Psychedelics, dissociatives and deliriants
Encyclopedia
This general group of pharmacological
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...

 agents can be divided into three broad categories: psychedelic
Psychedelic drug
A psychedelic substance is a psychoactive drug whose primary action is to alter cognition and perception. Psychedelics are part of a wider class of psychoactive drugs known as hallucinogens, a class that also includes related substances such as dissociatives and deliriants...

s
, dissociatives, and deliriant
Deliriant
The deliriants are a special class of acetylcholine-inhibitor hallucinogen. The term was introduced by David F. Duncan and Robert S...

s
. These classes of psychoactive drugs have in common that they can cause subjective changes in perception
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...

, thought
Thought
"Thought" generally refers to any mental or intellectual activity involving an individual's subjective consciousness. It can refer either to the act of thinking or the resulting ideas or arrangements of ideas. Similar concepts include cognition, sentience, consciousness, and imagination...

, emotion
Emotion
Emotion is a complex psychophysiological experience of an individual's state of mind as interacting with biochemical and environmental influences. In humans, emotion fundamentally involves "physiological arousal, expressive behaviors, and conscious experience." Emotion is associated with mood,...

 and consciousness
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

. Unlike other psychoactive drug
Psychoactive drug
A psychoactive drug, psychopharmaceutical, or psychotropic is a chemical substance that crosses the blood–brain barrier and acts primarily upon the central nervous system where it affects brain function, resulting in changes in perception, mood, consciousness, cognition, and behavior...

s, such as stimulants and opioids, these drugs do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness. These experiences are often compared to non-ordinary forms of consciousness such as trance
Trance
Trance denotes a variety of processes, ecstasy, techniques, modalities and states of mind, awareness and consciousness. Trance states may occur involuntarily and unbidden.The term trance may be associated with meditation, magic, flow, and prayer...

, meditation
Meditation
Meditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....

, and dreams.

Hollister's criteria for establishing that a drug is hallucinogenic is:
  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.


Not all drugs produce the same effect and even the same drug can produce different effects in the same individual on different occasions.

Nature of the drugs

The term "hallucinogen" is a misnomer because these drugs do not cause hallucination
Hallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...

s at typical doses. Hallucinations, strictly speaking, are perceptions that have no basis in reality, but that appear entirely realistic. A typical "hallucination" induced by a psychedelic drug is more accurately described as a modification of regular perception, and the subject is usually quite aware of the illusory and personal nature of their perceptions. Deliriants, such as diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...

 and atropine
Atropine
Atropine is a naturally occurring tropane alkaloid extracted from deadly nightshade , Jimson weed , mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects...

, may cause hallucinations in the proper sense.

Psychedelics, dissociatives, and deliriants have a long history of use within medicinal and religious traditions around the world. They are used in shamanic forms of ritual healing
Healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....

 and divination
Divination
Divination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...

, in initiation rites, and in the religious rituals of syncretistic movements such as União do Vegetal
União do Vegetal
União do Vegetal is a Christian religion based on the use of Hoasca in a program of spiritual evolution based on mental concentration and the search for self-knowledge...

, Santo Daime
Santo Daime
Santo Daime is a syncretic spiritual practice founded in the 1930s in the Brazilian Amazonian state of Acre by Raimundo Irineu Serra, known as Mestre Irineu...

, and the Native American Church
Native American Church
Native American Church, a religious denomination which practices Peyotism or the Peyote religion, originated in the U.S. state of Oklahoma, and is the most widespread indigenous religion among Native Americans in the United States...

.
When used in religious practice, psychedelic drugs, as well as other substances like tobacco
Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...

, are referred to as entheogens. Also, in some states and on some reservations, certain drugs like Peyote
Peyote
Lophophora williamsii , better known by its common name Peyote , is a small, spineless cactus with psychoactive alkaloids, particularly mescaline.It is native to southwestern Texas and Mexico...

 are classified as part of a recognized religious ceremony, and if used in said ceremonies, are considered legal. 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 in Canada.

Starting in the mid-20th century, psychedelic drugs have been the object of extensive attention in the Western world. They have been and are being explored as potential therapeutic agents in treating depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

, Post-traumatic Stress Disorder
Post-traumatic stress disorder
Posttraumaticstress disorder is a severe anxiety disorder that can develop after exposure to any event that results in psychological trauma. This event may involve the threat of death to oneself or to someone else, or to one's own or someone else's physical, sexual, or psychological integrity,...

, Obsessive-compulsive Disorder
Obsessive-compulsive disorder
Obsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...

, alcoholism
Alcoholism
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...

, opioid
Opioid
An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

 addiction
Addiction
Historically, addiction has been defined as physical and psychological dependence on psychoactive substances which cross the blood-brain barrier once ingested, temporarily altering the chemical milieu of the brain.Addiction can also be viewed as a continued involvement with a substance or activity...

, (of which the last two are being tested to be treatable with dextromethorphan hydrobromide AKA DXM, a dissociative listed below), cluster headache
Cluster headache
Cluster headache, nicknamed "suicide headache", is a neurological disease that involves, as its most prominent feature, an immense degree of pain in the head. Cluster headaches occur periodically: spontaneous remissions interrupt active periods of pain. The cause of the disease is currently unknown...

s, 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
Interrogation
Interrogation is interviewing as commonly employed by officers of the police, military, and Intelligence agencies with the goal of extracting a confession or obtaining information. Subjects of interrogation are often the suspects, victims, or witnesses of a crime...

, 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
Religious experience
Religious experience is a subjective experience in which an individual reports contact with a transcendent reality, an encounter or union with the divine....

, enhanced creativity
Creativity
Creativity refers to the phenomenon whereby a person creates something new that has some kind of value. What counts as "new" may be in reference to the individual creator, or to the society or domain within which the novelty occurs...

, personal development, and "mind expansion". The use of psychedelic drugs was a major element of the 1960s counterculture
Counterculture
Counterculture is a sociological term used to describe the values and norms of behavior of a cultural group, or subculture, that run counter to those of the social mainstream of the day, the cultural equivalent of political opposition. Counterculture can also be described as a group whose behavior...

, where bawsaq 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 Multidisciplinary Association for Psychedelic Studies
Multidisciplinary Association for Psychedelic Studies
The Multidisciplinary Association for Psychedelic Studies is a membership-based 501 non-profit research and educational organization working to develop psychedelics and marijuana into legal prescription drugs...

 and the Heffter Research Institute
Heffter Research Institute
The Heffter Research Institute was incorporated in New Mexico in 1993 as a non-profit organization to support and promote investigation into the medical uses of psychedelic hallucinogens...

, 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. In some cases, this includes research in humans, like that conducted by Roland Griffiths and colleagues.

Psychedelics (classical hallucinogens)

The word psychedelic (From Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean 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
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...

, psilocybin
Psilocybin
Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...

, DMT
Dimethyltryptamine
N,N-Dimethyltryptamine is a naturally occurring psychedelic compound of the tryptamine family. DMT is found in several plants, and also in trace amounts in humans and other mammals, where it is originally derived from the essential amino acid tryptophan, and ultimately produced by the enzyme INMT...

