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Psychedelics, dissociatives and deliriants



 
 
The general group of pharmacological
Pharmacology

Pharmacology is the study of drug action. More specifically it is the study of the interactions that occur between a living organism and exogenous chemicals that alter normal biochemical function....
 agents commonly known as hallucinogens can be divided into three broad categories: psychedelic
Psychedelic drug

A psychedelic substance is any psychoactive drugs whose primary action is to alter the thought processes of the brain and perception of the mind....
s
, dissociatives, and deliriant
Deliriant

The deliriants are a special class of acetylcholine receptor-inhibitor dissociatives. The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking ....
s
. These classes of psychoactive drugs have in common that they can cause subjective changes in perception
Perception

In psychology and the cognitive sciences, perception is the process of attaining awareness or understanding of sense information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was predicted that building perceiving machines would take about a decade, a goal which is still very far from fruition....
, thought
Thought

Thought and thinking are mind Theory of forms and processes, respectively Thinking allows beings to model the world and to deal with it according to their goal, plans, ends and desires....
, emotion
Emotion

An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior.Emotions are subjective experiences, or experienced from an individual point of view....
 and consciousness
Consciousness

Consciousness is a difficult term to define, because the word is used and understood in a wide variety of ways, so that it frequently happens that what one person sees as a definition of consciousness is seen by others as about something else altogether....
. Unlike other psychoactive drug
Psychoactive drug

A psychoactive drug or psychotropic substance is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood , consciousness and behaviour....
s, such as stimulants and opioids, the hallucinogens do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness.






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Encyclopedia


The general group of pharmacological
Pharmacology

Pharmacology is the study of drug action. More specifically it is the study of the interactions that occur between a living organism and exogenous chemicals that alter normal biochemical function....
 agents commonly known as hallucinogens can be divided into three broad categories: psychedelic
Psychedelic drug

A psychedelic substance is any psychoactive drugs whose primary action is to alter the thought processes of the brain and perception of the mind....
s
, dissociatives, and deliriant
Deliriant

The deliriants are a special class of acetylcholine receptor-inhibitor dissociatives. The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking ....
s
. These classes of psychoactive drugs have in common that they can cause subjective changes in perception
Perception

In psychology and the cognitive sciences, perception is the process of attaining awareness or understanding of sense information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was predicted that building perceiving machines would take about a decade, a goal which is still very far from fruition....
, thought
Thought

Thought and thinking are mind Theory of forms and processes, respectively Thinking allows beings to model the world and to deal with it according to their goal, plans, ends and desires....
, emotion
Emotion

An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior.Emotions are subjective experiences, or experienced from an individual point of view....
 and consciousness
Consciousness

Consciousness is a difficult term to define, because the word is used and understood in a wide variety of ways, so that it frequently happens that what one person sees as a definition of consciousness is seen by others as about something else altogether....
. Unlike other psychoactive drug
Psychoactive drug

A psychoactive drug or psychotropic substance is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood , consciousness and behaviour....
s, such as stimulants and opioids, the hallucinogens 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, techniques, modalities and states of mind, awareness and consciousness. Trance states may occur involuntarily and unbidden....
, meditation
Meditation

Meditation is a mental discipline by which one attempts to get beyond the reflexive, "thinking" mind into a deeper state of relaxation or awareness....
, conversion experiences, and dreams.

One thing that most of these drugs do not do, despite the ingrained usage of the term hallucinogen, is to cause hallucination. Hallucination
Hallucination

A hallucination, in the broadest sense, 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, substantial, and located in external objective space....
s, 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 , trade name Benadryl as produced by McNeil Laboratories a division of J&J, or Dimedrol outside the U.S....
 and atropine
Atropine

Atropine is a tropane alkaloid extracted from deadly nightshade , jimsonweed , Mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a hard 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

Healing, assessed physically, is the process by which the Cell in the body regenerate and repair to reduce the size of a damaged or necrosis area.Healing incorporates both the removal of necrotic Biological tissue , and the replacement of this tissue....
 and divination
Divination

Divination is the attempt to gain insight into a question or situation by way of a standardized process or ritual. Diviners ascertain their interpretations of how a querent should proceed by reading signs, events, or omens, or through alleged contact with a supernatural agency....
, in initiation rites, and in the religious rituals of syncretistic movements such as União do Vegetal
União do Vegetal

Uni?o 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 Syncretism spiritual practice, which was founded in the Brazilian Amazonas States of Brazil of Acre State in the 1930s and became a worldwide movement in the 1990s....
, 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 peoples religion among Native Americans ....
. When used in religious practice, psychedelic drugs, as well as other substances like tobacco
Tobacco

Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines....
, are referred to as entheogens.

