latua in the New World and Atropa, Hyoscyamus and Mandragora in the Old World. These tropane alkaloids are poisonous and can cause death due to tachycardia-induced heart failure and hyperthermia even in small doses. Additionally, over-the-counter antihistamines such as diphenhydramine (brand name Benadryl) and dimenhydrinate (brand name Dramamine) also have an anticholinergic effect.

Uncured tobacco is also a deliriant due to its intoxicatingly high levels of nicotine.

The fly agaric mushroom, Amanita muscaria, is often informally lumped with the nightshade plants as a deliriant, though regarded as a dissociative with some regularity as well. This may be explained by the familiarity of both A. muscaria and Atropa belladonna to European culture, their formal statuses as deadly poisons, and their generally undesirable, unpleasant, and dangerous nature, with the potential for death from physical and behavioral toxicity a possibility even when dosages are carefully considered. 

Nutmeg has deliriant and hallucinogenic effects as well due to some of its psychoactive chemicals, such as myristicin, which may be anticholinergic like the tropane alkaloids of the nightshade plants, or as suggested by Alexander Shulgin, partially metabolized into the empathogen-entactogen MMDA.

History of use

Psychedelics, dissociatives, and deliriants have a long history of use within medicinal and religious traditions around the world including shamanic forms of ritual healing and divination, initiation rites, and rituals of syncretistic movements such as União do Vegetal, Santo Daime, and the Native American Church

In the context of religious practice, psychedelic drug use, as well as other substances such as tobacco (hypnotic), are referred to as entheogens. In some places peyote is classified as 'sacrament' for part of religious ceremonies, and is legally condoned for such use.

Hallucinogenic substances are among the oldest drugs used by human kind, as hallucinogenic substances naturally occur in mushrooms, cacti and a variety of other plants. Numerous cultures worldwide have endorsed the use of hallucinogens in medicine, religion and recreation, to varying extents, while some cultures have regulated or outright prohibited their use. In most developed countries today, the possession of many hallucinogens, even those found commonly in nature, is considered a crime punishable by fines, imprisonment or even death. In some countries, such as the United States and the Netherlands, partial deference may be granted to traditional religious use by members of indigenous ethnic minorities such as the Native American Church and the Santo Daime Church. Recently the União do Vegetal, a Christian-based religious sect whose composition is not primarily ethnicity-based, won a United States Supreme Court decision authorizing its use of ayahuasca. However, in Brazil, ayahuasca use in a religious context has been legal since 1987. In fact, it is a common belief among members of the União do Vegetal that ayahuasca presents no risk for adolescents within the church, as long as they take it within a religious context.

Traditional religious and shamanic use

Historically, hallucinogens have been commonly used in religious or shamanic rituals. In this context they are referred to as entheogens, and are used to facilitate healing, divination, communication with spirits, and coming-of-age ceremonies. Evidence exists for the use of entheogens in prehistoric times, as well as in numerous ancient cultures, including Ancient Egyptian, Mycenaean, Ancient Greek, Vedic, Maya, Inca and Aztec cultures. The Upper Amazon is home to the strongest extant entheogenic tradition; the Urarina of the Peruvian Amazon, for instance, continue to practice an elaborate system of ayahuasca shamanism, coupled with an animistic belief system.

Shamans consume hallucinogenic substances in order to induce a trance. Once in this trance, shamans believe that they are able to communicate with the spirit world, and can see what is causing their patients' illness. The Aguaruna of Peru believe that many illnesses are caused by the darts of sorcerers. Under the influence of yaji, a hallucinogenic drink, Aguaruna shamans try to discover and remove the darts from their patients.

Concerning lycanthropy (werewolves) and the use of hallucinogenic drugs, Frida G. Surawicz and Richard Banta wrote "In the first case, this was brought on by LSD and strychnine and continued casual marijuana use... Concerning drugs as causative agents, it is interesting to note that opium has been mentioned in a dual capacity, namely as a drug which can cause lycanthropy as well as a drug for its treatment."

Early scientific investigations

Although natural hallucinogenic drugs have been known to mankind for millennia, it was not until the early 20th century that they received extensive attention from Western science. Earlier beginnings include scientific studies of nitrous oxide in the late 18th century, and initial studies of the constituents of the peyote cactus in the late 19th century. Starting in 1927 with Kurt Beringer's Der Meskalinrausch (The Mescaline Intoxication), more intensive effort began to be focused on studies of psychoactive plants. Around the same time, Louis Lewin published his extensive survey of psychoactive plants, Phantastica (1928). Important developments in the years that followed included the re-discovery of Mexican psilocybin mushrooms (in 1936 by Robert J. Weitlaner) and Christmas vine (in 1939 by Richard Evans Schultes). Arguably the most important pre-World War II development was by Albert Hofmann's 1938 discovery of the semi-synthetic drug LSD, which was later discovered to produce hallucinogenic effects in 1943.