, 2C-B
2C-B
2C-B or 4-bromo-2,5-dimethoxyphenethylamine is a psychedelic drug of the 2C family. It was first synthesized by Alexander Shulgin in 1974. In Shulgin's book PiHKAL, the dosage range is listed as 16–24 mg. 2C-B is sold as a white powder sometimes pressed in tablets or gel caps and is referred...

, mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....

 and DOB
2,5-Dimethoxy-4-bromoamphetamine
DOB, also known as Brolamfetamine and Bromo-DMA, is a psychedelic hallucinogenic drug and a substituted amphetamine of the phenethylamine class of compounds, which can be used as an entheogen. DOB was first synthesized by Alexander Shulgin in 1967...

 as well as a panoply of other tryptamines, phenethylamines and yet more exotic chemicals.

The term "psychedelic" is used interchangeably with "psychotomimetic" and "hallucinogen", thus it can refer to a large number of drugs such as classical hallucinogens (LSD
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...

, psilocybin
Psilocybin
Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...

, mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....

, etc.), entactogens (e.g. MDMA), cannabinoids
Cannabinoids
Cannabinoids are a class of chemical compounds that include the phytocannabinoids , and chemical compounds that mimic the actions of phytocannabinoids or have a similar structure...

 and dissociative drugs (e.g. ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...

). 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).

Common herbal and fungal sources of psychedelics include psilocybe
Psilocybe
Psilocybe is a genus of small mushrooms growing worldwide. This genus is best known for its species with psychedelic or hallucinogenic properties, widely known as "magic mushrooms", though the majority of species do not contain hallucinogenic compounds...

 mushrooms (largely psilocybe cubensis
Psilocybe cubensis
Psilocybe cubensis is a species of psychedelic mushroom whose principal active compounds are psilocybin and psilocin. Commonly called Boomers, Cubes or Gold Caps, it belongs to the Strophariaceae family of fungi and was previously known as Stropharia cubensis.-Taxonomy and naming:The species was...

), various ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

 preparations, peyote
Peyote
Lophophora williamsii , better known by its common name Peyote , is a small, spineless cactus with psychoactive alkaloids, particularly mescaline.It is native to southwestern Texas and Mexico...

, Peruvian Torch, and San Pedro cactus.

One explanatory model for the experiences provoked by hallucinogens is the "reducing valve" concept, first articulated in Aldous Huxley
Aldous Huxley
Aldous Leonard Huxley was an English writer and one of the most prominent members of the famous Huxley family. Best known for his novels including Brave New World and a wide-ranging output of essays, Huxley also edited the magazine Oxford Poetry, and published short stories, poetry, travel...

's book The Doors of Perception
The Doors of Perception
The Doors of Perception is a 1954 book by Aldous Huxley detailing his experiences when taking mescaline. The book takes the form of Huxley’s recollection of a mescaline trip which took place over the course of an afternoon, and takes its title from William Blake's poem The Marriage of Heaven and Hell...

. 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.

Psychedelic effects can vary depending on the precise drug and dosage, as well as the set and setting
Set and setting
Set and setting describes the context for psychoactive and particularly psychedelic drug experiences: one's mindset and the setting in which the user has the experience. This is especially relevant for psychedelic or hallucinogenic experiences...

. "Trips" range between the short but intense effects of intravenous DMT
Dimethyltryptamine
N,N-Dimethyltryptamine is a naturally occurring psychedelic compound of the tryptamine family. DMT is found in several plants, and also in trace amounts in humans and other mammals, where it is originally derived from the essential amino acid tryptophan, and ultimately produced by the enzyme INMT...

 to the protracted ibogaine
Ibogaine
Ibogaine is a naturally occurring psychoactive substance found in a number of plants, principally in a member of the Apocynaceae family known as Iboga . A hallucinogen with both psychedelic and dissociative properties, the substance is banned in some countries; in other countries it is being used...

 experience, which can last for days. Appropriate dosage ranges from extremely low (LSD
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...

) to rather high (mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....

). Some drugs, like the auditory hallucinogen DiPT, act specifically to distort a single sense, and others have more diffuse effects on cognition generally. Some are more conducive to solitary experiences, while others are positively empathogenic
Empathogen-entactogen
The terms empathogen and entactogen are used to describe a class of psychoactive drugs that produce distinctive emotional and social effects similar to those of MDMA. Putative members of this class include 2C-B, 2C-I, MDMA, MDA, MDEA, MBDB, 2C-T-7, and 2C-T-2, among others...

.

Though the natural drugs have a long history of use and usually have an extensive study profile aside from the mortality rates of the drugs, in recent times there has been large production of hundreds of virtually unstudied psychedelics (JWH-018
JWH-018
JWH-018 or AM-678 is an analgesic chemical from the naphthoylindole family, which acts as a full agonist at both the CB1 and CB2 cannabinoid receptors, with some selectivity for CB2...

, CP 47,497
CP 47,497
CP 47,497 is a cannabinoid receptor agonist drug, developed by Pfizer in the 1980s. It has analgesic effects and is used in scientific research...

, DPT
DPT
The abbreviation DPT can refer to:*The Democratic Party of Turkmenistan*The Diphtheria-Pertussis-Tetanus vaccine*The Democratic Peace Theory*Dioptre, most commonly a unit measuring refraction in a lens or curved mirror...

, TFMPP, 2C-T-7
2C-T-7
2C-T-7 is a psychedelic phenethylamine of the 2C family. In his book PiHKAL: A Chemical Love Story, Alexander Shulgin lists the dosage range as 10 to 30 mg. 2C-T-7 is generally taken orally, and produces psychedelic and entactogenic effects that last 8 to 15 hours...

, 2C-H
2C-H
2C-H, or 2,5-dimethoxyphenethylamine, is a lesser-known chemical of the 2C family. 2C-H was first synthesized by Alexander Shulgin. In his book PiHKAL , the dosage and duration are both unknown...

, Methylone, N-Methyl-N-isopropyltryptamine
N-Methyl-N-isopropyltryptamine
N-Methyl-N-isopropyltryptamine is a psychedelic tryptamine, closely related to DMT, DIPT and Miprocin.-Chemistry:MiPT base, unlike many other tryptamines in their freebase form, does not decompose rapidly in the presence of light in oxygen....

 (MIPT), and AL-LAD
AL-LAD
AL-LAD, also known as 6-allyl-6-nor-lysergic acid diethylamide, is a hallucinogenic drug and an analogue of LSD. It is described by Alexander Shulgin in the book TiHKAL ...

 to name a few) that may be potentially harmful. This is especially the case with the designer drugs in the psychedelic-amphetamine class. Because of this factor, one should not make the generalization that all psychedelics can not be potentially harmful at normal doses.

Dissociatives

Dissociative drugs 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."p. 523 Dissociation of sensory input can cause derealization
Derealization
Derealization is an alteration in the perception or experience of the external world so that it seems unreal. Other symptoms include feeling as though one's environment is lacking in spontaneity, emotional coloring and depth. It is a dissociative symptom of many conditions, such as psychiatric and...