Albert Hofmann Oct 1993
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 a pervasive depression , low self-esteem, and anhedonia in normally enjoyable activities....
, Post-traumatic Stress Disorder
Post-traumatic stress disorder

Posttraumatic stress disorder is an anxiety disorder that can develop after exposure to one or more traumatic events that threatened or caused grave physical harm....
, Obsessive-compulsive Disorder
Obsessive-compulsive disorder

Obsessive-compulsive disorder is a mental disorder most commonly characterized by Intrusive thoughts, repetitive thoughts resulting in compulsive behaviors and mental acts that the person feels driven to perform, according to rules that must be applied rigidly, aimed at reducing anxiety by preventing some dreaded event or by resolving a more...
, alcoholism
Alcoholism

Alcoholism is a term with multiple and sometimes conflicting definitions to describe the detrimental effects of alcohol intake.In common and historic usage, alcoholism refers to any condition that results in the continued consumption of alcoholic beverages despite health problems and negative social consequences....
, opioid
Opioid

An opioid is a chemical substance that has a morphine-like action in the body. The main use is for analgesia. These agents work by binding to opioid receptors, which are found principally in the central nervous system and the gastrointestinal tract....
 addiction
Addiction

The term "addiction" is used in many contexts to describe an obsession, compulsion, or excessive physical dependence or psychological dependence, such as: drug addiction, video game addiction, crime, alcoholism, compulsive overeating, problem gambling, computer addiction, pornography addiction, etc....
, 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....
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 or questioning is interviewing as commonly employed by officers of the police and military.The interviewee is also referred to as a "source"....
, 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 where an individual reports contact with a transcendence , an encounter or union with the Divinity....
, enhanced creativity
Creativity

Creativity is a mental and social process involving the generation of new ideas or concepts, or new associations of the creative mind between existing ideas or concepts....
, personal development, and "mind expansion". The use of psychedelic drugs was a major element of the 1960s counterculture
Counterculture

Counterculture is a Sociology 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....
, where it became associated with various social movements and a general atmosphere of rebellion and strife between generations.

Despite prohibition, the recreational, spiritual, and medical use of psychedelics continues today. Organizations, such as Multidisciplinary Association for Psychedelic Studies
Multidisciplinary Association for Psychedelic Studies

The Multidisciplinary Association for Psychedelic Studies is a United States-based non-profit organization that assists scientists to design, fund, obtain approval for and report on studies into the risks and benefits of psychedelic 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. In some cases, this includes research in humans, like that conducted by Roland Griffiths and colleagues .

Psychedelics


The word psychedelic (From Ancient Greek
Ancient Greek

Ancient Greek is the historical stage in the development of the Greek language spanning across the Archaic Greece , Classical Greece , and Hellenistic civilization periods of ancient Greece and the classical antiquity....
 ???? (psychê) mind, soul + d???? (dêlos) manifest, visible + -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, LSD, LSD-25, or acid, is a semisynthetic psychedelic drug of the ergoline family. Its unusual psychological effects, which include visuals of colored patterns behind the eyes in the mind, a sense of time distorting, and crawling geometric patterns, have made it one of the most widely known psyched...
, psilocybin
Psilocybin

Psilocybin is a psychedelic drug indole of the tryptamine family, found in psilocybin mushrooms. It is present in List of Psilocybin mushrooms of fungi, including those of the genus Psilocybe, such as Psilocybe cubensis and liberty cap , but also reportedly isolated from a dozen or so other genera....
, DMT
Dimethyltryptamine

Dimethyltryptamine , also known as N,N-dimethyltryptamine, is a naturally-occurring tryptamine and potent psychedelic drug, found not only in many plants, but also in trace amounts in the human body where its natural function is undetermined....
, 2C-B
2C-B

2C-B or 4-bromo-2,5-dimethoxyphenethylamine is a Psychedelics, dissociatives and deliriants of the 2C's, an Empathogen-entactogen. It was first synthesized by Alexander Shulgin in 1974....
, mescaline
Mescaline

Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally-occurring psychedelic alkaloid of the phenethylamine class. It is mainly used as a recreational drug, an entheogen, and a tool to supplement various practices for transcendence , including in meditation, psychonautics, art projects, and psychedelic psychotherapy....
, salvinorin, and DOM
2,5-Dimethoxy-4-methylamphetamine

DOM is a psychedelic hallucinogenic drug and a substituted amphetamine of the phenethylamine class of compounds, sometimes used as an entheogen....
 as well as a panoply of other tryptamines, phenethylamines and yet more exotic chemicals, all of which appear to act mainly on the 5-HT2A receptor
5-HT2A receptor

The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor which belongs to the serotonin receptor family and is a GPCR ....
. 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 drug properties, widely known as "psychedelic mushroom", though the majority of species do not contain hallucinogenic compounds....
 mushrooms, various ayahuasca
Ayahuasca

Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis caapi vine, usually mixed with the leaves of the Psychotria bush....
 preparations, Salvia Divinorum
Salvia divinorum

Salvia divinorum, also known as Diviner?s Sage, ska Mar?a Pastora, or simply by the genus name Salvia, is a Psychoactive drug herb which can induce strong dissociative drug effects....
, peyote
Peyote

Lophophora williamsii , better known by its common name Peyote, , is a small, spineless cactus. It is native to southwestern Texas and through central Mexico....
,and San Pedro cactus.