Hallucinogens after World War II

After World War II there was an explosion of interest in hallucinogenic drugs in psychiatry, owing mainly to the invention of LSD. Interest in the drugs tended to focus on either the potential for psychotherapeutic applications of the drugs (see psychedelic psychotherapy), or on the use of hallucinogens to produce a "controlled psychosis", in order to understand psychotic disorders such as schizophrenia. By 1951, more than 100 articles on LSD had appeared in medical journals, and by 1961, the number had increased to more than 1000 articles. Hallucinogens were also researched in several countries for their potential as agents of chemical warfare. Most famously, several incidents associated with the CIA's MK-ULTRA mind control research project have been the topic of media attention and lawsuits.

At the beginning of the 1950s, the existence of hallucinogenic drugs was virtually unknown to the general public in the West. However this soon changed as several influential figures were introduced to the hallucinogenic experience. Aldous Huxley's 1953 essay The Doors of Perception, describing his experiences with mescaline, and R. Gordon Wasson's 1957 Life magazine article (Seeking the Magic Mushroom) brought the topic into the public limelight. In the early 1960s, counterculture icons such as Jerry Garcia, Timothy Leary, Allen Ginsberg and Ken Kesey advocated the drugs for their psychedelic effects, and a large subculture of psychedelic drug users was spawned. Psychedelic drugs played a major role in catalyzing the vast social changes initiated in the 1960s. As a result of the growing popularity of LSD and disdain for the hippies with whom it was heavily associated, LSD was banned in the United States in 1967. This greatly reduced the clinical research about LSD, although limited experiments continued to take place, such as those conducted by Reese Jones in San Francisco.

As early as the 1960s, research into the medicinal properties of LSD was being conducted. It has been found that LSD is a fairly effective treatment for mental disorders such as obsessive compulsive disorder (OCD). "Savage et al. (1962) provided the earliest report of efficacy for a hallucinogen in OCD, where after two doses of LSD, a patient who suffered from depression and violent obsessive sexual thoughts experienced dramatic and permanent improvement (Nichols 2004: 164)." 

Starting in the mid-20th century, psychedelic drugs has been the object of extensive attention in the Western world. They have been and are being explored as potential therapeutic agents in treating depression, posttraumatic stress disorder, obsessive–compulsive disorder, alcoholism, drug addiction, cluster headaches, and other ailments. Early military research focused on their use as incapacitating agents. Intelligence agencies tested these drugs in the hope that they would provide an effective means of interrogation, with little success. 

Yet the most popular, and at the same time most stigmatized, use of psychedelics in Western culture has been associated with the search for direct religious experience, enhanced creativity, personal development, and "mind expansion". The use of psychedelic drugs was a major element of the 1960s counterculture, where it became associated with various social movements and a general atmosphere of rebellion and strife between generations.

Despite prohibition, the recreational, spiritual, and medical use of psychedelics continues today. Organizations, such as MAPS and the Heffter Research Institute, have arisen to foster research into their safety and efficacy, while advocacy groups such as the Center for Cognitive Liberty and Ethics push for their legalization. In addition to this activity by proponents, hallucinogens are also widely used in basic science research to understand the mind and brain. However, ever since hallucinogenic experimentation was discontinued in the late 1960s, research into the therapeutic applications of such drugs have been almost nonexistent, that is until this last decade where research has finally been allowed to resume. 

Legal status and attitudes

In Canada, mescaline is listed as prohibited under schedule III of the Controlled Drugs and Substances Acts, but peyote is specifically exempt and legally available.

As of 2008, most well-known hallucinogens (aside from dextromethorphan, diphenhydramine and dimenhydrinate) are illegal in most Western countries. In the United States hallucinogens are classified as a schedule 1 drug. The 3-pronged test for schedule 1 drugs is as follows: the drug has no currently accepted medical use, there is a lack of safety for the use of the drug under medical supervision, and the substance has a high potential for abuse. One notable exception to the current criminalization trend is in parts of Western Europe, especially in the Netherlands, where cannabis is considered to be a "soft drug". Previously included were hallucinogenic mushrooms, but as of October 2007 the Netherlands officials have moved to ban their sale following several widely publicized incidents involving tourists. While the possession of soft drugs is technically illegal, the Dutch government has decided that using law enforcement to combat their use is largely a waste of resources. As a result, public "coffeeshops" in the Netherlands openly sell cannabis for personal use, and "smart shops" sell drugs like Salvia divinorum, and until the ban of psilocybin mushrooms took effect, they were still available for purchase in smartshops as well.