, the perception of the outside world as being dream-like or unreal. Other dissociative experiences include depersonalization
Depersonalization
Depersonalization is an anomaly of the mechanism by which an individual has self-awareness. It is a feeling of watching oneself act, while having no control over a situation. Sufferers feel they have changed, and the world has become less real, vague, dreamlike, or lacking in significance...

, which includes feeling detached from one's body; feeling unreal; feeling able to observe one's actions but not actively take control; being unable to recognize 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 primary dissociatives are similar in action to PCP
Phencyclidine
Phencyclidine , commonly initialized as PCP and known colloquially as angel dust, is a recreational dissociative drug...

 (NMDA receptor antagonism
NMDA receptor antagonist
NMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the N-methyl d-aspartate receptor . They are used as anesthesia for animals and, less commonly, for humans; the state of anesthesia they induce is referred to as dissociative anesthesia...

) and include ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...

 (an anesthetic), dextromethorphan
Dextromethorphan
Dextromethorphan is an antitussive drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, and others, including generic labels. Dextromethorphan has also found other uses in medicine, ranging...

 and nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...

. Dissociation is remarkably administered by salvinorin A
Salvinorin A
Salvinorin A is the main active psychotropic molecule in Salvia divinorum, a Mexican plant which has a long history of use as an entheogen by indigenous Mazatec shamans...

's (from the Salvia divinorum
Salvia divinorum
Salvia divinorum is a psychoactive plant which can induce dissociative effects and is a potent producer of "visions" and other hallucinatory experiences...

 plant shown to the left) potent κ-Opioid receptor agonism (dissociation characteristically comes through NMDA antagonism), which is notably the most potent psychoactive chemical harnessed directly from the plant kingdom. Effects from salvinorin A have been infamously documented on youtube and typically last from 15 minutes to 1 hour depending on the route of administration (inhalation and "quidding," respectively).

Some dissociatives can have CNS
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

 depressant
Depressant
A depressant, or central depressant, is a drug or endogenous compound that depresses the function or activity of a specific part of the brain...

 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, N2O, the principal risk seems to be due to oxygen deprivation
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

. 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
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 shutdown. Along with most, if not all of the chemicals in this article, none of the dissociatives have any physically addictive properties, though psychological addiction has been observed.

Many users of dissociatives have been concerned about the possibility of [NMDA antagonist neurotoxicity] (NAN). This concern is partly due to White (1998), 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 (2004) retracted his claim. White's claims and the ensuing criticism surrounded original research by Olney et al. (1989).

In 1989, Olney et al. discovered that neuronal vacuolation and other cytotoxic changes ("lesions") occurred in brains of rats administered NMDA antagonists, including PCP, MK-801 [dizocilpine] 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

The deliriants (or anticholinergic
Anticholinergic
An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicycloverine, and the classic example is atropine....

s) are a special class of dissociative which are antagonists for the acetylcholine receptor
Acetylcholine receptor
An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

s (unlike muscarine
Muscarine
Muscarine, L--muscarine, or muscarin is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly C. dealbata. Mushrooms in the genera Entoloma and Mycena have also been found to contain levels of muscarine which can be dangerous if ingested...

 and nicotine
Nicotine
Nicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...

 which are agonist
Agonist
An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

s of these receptors). Deliriants are sometimes called true hallucinogens, because they do cause hallucinations in the proper sense: a user may have conversations with people who aren't there, or become angry at a 'person' mimicking their actions, not realizing it is their own reflection in a mirror. They are called deliriants because their effects are similar to the experiences of people with delirious fevers. While dissociatives
Dissociative drug
Dissociatives are a class of psychoactive drugs which are said to reduce or block signals to the conscious mind from other parts of the brain...

 can produce effects similar to lucid dreaming
Lucid dreaming
A lucid dream is a dream in which one is aware that one is dreaming. The term was coined by the Dutch psychiatrist and writer Frederik van Eeden . In a lucid dream, the dreamer can actively participate in and manipulate imaginary experiences in the dream environment. Lucid dreams can seem real and...

 (during which one is consciously aware of dreaming), the deliriants have effects akin to sleepwalking
Sleepwalking
Sleepwalking, also known as somnambulism, is a sleep disorder belonging to the parasomnia family. Sleepwalkers arise from the slow wave sleep stage in a state of low consciousness and perform activities that are usually performed during a state of full consciousness...

 (during which one does not remember the experience).

Included in this group are such plants as deadly nightshade, mandrake
Mandrake (plant)
Mandrake is the common name for members of the plant genus Mandragora, particularly the species Mandragora officinarum, belonging to the nightshades family...

, henbane
Henbane
Henbane , also known as stinking nightshade or black henbane, is a plant of the family Solanaceae that originated in Eurasia, though it is now globally distributed.-Toxicity and historical usage:...

 and datura
Datura
Datura is a genus of nine species of vespertine flowering plants belonging to the family Solanaceae. Its precise and natural distribution is uncertain, owing to its extensive cultivation and naturalization throughout the temperate and tropical regions of the globe...

 and fungi such as Amanita muscaria
Amanita muscaria
Amanita muscaria, commonly known as the fly agaric or fly amanita , is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita...

, as well as a number of pharmaceutical drugs, when taken in very high doses, such as the first-generation antihistamines diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...

 (Benadryl), its close relative dimenhydrinate
Dimenhydrinate
Dimenhydrinate is an over-the-counter drug used to prevent nausea and motion sickness...

 (Dramamine or Gravol) and hydroxyzine
Hydroxyzine
Hydroxyzine is a first-generation antihistamine of the diphenylmethane and piperazine classes. It was first synthesized by Union Chimique Belge in 1956 and was marketed by Pfizer in the United States later the same year, and is still in widespread use today....

, to name a few. Certain Native American traditions also involve the consumption of massive amounts of tobacco
Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...

 during religious ceremonies in order to experience the plant's deliriant effects.

In addition to the dangers of being far more disconnected from reality than with other drugs and retaining a truly fragmented dissociation from regular consciousness without being immobilized, the anticholinergics are toxic, carry the risk of death by overdose, and also include a number of uncomfortable side effects. These side effects usually include dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

 and mydriasis
Mydriasis
Mydriasis is a dilation of the pupil due to disease, trauma or the use of drugs. Normally, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day...

 (dilation of the pupils).

Most modern-day psychonauts who use deliriants report similar or identical hallucinations and challenges. For example, diphenhydramine, as well as dimenhydrinate, when taken in a high enough dosage, often are reported to evoke vivid, dark, and entity-like hallucinations, peripheral disturbances, feelings of being alone but simultaneously of being watched, and hallucinations of real things ceasing to exist. Deliriants also may cause confusion or even rage, and thus have been used by ancient peoples as a stimulant before going into battle.

History of use

Hallucinogenic substances are among the oldest drugs used by human kind, as hallucinogenic substances naturally occur in mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...

s, cacti
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...

 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
Crime
Crime is the breach of rules or laws for which some governing authority can ultimately prescribe a conviction...

 punishable by fines, imprisonment or even death
Capital punishment
Capital punishment, the death penalty, or execution is the sentence of death upon a person by the state as a punishment for an offence. Crimes that can result in a death penalty are known as capital crimes or capital offences. The term capital originates from the Latin capitalis, literally...