Much debate exists not only about the nature and causes, but even about the very description of the effects of psychedelic drugs. One prominent tradition involves 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. He spent the later part of his life in the United States, living in Los Angeles from 1937 until his death in 1963....
'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 title comes from William Blake's 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. A large number of drugs, such as cannabis and MDMA
Methylenedioxymethamphetamine

MDMA , most commonly known today by the street name ecstasy , is a semisynthetic member of the amphetamine class of psychoactive drugs, a subclass of the phenethylamines.....
, produce effects that could be classified as psychedelic (especially at higher doses) but are not considered to be strictly psychedelic drugs due to other effects that may be more (or equally) prevalent, such as sedation
Sedative

A sedative is a substance that induces sedation by reducing irritability or excitement.At higher doses it may result in slurred speech, staggering gait , poor judgment, and slow, uncertain reflexes....
 or disinhibition
Disinhibition

Disinhibition is a term in psychology used to describe a lack of restraint wikt:manifest in several ways, including disregard for Convention , impulsivity, and poor risk assessment....
.

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....
. "Trips" range between the short but intense effects of intravenous DMT
Dimethyltryptamine

Dimethyltryptamine , also known as N,N-dimethyltryptamine, is a naturally-occurring tryptamine and potent psychedelic drug, found not only in many plants, but also in trace amounts in the human body where its natural function is undetermined....
 to the protracted ibogaine
Ibogaine

Ibogaine is a naturally occurring Psychoactive drug compound found in a number of plants, principally in a member of the Apocynaceae known as iboga ....
 experience, which can last for days. Appropriate dosage ranges from extremely low (LSD
LSD

Lysergic acid diethylamide, LSD, LSD-25, or acid, is a semisynthetic psychedelic drug of the ergoline family. Its unusual psychological effects, which include visuals of colored patterns behind the eyes in the mind, a sense of time distorting, and crawling geometric patterns, have made it one of the most widely known psyched...
) to rather high (mescaline
Mescaline

Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally-occurring psychedelic alkaloid of the phenethylamine class. It is mainly used as a recreational drug, an entheogen, and a tool to supplement various practices for transcendence , including in meditation, psychonautics, art projects, and psychedelic psychotherapy....
). 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 different terms used to describe a class of psychoactive drugs that produce distinctive emotional and social effects similar to those of methylenedioxymethamphetamine ....
.

Many psychedelics (LSD
LSD

Lysergic acid diethylamide, LSD, LSD-25, or acid, is a semisynthetic psychedelic drug of the ergoline family. Its unusual psychological effects, which include visuals of colored patterns behind the eyes in the mind, a sense of time distorting, and crawling geometric patterns, have made it one of the most widely known psyched...
, psilocybin
Psilocybin

Psilocybin is a psychedelic drug indole of the tryptamine family, found in psilocybin mushrooms. It is present in List of Psilocybin mushrooms of fungi, including those of the genus Psilocybe, such as Psilocybe cubensis and liberty cap , but also reportedly isolated from a dozen or so other genera....
, mescaline
Mescaline

Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally-occurring psychedelic alkaloid of the phenethylamine class. It is mainly used as a recreational drug, an entheogen, and a tool to supplement various practices for transcendence , including in meditation, psychonautics, art projects, and psychedelic psychotherapy....
, and numerous others) are non-toxic in dosages typically ingested, making it difficult to overdose on these compounds.

Dissociatives

Dissociatives are drugs that reduce (or block) signals to the conscious mind from other parts of the brain, typically (but not necessarily) by inhibiting perception of the physical senses. Such a state of sensory deprivation
Sensory deprivation

Sensory deprivation is the deliberate reduction or removal of stimulus from one or more of the senses. Simple devices such as blindfolds or Hood and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch, taste, thermoception , and 'gravity'....
 can facilitate self exploration, hallucinations, and dreamlike states of mind which may resemble some psychedelic mindstates. Essentially similar states of mind can be reached via contrasting paths—psychedelic or dissociative. That said, the entire experience, risks and benefits are markedly different.