Despite being scheduled as a controlled substance in the mid-1980s, MDMA's popularity has been growing since that time in western Europe and in the United States.

Attitudes towards hallucinogens other than cannabis have been slower to change. Several attempts to change the law on the grounds of freedom of religion have been made. Some of these have been successful, for example the Native American Church in the United States, and Santo Daime in Brazil. Some people argue that a religious setting should not be necessary for the legitimacy of hallucinogenic drug use, and for this reason also criticize the euphemistic use of the term "entheogen". Non-religious reasons for the use of hallucinogens including spiritual, introspective, psychotherapeutic, recreational and even hedonistic motives, each subject to some degree of social disapproval, have all been defended as the legitimate exercising of civil liberties and freedom of thought.

Several medical and scientific experts, including the late Albert Hofmann, advocate the drugs should not be banned, but should be strongly regulated and warn they can be dangerous without proper psychological supervision.

Psychedelics and mental illnesses in long-term users

Most psychedelics are not known to have long-term physical toxicity. However, entactogens such as MDMA that release neurotransmitters may stimulate increased formation of free radicals possibly formed from neurotransmitters released from the synaptic vesicle. Free radicals are associated with cell damage in other contexts, and have been suggested to be involved in many types of mental conditions including Parkinson's disease, senility, schizophrenia, and Alzheimer's. Research on this question has not reached a firm conclusion. The same concerns do not apply to psychedelics that do not release neurotransmitters, such as LSD, nor to dissociatives or deliriants.

No clear connection has been made between psychedelic drugs and organic brain damage. However, hallucinogen persisting perception disorder (HPPD) is a diagnosed condition wherein certain visual effects of drugs persist for a long time, sometimes permanently, although science and medicine have yet to determine what causes the condition. 

A large epidemiological study in the U.S. found that other than personality disorders and other substance use disorders, lifetime hallucinogen use was not associated with other mental disorders, and that risk of developing a hallucinogen use disorder was very low.

How hallucinogens affect the brain

LSD, mescaline, psilocybin, and PCP are drugs that cause hallucinations, which can alter a person's perception of reality. LSD, mescaline, and psilocybin cause their effects by initially disrupting the interaction of nerve cells and the neurotransmitter serotonin. It is distributed throughout the brain and spinal cord, where the serotonin system is involved with controlling of the behavioral, perceptual, and regulatory systems. This also includes mood, hunger, body temperature, sexual behavior, muscle control, and sensory perception. Certain hallucinogens, such as PCP, act through a glutamate receptor in the brain which is important for perception of pain, responses to the environment, and learning and memory. Thus far, there have been no properly controlled research studies on the specific effects of these drugs on the human brain, but smaller studies have shown some of the documented effects associated with the use of hallucinogens.

Naming and taxonomy


Psychedelic nomenclature

The class of drugs described in this article has been described by a profusion of names, most of which are associated with a particular theory of their nature. 

Louis Lewin started out in 1928 by using the word phantastica as the title of his ground-breaking monograph about plants that, in his words, "bring about evident cerebral excitation in the form of hallucinations, illusions and visions [...] followed by unconsciousness or other symptoms of altered cerebral functioning". But no sooner had the term been invented, or Lewin complained that the word "does not cover all that I should wish it to convey", and indeed with the proliferation of research following the discovery of LSD came numerous attempts to improve on it, such as hallucinogen, phanerothyme, psychedelic, psychotomimetic, psychogenic, schizophrenogenic, cataleptogenic, mysticomimetic, psychodysleptic, and entheogenic.

The word psychotomimetic, meaning "mimicking psychosis", reflects the hypothesis of early researchers that the effects of psychedelic drugs are similar to naturally occurring symptoms of schizophrenia, though it has since been discovered that some psychedelics resemble endogenous psychoses better than others. PCP and ketamine are known to better resemble endogenous psychoses because they reproduce both positive and negative symptoms of psychoses, while psilocybin and related hallucinogens typically produce effects resembling only the positive symptoms of schizophrenia. While the serotonergic psychedelics (LSD, psilocybin, mescaline, etc.) do produce subjective effects distinct from NMDA antagonist dissociatives (PCP, ketamine, dextrorphan), there is obvious overlap in the mental processes that these drugs affect and research has discovered that there is overlap in the mechanisms by which both types of psychedelics mimic psychotic symptoms. One double-blind study examining the differences between DMT and ketamine hypothesized that classically psychedelic drugs most resemble paranoid schizophrenia while dissociative drugs best mimicked catatonic subtypes or otherwise undifferentiated schizophrenia. The researchers expressed the view that "a heterogeneous disorder like schizophrenia is unlikely to be modeled accurately by a single pharmacological agent." 