. In some countries, such as the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, partial deference may be granted to traditional religious use by members of indigenous
Indigenous peoples
Indigenous peoples are ethnic groups that are defined as indigenous according to one of the various definitions of the term, there is no universally accepted definition but most of which carry connotations of being the "original inhabitants" of a territory....

 ethnic minorities such as the Native American Church
Native American Church
Native American Church, a religious denomination which practices Peyotism or the Peyote religion, originated in the U.S. state of Oklahoma, and is the most widespread indigenous religion among Native Americans in the United States...

 and the Santo Daime
Santo Daime
Santo Daime is a syncretic spiritual practice founded in the 1930s in the Brazilian Amazonian state of Acre by Raimundo Irineu Serra, known as Mestre Irineu...

 Church. Recently the União do Vegetal
União do Vegetal
União do Vegetal is a Christian religion based on the use of Hoasca in a program of spiritual evolution based on mental concentration and the search for self-knowledge...

, a Christian
Christian
A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

-based religious sect whose composition is not primarily ethnicity-based, won a United States Supreme Court decision authorizing its use of ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

. However, in Brazil, ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

 use in a religious context has been legal since 1987. In fact, it is a common belief among members of the União do Vegetal
União do Vegetal
União do Vegetal is a Christian religion based on the use of Hoasca in a program of spiritual evolution based on mental concentration and the search for self-knowledge...

 that ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

 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 most commonly used in religious or shamanic
Shamanism
Shamanism is an anthropological term referencing a range of beliefs and practices regarding communication with the spiritual world. To quote Eliade: "A first definition of this complex phenomenon, and perhaps the least hazardous, will be: shamanism = technique of ecstasy." Shamanism encompasses the...

 ritual
Ritual
A ritual is a set of actions, performed mainly for their symbolic value. It may be prescribed by a religion or by the traditions of a community. The term usually excludes actions which are arbitrarily chosen by the performers....

s. In this context they are referred to as entheogens, and they are used to facilitate healing, divination, communication with spirits, and coming-of-age ceremonies. Evidence exists for the use of entheogens in prehistoric
Prehistory
Prehistory is the span of time before recorded history. Prehistory can refer to the period of human existence before the availability of those written records with which recorded history begins. More broadly, it refers to all the time preceding human existence and the invention of writing...

 times, as well as in numerous ancient cultures, including the Rus'
Kievan Rus'
Kievan Rus was a medieval polity in Eastern Europe, from the late 9th to the mid 13th century, when it disintegrated under the pressure of the Mongol invasion of 1237–1240....

, Ancient Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

ian, Mycenaean, Ancient Greek, Vedic, Maya
Maya civilization
The Maya is a Mesoamerican civilization, noted for the only known fully developed written language of the pre-Columbian Americas, as well as for its art, architecture, and mathematical and astronomical systems. Initially established during the Pre-Classic period The Maya is a Mesoamerican...

, Inca and Aztec
Aztec
The Aztec people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the late post-classic period in Mesoamerican chronology.Aztec is the...

 cultures. The Upper Amazon is home to the strongest extant entheogenic tradition; the Urarina
Urarina
The Urarina are an indigenous people of the Peruvian Amazon Basin who inhabit the Chambira, Urituyacu, and Corrientes Rivers. According to both archaeological and historical sources, they have resided in the Chambira Basin of contemporary northeastern Peru for centuries. The Urarina refer to...

 of Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

vian Amazonia, for instance, continue to practice an elaborate system of ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

 shamanism
Shamanism
Shamanism is an anthropological term referencing a range of beliefs and practices regarding communication with the spiritual world. To quote Eliade: "A first definition of this complex phenomenon, and perhaps the least hazardous, will be: shamanism = technique of ecstasy." Shamanism encompasses the...

, coupled with an animistic belief system.
Shamans consume hallucinogenic substances in order to induce a trance. Once in this trance, shamans are able to communicate with the spirit world, and can often 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 are able to discover and remove darts from their patients.

The Rise of the Abrahamic religions (Judaism
Judaism
Judaism ) is the "religion, philosophy, and way of life" of the Jewish people...

, Christianity
Christianity
Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

 and Islam
Islam
Islam . The most common are and .   : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...

) caused a decline of entheogen
Entheogen
An entheogen , in the strict sense, is a psychoactive substance used in a religious, shamanic, or spiritual context. Historically, entheogens were mostly derived from plant sources and have been used in a variety of traditional religious contexts...

ic use of hallucinogens use in its wake, as the authority of scripture and the priesthood gradually reduced the role granted to direct spiritual experience, especially by the laity . Examples of this development include the destruction of the Eleusinian Mysteries
Eleusinian Mysteries
The Eleusinian Mysteries were initiation ceremonies held every year for the cult of Demeter and Persephone based at Eleusis in ancient Greece. Of all the mysteries celebrated in ancient times, these were held to be the ones of greatest importance...

, which are now widely assumed to have involved entheogenic rituals, and the Great Witch Hunt of the Early Modern Age, in which practitioners of the weird drug rites in Western Europe were accused of associating with the devil
Devil
The Devil is believed in many religions and cultures to be a powerful, supernatural entity that is the personification of evil and the enemy of God and humankind. The nature of the role varies greatly...

. The Spanish conquistadores associated local entheogenic traditions of South America with heresy and satanism, and uprooted many of them, but nevertheless, some cultures there and elsewhere have kept their traditions alive to this day.

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
Western world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...

 science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

. Earlier beginnings include scientific studies of nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...

 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
Louis Lewin
Louis Lewin was a German pharmacologist. In 1886, he published the first methodical analysis of the Peyote cactus, which was originally named in his honor Anhalonium lewinii.He received his education at the gymnasium and the University of Berlin...

 published his extensive survey of psychoactive plants, Phantastica (1928). Important developments in the years that followed included the re-discovery of Mexican
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 magic mushrooms
Psychedelic mushroom
Psilocybin mushrooms are fungi that contain the psychoactive compounds psilocybin and psilocin. There are multiple colloquial terms for psilocybin mushrooms, the most common being shrooms or magic mushrooms....

 (in 1936 by Robert J. Weitlaner) and ololiuhqui (in 1939 by Richard Evans Schultes
Richard Evans Schultes
Richard Evans Schultes may be considered the father of modern ethnobotany, for his studies of indigenous peoples' uses of plants, including especially entheogenic or hallucinogenic plants , for his lifelong collaborations with chemists, and...

). Arguably the most important pre-World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 development was by Albert Hofmann
Albert Hofmann
Albert Hofmann was a Swiss scientist known best for being the first person to synthesize, ingest and learn of the psychedelic effects of lysergic acid diethylamide . He authored more than 100 scientific articles and a number of books, including LSD: My Problem Child...

's 1938 discovery of the semi-synthetic
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

 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
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...

, owing mainly to the invention of LSD. Interest in the drugs tended to focus on either the potential for psychotherapeutic
Psychotherapy
Psychotherapy is a general term referring to any form of therapeutic interaction or treatment contracted between a trained professional and a client or patient; family, couple or group...

 applications of the drugs (see psychedelic psychotherapy
Psychedelic psychotherapy
Psychedelic therapy refers to therapeutic practices involving the use of psychedelic drugs, particularly serotonergic psychedelics such as ergine, LSD, psilocin and DMT...

), or on the use of hallucinogens to produce a "controlled psychosis
Psychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

", in order to understand psychotic disorders such as schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

. 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
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...

. Most famously, several incidents associated with the CIA
Central Intelligence Agency
The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

's MK-ULTRA mind control
Mind control
Mind control refers to a process in which a group or individual "systematically uses unethically manipulative methods to persuade others to conform to the wishes of the manipulator, often to the detriment of the person being manipulated"...

 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 among the general public of the West
Western world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...

. However this soon changed as several influential figures were introduced to the hallucinogenic experience. Aldous Huxley
Aldous Huxley
Aldous Leonard Huxley was an English writer and one of the most prominent members of the famous Huxley family. Best known for his novels including Brave New World and a wide-ranging output of essays, Huxley also edited the magazine Oxford Poetry, and published short stories, poetry, travel...

's 1953 essay The Doors of Perception
The Doors of Perception
The Doors of Perception is a 1954 book by Aldous Huxley detailing his experiences when taking mescaline. The book takes the form of Huxley’s recollection of a mescaline trip which took place over the course of an afternoon, and takes its title from William Blake's poem The Marriage of Heaven and Hell...

, describing his experiences with mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....

, 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
Counterculture
Counterculture is a sociological term used to describe the values and norms of behavior of a cultural group, or subculture, that run counter to those of the social mainstream of the day, the cultural equivalent of political opposition. Counterculture can also be described as a group whose behavior...

 icons such as Jerry Garcia
Jerry Garcia
Jerome John "Jerry" Garcia was an American musician best known for his lead guitar work, singing and songwriting with the band the Grateful Dead...

, Timothy Leary
Timothy Leary
Timothy Francis Leary was an American psychologist and writer, known for his advocacy of psychedelic drugs. During a time when drugs like LSD and psilocybin were legal, Leary conducted experiments at Harvard University under the Harvard Psilocybin Project, resulting in the Concord Prison...

, Allen Ginsberg
Allen Ginsberg
Irwin Allen Ginsberg was an American poet and one of the leading figures of the Beat Generation in the 1950s. He vigorously opposed militarism, materialism and sexual repression...

 and Ken Kesey
Ken Kesey
Kenneth Elton "Ken" Kesey was an American author, best known for his novel One Flew Over the Cuckoo's Nest , and as a counter-cultural figure who considered himself a link between the Beat Generation of the 1950s and the hippies of the 1960s. "I was too young to be a beatnik, and too old to be a...

 advocated the drugs for their psychedelic
Psychedelic
The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...

 effects, and a large subculture
Subculture
In sociology, anthropology and cultural studies, a subculture is a group of people with a culture which differentiates them from the larger culture to which they belong.- Definition :...

 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 hippie
Hippie
The hippie subculture was originally a youth movement that arose in the United States during the mid-1960s and spread to other countries around the world. The etymology of the term 'hippie' is from hipster, and was initially used to describe beatniks who had moved into San Francisco's...

s with whom it was heavily associated, LSD was banned in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 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 1960's, 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)." LSD, along with other hallucinogens, possesses a considerable amount of medicinal properties, which is why further research on the medical uses of hallucinogens is paramount.

Legal status and attitudes

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
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...

, especially in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, 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 ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

, Salvia Divinorum
Salvia divinorum
Salvia divinorum is a psychoactive plant which can induce dissociative effects and is a potent producer of "visions" and other hallucinatory experiences...

 and until the ban of magic mushrooms took effect, they were still available for purchase in smartshops as well. (See Drug policy of the Netherlands
Drug policy of the Netherlands
The drug policy of the Netherlands officially has four major objectives:# To prevent recreational drug use and to treat and rehabilitate recreational drug users.# To reduce harm to users....

).

Despite being scheduled as a controlled substance in the mid 1980s, ecstasy's popularity has been growing since that time in western Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Attitudes towards hallucinogens other than cannabis have been slower to change. Several attempts to change the law on the grounds of freedom of religion
Freedom of religion
Freedom of religion is a principle that supports the freedom of an individual or community, in public or private, to manifest religion or belief in teaching, practice, worship, and observance; the concept is generally recognized also to include the freedom to change religion or not to follow any...

 have been made. Some of these have been successful, for example the Native American Church
Native American Church
Native American Church, a religious denomination which practices Peyotism or the Peyote religion, originated in the U.S. state of Oklahoma, and is the most widespread indigenous religion among Native Americans in the United States...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and Santo Daime
Santo Daime
Santo Daime is a syncretic spiritual practice founded in the 1930s in the Brazilian Amazonian state of Acre by Raimundo Irineu Serra, known as Mestre Irineu...

 in Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. 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
Spirituality
Spirituality can refer to an ultimate or an alleged immaterial reality; an inner path enabling a person to discover the essence of his/her being; or the “deepest values and meanings by which people live.” Spiritual practices, including meditation, prayer and contemplation, are intended to develop...

, introspective
Introspection
Introspection is the self-observation and reporting of conscious inner thoughts, desires and sensations. It is a conscious and purposive process relying on thinking, reasoning, and examining one's own thoughts, feelings, and, in more spiritual cases, one's soul...

, psychotherapeutic
Psychotherapy
Psychotherapy is a general term referring to any form of therapeutic interaction or treatment contracted between a trained professional and a client or patient; family, couple or group...

, recreational and even hedonistic
Hedonism
Hedonism is a school of thought which argues that pleasure is the only intrinsic good. In very simple terms, a hedonist strives to maximize net pleasure .-Etymology:The name derives from the Greek word for "delight" ....

 motives, each subject to some degree of social disapproval, have all been defended as the legitimate exercising of civil liberties
Civil liberties
Civil liberties are rights and freedoms that provide an individual specific rights such as the freedom from slavery and forced labour, freedom from torture and death, the right to liberty and security, right to a fair trial, the right to defend one's self, the right to own and bear arms, the right...

, including freedom of thought
Freedom of thought
Freedom of thought is the freedom of an individual to hold or consider a fact, viewpoint, or thought, independent of others' viewpoints....

 and freedom of self-harm.

Some people connect the idea of being "high" or going through a psychedelic
Psychedelic
The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...

 state, as having brain damage
Brain damage
"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...

 or going crazy. This is due to the effect of the drug which, in some cases, can be overwhelming. Effects of these drugs may mimic psychological conditions such as psychosis
Psychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

, schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

, and thought disorder
Thought disorder
In psychiatry, thought disorder or formal thought disorder is a term used to describe incomprehensible language, either speech or writing, that is presumed to reflect thinking. There are different types...

, but there have not yet been studies confirming any real similarities between these different states of mind.

Several medical and scientific experts, including the late Albert Hofmann
Albert Hofmann
Albert Hofmann was a Swiss scientist known best for being the first person to synthesize, ingest and learn of the psychedelic effects of lysergic acid diethylamide . He authored more than 100 scientific articles and a number of books, including LSD: My Problem Child...