The word psychedelic was coined by Humphrey Osmond and has the rather mysterious but at least somewhat value-neutral meaning of "mind manifesting". The word entheogen, on the other hand, which is often used to describe the religious and ritual use of psychedelic drugs in anthropological studies, is associated with the idea that it could be relevant to religion. The words entactogen, empathogen, dissociative and deliriant, at last, have all been coined to refer to classes of drugs similar to the classical psychedelics that seemed deserving of a name of their own.
Many different names have been proposed over the years for this drug class. The famous German toxicologist Louis Lewin used the name phantastica earlier in this century, and as we shall see later, such a descriptor is not so farfetched. The most popular names—hallucinogen, psychotomimetic, and psychedelic ("mind manifesting")—have often been used interchangeably. Hallucinogen is now, however, the most common designation in the scientific literature, although it is an inaccurate descriptor of the actual effects of these drugs. In the lay press, the term psychedelic is still the most popular and has held sway for nearly four decades. Most recently, there has been a movement in nonscientific circles to recognize the ability of these substances to provoke mystical experiences and evoke feelings of spiritual significance. Thus, the term entheogen, derived from the Greek word entheos, which means "god within", was introduced by Ruck et al. and has seen increasing use. This term suggests that these substances reveal or allow a connection to the "divine within". Although it seems unlikely that this name will ever be accepted in formal scientific circles, its use has dramatically increased in the popular media and on internet sites. Indeed, in much of the counterculture that uses these substances, entheogen has replaced psychedelic as the name of choice and we may expect to see this trend continue.

Taxonomy

Hallucinogens can be classified by their subjective effects, mechanisms of action, and chemical structure. These classifications often correlate to some extent. In this article, they are classified as psychedelics, dissociatives, and deliriants, preferably entirely to the exclusion of the inaccurate word hallucinogen, but the reader is well advised to consider that this particular classification is not universally accepted. The taxonomy used here attempts to blend these three approaches in order to provide as clear and accessible an overview as possible.

Almost all hallucinogens contain nitrogen and are therefore classified as alkaloids. THC and salvinorin A are exceptions. Many hallucinogens have chemical structures similar to those of human neurotransmitters, such as serotonin, and temporarily modify the action of neurotransmitters and/or receptor sites. 

Leo Hollister's five criteria for establishing that a drug is hallucinogenic are as follows:
(1) in proportion to other effects, changes in thought, perception, and mood should predominate; (2) intellectual or memory impairment should be minimal; (3) stupor, narcosis, or excessive stimulation should not be an integral effect; (4) autonomic nervous system side effects should be minimal; and (5) addictive craving should be absent.

Lewin's classes

A classical classification, mainly of historical interest, is that of Lewin (Phantastica, 1928):
Class I Phantastica roughly correspond to the psychedelics, which is a more modern term usually used as synonym to "hallucinogen" by people with positive attitudes towards them. Here the term is used a bit differently to discriminate one particular class of hallucinogens which it seems to describe best. They typically have no sedative effects (sometimes the opposite) and there is usually a clearcut memory to their effects. These drugs have also been referred to as the "classical" hallucinogens.
Class II Phantastica correspond to the other classes in our scheme. They tend to sedate in addition to their hallucinogenic properties and there often is an impaired memory trace after the effects wear off.

Pharmacological classes of hallucinogens

One possible way of classifying the hallucinogens is by their chemical structure and that of the receptors they act on. In this vein, the following categories are often used:
Problems with structure-based frameworks is that the same structural motif can include a wide variety of drugs which have substantially different effects. For example, both methamphetamine and MDMA are substituted amphetamines, but methamphetamine has a much stronger stimulant action than MDMA, with none of the latter's empathogenic effects. Also, drugs commonly act on more than one receptor; DXM, for instance, is primarily dissociative in high doses, but also acts as a serotonin reuptake inhibitor, similar to many phenethylamines.

Even so, in many cases structure-based frameworks are still very useful, and the identification of a biologically active pharmacophore and synthesis of analogues of known active substances remains an integral part of modern medicinal chemistry.

Operator (computer programming)

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