, 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
Synaptic vesicle
In a neuron, synaptic vesicles store various neurotransmitters that are released at the synapse. The release is regulated by a voltage-dependent calcium channel. Vesicles are essential for propagating nerve impulses between neurons and are constantly recreated by the cell...

. 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
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...

, senility, schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

, 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
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...

, nor to dissociatives or deliriants.

No clear connection has been made between psychedelic drugs and organic brain damage. However, hallucinogen persisting perception disorder
Hallucinogen persisting perception disorder
Hallucinogen persisting perception disorder is a disorder characterized by a continual presence of visual disturbances that are reminiscent of those generated by the ingestion of hallucinogenic substances. Previous use of hallucinogens by the person is needed, though not sufficient, for...

 (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.

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
Louis Lewin
Louis Lewin was a German pharmacologist. In 1886, he published the first methodical analysis of the Peyote cactus, which was originally named in his honor Anhalonium lewinii.He received his education at the gymnasium and the University of Berlin...

 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
Psychedelic
The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...

, psychotomimetic
Psychotomimetic
A drug with psychotomimetic actions mimics the symptoms of psychosis, including delusions and/or delirium, as opposed to just hallucinations. Some drugs of the opioid class have psychotomimetic effects, such as pentazocine and butorphanol....

, psycholytic, schizophrenogenic, cataleptogenic, mysticomimetic, psychodysleptic, and entheogenic.

The word psychotomimetic, meaning "mimicking psychosis
Psychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

", 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
DMT
DMT may refer to:In chemical substances:* Dimethyltryptamine, a psychedelic tryptamine* Dimethyl terephthalate, a polyester precursor* Desoxymethyltestosterone, a designer anabolic steroid...

 and ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...

 hypothesized that LSD-like drugs most resemble paranoid schizophrenia while PCP-like 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.

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 psychedelic
Psychedelic
The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...

s, dissociatives, and deliriant
Deliriant
The deliriants are a special class of acetylcholine-inhibitor hallucinogen. The term was introduced by David F. Duncan and Robert S...

s, 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
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 and are therefore classified as alkaloids. THC
Tetrahydrocannabinol
Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...

 and Salvinorin A
Salvinorin A
Salvinorin A is the main active psychotropic molecule in Salvia divinorum, a Mexican plant which has a long history of use as an entheogen by indigenous Mazatec shamans...

 are exceptions. Many hallucinogens have chemical structures similar to those of human neurotransmitters, such as serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

, and temporarily modify the action of neurotransmitters and/or receptor sites.

Lewin's classes

A classical classification, mainly of historical interest, is that of Lewin (Phantastica, 1928):
Class I Phantastica roughly correspond to the psychedelics
Psychedelic drug
A psychedelic substance is a psychoactive drug whose primary action is to alter cognition and perception. Psychedelics are part of a wider class of psychoactive drugs known as hallucinogens, a class that also includes related substances such as dissociatives and deliriants...

, 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:
  • Psychedelics
    Psychedelic drug
    A psychedelic substance is a psychoactive drug whose primary action is to alter cognition and perception. Psychedelics are part of a wider class of psychoactive drugs known as hallucinogens, a class that also includes related substances such as dissociatives and deliriants...

     (5-HT2A receptor
    5-HT2A receptor
    The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...

     agonists)
    • Tryptamine
      Tryptamine
      Tryptamine is a monoamine alkaloid found in plants, fungi, and animals. It is based around the indole ring structure, and is chemically related to the amino acid tryptophan, from which its name is derived...

      s
    • Phenethylamine
      Phenethylamine
      Phenylethylamine or phenethylamine is a natural monoamine alkaloid, trace amine, and also the name of a class of chemicals with many members well known for psychoactive drug and stimulant effects. Studies suggest that phenylethylamine functions as a neuromodulator or neurotransmitter in the...

      s
  • Cannabinoids
    Cannabinoids
    Cannabinoids are a class of chemical compounds that include the phytocannabinoids , and chemical compounds that mimic the actions of phytocannabinoids or have a similar structure...

     (CB-1 receptor agonists)
  • Dissociatives
    Dissociative drug
    Dissociatives are a class of psychoactive drugs which are said to reduce or block signals to the conscious mind from other parts of the brain...

    • NMDA receptor antagonist
      NMDA receptor antagonist
      NMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the N-methyl d-aspartate receptor . They are used as anesthesia for animals and, less commonly, for humans; the state of anesthesia they induce is referred to as dissociative anesthesia...

      s
    • κ-Opioid receptor agonists
  • Deliriant
    Deliriant
    The deliriants are a special class of acetylcholine-inhibitor hallucinogen. The term was introduced by David F. Duncan and Robert S...

    s


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
Methamphetamine
Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...

 and ecstasy are substituted amphetamines, but methamphetamine has a much stronger stimulant action than ecstasy, with none of the latter's empathogenic effects. Also, drugs commonly act on more than one receptor; DXM
Dextromethorphan
Dextromethorphan is an antitussive drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, and others, including generic labels. Dextromethorphan has also found other uses in medicine, ranging...

, for instance, is primarily dissociative in high doses, but also acts as a serotonin reuptake inhibitor, similar to many phenethylamines and in fact, the phenethylamine moiety is embedded in the structure of DXM. LSD also contains both the indole backbone and the phenethylamine moiety.

Even so, in many cases structure-based frameworks are still very useful, and the identification of a biologically active pharmacophore
Pharmacophore
thumb|right|300px|An example of a pharmacophore model.A pharmacophore is an abstract description of molecular features which are necessary for molecular recognition of a ligand by a biological macromolecule....

 and synthesis of analogues of known active substances remains an integral part of modern medicinal chemistry
Medicinal chemistry
Medicinal chemistry and pharmaceutical chemistry are disciplines at the intersection of chemistry, especially synthetic organic chemistry, and pharmacology and various other biological specialties, where it is involved with design, chemical synthesis and development for market of pharmaceutical...

.

Hallucinogenic organisms

The following is a list of some organisms known to contain hallucinogens
  • Plants
    • Psychedelics
      • Ayahuasca
        Ayahuasca
        Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

         (contains DMT
        Dimethyltryptamine
        N,N-Dimethyltryptamine is a naturally occurring psychedelic compound of the tryptamine family. DMT is found in several plants, and also in trace amounts in humans and other mammals, where it is originally derived from the essential amino acid tryptophan, and ultimately produced by the enzyme INMT...

         and an MAOI, commonly Banisteriopsis caapi
        Banisteriopsis caapi
        Banisteriopsis caapi, also known as Ayahuasca, Caapi or Yage, is a South American jungle vine of the family Malpighiaceae. It is used to prepare Ayahuasca, a decoction that has a long history of entheogenic uses as a medicine and "plant teacher" among the indigenous peoples of the Amazon Rainforest...

        with Psychotria viridis
        Psychotria viridis
        Psychotria viridis is a shrub from the coffee family, Rubiaceae. It has many local names, including Chacruna and Chacrona ....

        )
      • Epená
        Epena
        Epena is a city and seat of Epena District in the Likouala Region of northeastern Republic of the Congo....

         (Virola sp.) (contains 5-MeO-DMT
        5-MeO-DMT
        5-MeO-DMT is a powerful psychedelic tryptamine. It is found in a wide variety of plant and psychoactive toad species and, like its close relatives DMT and bufotenin , it has been used as an entheogen by South American shamans for thousands of years.-Chemistry:5-MeO-DMT was first synthesized in...

         and DMT)
      • Hawaiian baby woodrose
        Hawaiian baby woodrose
        Argyreia nervosa is a perennial climbing vine that is native to the Indian subcontinent and introduced to numerous areas worldwide, including Hawaii, Africa and the Caribbean. Though it can be invasive, it is often prized for its aesthetic value...

         (Argyreia nervosa) (contains ergot alkaloids)
      • Ololiuhqui/Coaxihuitl (Turbina/Rivea corymbosa
        Rivea corymbosa
        Turbina corymbosa Turbina corymbosa Turbina corymbosa ((syn. Rivea corymbosa), the Christmas vine, is a species of morning glory, native throughout Latin America from Mexico in the North to Peru in the South and widely naturalised elsewhere. It is a perennial climbing vine with white flowers, often...

        ) (contains ergot alkaloids)
      • Tlitliltzin/Badoh Negro
        Ipomoea violacea
        Ipomoea violacea is a perennial species of Ipomoea that occurs throughout the tropics, growing in coastal regions. It is most commonly called 'Beach Moonflower' or 'Sea Moonflower' as the flowers open at night...

         (Ipomoea violacea
        Ipomoea violacea
        Ipomoea violacea is a perennial species of Ipomoea that occurs throughout the tropics, growing in coastal regions. It is most commonly called 'Beach Moonflower' or 'Sea Moonflower' as the flowers open at night...

        ) (contains ergot alkaloids)
      • Yopo
        Yopo
        "Ebene" redirects here. For the city in Mauritius, see Ebene City.Anadenanthera peregrina, also known as Yopo, Jopo, Cohoba, Mopo, Nopo, Parica or Calcium Tree, is a perennial tree of the Anadenanthera genus native to the Caribbean and South America. It grows up to 20 m tall, having a thorny bark...

         and Cebil (Anadenanthera sp.) (contains 5-HO-DMT)
      • Iboga
        Iboga
        Tabernanthe iboga or Iboga is a perennial rainforest shrub and hallucinogen, native to western Central Africa. Iboga stimulates the central nervous system when taken in small doses and induces visions in larger doses. In parts of Africa where the plant grows the bark of the root is chewed for...

         (Tabernanthe iboga) (contains ibogaine
        Ibogaine
        Ibogaine is a naturally occurring psychoactive substance found in a number of plants, principally in a member of the Apocynaceae family known as Iboga . A hallucinogen with both psychedelic and dissociative properties, the substance is banned in some countries; in other countries it is being used...

        ) (also dissociative)
    • Cacti psychedelics
      • Peruvian Torch cactus (Trichocereus peruvianus) (contains mescaline
        Mescaline
        Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....

        )
      • Peyote
        Peyote
        Lophophora williamsii , better known by its common name Peyote , is a small, spineless cactus with psychoactive alkaloids, particularly mescaline.It is native to southwestern Texas and Mexico...

         cactus (Lophophora williamsii) (contains mescaline)
      • San Pedro cactus (Trichocereus pachanoi) (contains mescaline)
    • Quasi-psychedelics
      • Cannabis
        Cannabis
        Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...

         (contains THC
        Tetrahydrocannabinol
        Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...

        )
      • Nutmeg
        Nutmeg
        The nutmeg tree is any of several species of trees in genus Myristica. The most important commercial species is Myristica fragrans, an evergreen tree indigenous to the Banda Islands in the Moluccas of Indonesia...

         (Myristica fragrans) (contains myristicin
        Myristicin
        Myristicin is a phenylpropene, a natural organic compound present in small amounts in the essential oil of nutmeg and to a lesser extent in other spices such as parsley and dill.It is insoluble in water, but soluble in ethanol and acetone.-Uses:...

        )
    • Dissociatives
      • Iboga
        Iboga
        Tabernanthe iboga or Iboga is a perennial rainforest shrub and hallucinogen, native to western Central Africa. Iboga stimulates the central nervous system when taken in small doses and induces visions in larger doses. In parts of Africa where the plant grows the bark of the root is chewed for...

         (Tabernanthe iboga) (contains ibogaine
        Ibogaine
        Ibogaine is a naturally occurring psychoactive substance found in a number of plants, principally in a member of the Apocynaceae family known as Iboga . A hallucinogen with both psychedelic and dissociative properties, the substance is banned in some countries; in other countries it is being used...

        ) (also psychedelic
        Serotonergic psychedelic
        Serotonergic psychedelics are a class of hallucinogenic drugs with a method of action strongly tied to the serotonin neurotransmitter...

        )
      • Salvia divinorum
        Salvia divinorum
        Salvia divinorum is a psychoactive plant which can induce dissociative effects and is a potent producer of "visions" and other hallucinatory experiences...

        (contains salvinorin A
        Salvinorin A
        Salvinorin A is the main active psychotropic molecule in Salvia divinorum, a Mexican plant which has a long history of use as an entheogen by indigenous Mazatec shamans...

        ) (also considered atypically psychedelic)
    • Deliriants
      • Deadly nightshade (Atropa belladonna) (contains tropane alkaloid
        Tropane alkaloid
        Tropane alkaloids are a class of alkaloids and secondary metabolites that contain a tropane ring in their chemical structure...

        s)
      • Floripondio (Brugmansia sp.) (contains tropane alkaloids)
      • Henbane
        Henbane
        Henbane , also known as stinking nightshade or black henbane, is a plant of the family Solanaceae that originated in Eurasia, though it is now globally distributed.-Toxicity and historical usage:...

         (Hyoscyamus niger) (contains tropane alkaloids)
      • Mandrake
        Mandragora officinarum
        Mandragora officinarum is a species of the plant genus mandrake. It has a variety of medicinal uses, especially anodyne and soporific, though in the past much of the use was due to superstition.-Physical characteristics:...

         (Mandragora officinarum) (contains tropane alkaloids)
      • Jimson weed
        Datura stramonium
        Datura stramonium, known by the common names Jimson weed, devil's trumpet, devil's weed, thorn apple, tolguacha, Jamestown weed, stinkweed, locoweed, datura, pricklyburr, devil's cucumber, Hell's Bells, moonflower and, in South Africa, malpitte and mad seeds, is a common weed in the...

         (Datura stramonium) (contains tropane alkaloids)
  • Fungi
    • Psychedelics
      • Psilocybe mushrooms
        Psychedelic mushroom
        Psilocybin mushrooms are fungi that contain the psychoactive compounds psilocybin and psilocin. There are multiple colloquial terms for psilocybin mushrooms, the most common being shrooms or magic mushrooms....

         (Psilocybe sp. and some Conocybe, Panaeolus and Stropharia) (contain psilocybin
        Psilocybin
        Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...

         and psilocin
        Psilocin
        Psilocin , an aromatic compound, sometimes also spelled psilocine, psilocyn, or psilotsin, is a psychedelic mushroom alkaloid. It is found in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin...

        )
  • Animals
    • Psychedelics
      • Psychoactive toads (Bufo alvarius) (Colorado River toad
        Colorado River Toad
        The Colorado River toad, Bufo alvarius, also known as the Sonoran Desert toad, is a psychoactive toad found in northern Mexico and the southwestern United States...

        ) (contain 5-MeO-DMT
        5-MeO-DMT
        5-MeO-DMT is a powerful psychedelic tryptamine. It is found in a wide variety of plant and psychoactive toad species and, like its close relatives DMT and bufotenin , it has been used as an entheogen by South American shamans for thousands of years.-Chemistry:5-MeO-DMT was first synthesized in...

         and bufotenin
        Bufotenin
        Bufotenin , or 5-hydroxy-dimethyltryptamine , is a tryptamine related to the neurotransmitter serotonin...

        )

See also

  • Altered state of consciousness
    Altered state of consciousness
    An altered state of consciousness , also named altered state of mind, is any condition which is significantly different from a normal waking beta wave state. The expression was used as early as 1966 by Arnold M. Ludwig and brought into common usage from 1969 by Charles Tart: it describes induced...

  • Bad trip
    Bad trip
    Bad trip is a disturbing experience sometimes associated with use of a psychedelic drug such as LSD, Salvinorin A, DXM, mescaline, psilocybin, DMT and sometimes even other drugs including cannabis, alcohol and MDMA....

  • Contact high
    Contact high
    Contact high is a phenomenon that sometimes occurs in otherwise sober people and animals who come into contact with someone who is under the influence of drugs...

  • Empathogen
  • Entactogen
  • Entheogen
    Entheogen
    An entheogen , in the strict sense, is a psychoactive substance used in a religious, shamanic, or spiritual context. Historically, entheogens were mostly derived from plant sources and have been used in a variety of traditional religious contexts...

  • Ergotism
    Ergotism
    Ergotism is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the Claviceps purpurea fungus which infects rye and other cereals, and more recently by the action of a number of ergoline-based drugs. It is also known as ergotoxicosis, ergot...

  • God in a Pill?
    God in a Pill?
    God in a Pill? was a 1966 pamphlet by Meher Baba in which he spoke out strongly against taking illicit drugs like marijuana and LSD, saying they were harmful "physically, mentally, and spiritually."...

  • Hallucinogenic effects of banana peels
  • Hard and soft drugs
    Hard and soft drugs
    Hard and Soft drugs are terms to distinguish between psychoactive drugs that are addictive and perceived as especially damaging and drugs that are believed to be non-addictive and with fewer dangers associated with their use...

  • Lucid dreaming
    Lucid dreaming
    A lucid dream is a dream in which one is aware that one is dreaming. The term was coined by the Dutch psychiatrist and writer Frederik van Eeden . In a lucid dream, the dreamer can actively participate in and manipulate imaginary experiences in the dream environment. Lucid dreams can seem real and...

  • Monomyth
    Monomyth
    Joseph Campbell's term monomyth, also referred to as the hero's journey, is a basic pattern that its proponents argue is found in many narratives from around the world. This widely distributed pattern was described by Campbell in The Hero with a Thousand Faces...

  • Neurotheology
    Neurotheology
    Neurotheology, also known as spiritual neuroscience, is the study of correlations of neural phenomena with subjective experiences of spirituality and hypotheses to explain these phenomena....

  • Out-of-body experience
    Out-of-body experience
    An out-of-body experience is an experience that typically involves a sensation of floating outside of one's body and, in some cases, perceiving one's physical body from a place outside one's body ....

  • Overdose

  • Pharmacology
    Pharmacology
    Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...

  • Psilocybin mushroom
    Psilocybin mushroom
    Psilocybin mushrooms are fungi that contain the psychoactive compounds psilocybin and psilocin. There are multiple colloquial terms for psilocybin mushrooms, the most common being shrooms or magic mushrooms....

  • Psychedelic
    Psychedelic
    The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...

  • Psychedelic plants
    Psychedelic plants
    A list of plants that are used for psychedelic drugs. Some of them have been used for thousands of years for religious purposes. The plants are listed according to the substances they contain.-THC:Cannabis is a popular psychedelic plant...

  • Psychedelic psychotherapy
    Psychedelic psychotherapy
    Psychedelic therapy refers to therapeutic practices involving the use of psychedelic drugs, particularly serotonergic psychedelics such as ergine, LSD, psilocin and DMT...

  • Psychoactive or psychotropic
  • Psychonaut
  • Recreational drug use
    Recreational drug use
    Recreational drug use is the use of a drug, usually psychoactive, with the intention of creating or enhancing recreational experience. Such use is controversial, however, often being considered to be also drug abuse, and it is often illegal...

  • Research chemicals
  • Responsible drug use
    Responsible drug use
    Responsible drug use is a harm reduction strategy based on a belief that illegal recreational drug use can be responsible in terms of reduced or eliminated risk of negative impact on the lives of both the user and others....

  • Richard Evans Schultes
    Richard Evans Schultes
    Richard Evans Schultes may be considered the father of modern ethnobotany, for his studies of indigenous peoples' uses of plants, including especially entheogenic or hallucinogenic plants , for his lifelong collaborations with chemists, and...

     and Albert Hofmann
    Albert Hofmann
    Albert Hofmann was a Swiss scientist known best for being the first person to synthesize, ingest and learn of the psychedelic effects of lysergic acid diethylamide . He authored more than 100 scientific articles and a number of books, including LSD: My Problem Child...

    , Plants of the Gods
  • Sensory deprivation
    Sensory deprivation
    Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch,...

  • Set and setting
    Set and setting
    Set and setting describes the context for psychoactive and particularly psychedelic drug experiences: one's mindset and the setting in which the user has the experience. This is especially relevant for psychedelic or hallucinogenic experiences...



Further reading

The literature about psychedelics, dissociatives and deliriants is vast. The following books provide accessible and up-to-date introductions to this literature:
  • Ann & Alexander Shulgin: PIHKAL (Phenethylamines I Have Known And Loved), a Chemical Love Story
  • Ann & Alexander Shulgin: TIHKAL (Tryptamines I Have Known And Loved), the Continuation
  • Charles S. Grob, ed.: Hallucinogens, a reader
  • Winkelman, Michael J., and Thomas B. Roberts (editors) (2007).Psychedelic Medicine: New Evidence for Hallucinogens as Treatments 2 Volumes. Westport, CT: Praeger/Greenwood.

External links

  • Erowid is a web site dedicated entirely to providing information about psychoactive drugs, with an impressive collection of trip reports, materials collected from the web and usenet, and a bibliography of scientific literature
  • Evidence: Academic resources on hallucinogens- and MDMA research, relapse prevention and harm reduction.
  • The Shroomery has detailed information about magic mushrooms including identification, cultivation and spores, psychedelic images, trip reports and an active community.
  • Multidisciplinary Association for Psychedelic Studies is a nonprofit research and educational organization which carries out clinical trials and other research in order to assess the potential medicinal uses of psychedelic drugs and develop them into medicines.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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