The primary dissociatives are similar in action to PCP
Phencyclidine

Phencyclidine , also known as angel dust, is a dissociative drug formerly used as an anesthesia agent, exhibiting hallucinogenic and neurotoxic effects....
 (angel dust) and include ketamine
Ketamine

Ketamine is a drug used in human and veterinary medicine developed by Parke-Davis in 1962. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar....
 (an anaesthetic) and DXM (dextromethorphan
Dextromethorphan

Dextromethorphan is an antitussive drug. It is one of the active ingredients used to prevent coughs in many Over-the-counter drug common cold and cough medicines....
, an active ingredient in many cough syrups). Also included are nitrous oxide
Nitrous oxide

Nitrous oxide, commonly known as "laughing gas", is a chemical compound with the chemical formula Nitrogen2Oxygen. At room temperature, it is a colorless Flammability gas, with a pleasant, slightly sweet odor and taste....
, all seeds of the morning glory species and muscimol
Muscimol

Muscimol is the major psychoactive alkaloid present in many mushrooms of the Amanita genus. Unlike psilocybin, a tryptamine, muscimol is a potent, selective agonist of the GABA A receptor receptor....
 from the 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....
 (fly agaric) mushroom.

Many dissociatives also have CNS
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
 depressant
Depressant

Depressant is a chemical agent that diminishes the function or activity of a specific part of the body.The term is used in particular with regard to the central nervous system ....
 effects, thereby carrying similar risks as opioids, which can slow breathing or heart rate to levels resulting in death (when using very high doses). This does not appear to be true for all dissociatives; the principal risk of nitrous oxide seems to be due to oxygen deprivation
Hypoxia (medical)

Hypoxia is a Pathology 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. Long term use of dissociative anaesthetics such as PCP and ketamine (and possibly dextromethorphan) have been suspected to cause Olney's lesions
Olney's lesions

Olney's lesions, also known as NMDA receptor antagonist neurotoxicity , are a form of brain damage caused by high doses of dissociative anaesthetics, particularly those referred to as "uncompetitive NMDA-channel-blockers" such as ketamine, phencyclidine , and dextromethorphan ....
 (N-methyl-d-aspartate antagonist
Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a Receptor , but blocks or dampens agonist-mediated responses....
 neurotoxicity
Neurotoxicity

Neurotoxicity occurs when the exposure to natural or artificial toxic substances, which are called neurotoxins, alters the normal activity of the nervous system in such a way as to cause damage to nervous tissue....
), though these lesions have never been demonstrated in primates to date. Because of the high level of physical activity and relative imperviousness to pain induced by PCP, some deaths have been reported due to the release of myoglobin from ruptured muscle cells. High amounts of myoglobin can induce renal shutdown

Deliriants

The deliriants (or anticholinergic
Anticholinergic

An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central nervous system and the peripheral nervous system....
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 the neurotransmitter acetylcholine....
s (unlike muscarine
Muscarine

Muscarine, L--muscarine, or muscarin is a Secondary metabolite found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly Clitocybe dealbata....
 and nicotine
Nicotine

Nicotine is an alkaloid found in the nightshade family of plants which constitutes approximately 0.6?3.0% of dry weight of tobacco, with biosynthesis taking place in the roots, and accumulating in the leaves....
 which are agonist
Agonist

An agonist is a term used to describe a type of Ligand or drug that binds and alters the activity of a Receptor . The ability to alter the activity of a receptor, also known as the agonist's efficacy is a property that distinguishes it from receptor antagonist, a type of receptor ligand which also binds a receptor but which does not alter t...
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

A dissociative is a drug which reduces signals to the conscious mind from other parts of the brain, typically, but not necessarily, limited to the senses....
 can produce effects similar to lucid dreaming
Lucid dreaming

A lucid dream is a dream in which the person is aware that they are dreaming while the dream is in progress, also known as a conscious dream....
 (during which one is consciously aware of dreaming while doing such), the deliriants have effects akin to sleepwalking
Sleepwalking

Sleepwalking is a parasomnia or sleep disorder where the sufferer engages in activities that are normally associated with wakefulness while he or she is sleep or in a sleep-like state....
 (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 belonging to the nightshades family . Because mandrake contains deliriant hallucinogenic tropane alkaloids such as hyoscyamine and the roots sometimes contain bifurcations causing them to resemble human figures, their roots have long been used in magic rituals, t...
, henbane
Henbane

Henbane , also known as stinking nightshade, is a plant of the family Solanaceae that originated in Eurasia, though it is now globally distributed....
 and datura
Datura

Datura is a genus of nine species of Vespertine flowering plants belonging to the family Solanaceae. Their exact natural distribution is uncertain, due to extensive cultivation and naturalisation throughout the temperate and tropical regions of the globe, but is most likely restricted to the Americas, from the United States south throug...
, as well as a number of pharmaceutical drugs, when taken in very high doses, such as the first-generation antihistamines diphenhydramine
Diphenhydramine

Diphenhydramine hydrochloride , trade name Benadryl as produced by McNeil Laboratories a division of J&J, or Dimedrol outside the U.S....
 (Benadryl), its close relative dimenhydrinate
Dimenhydrinate

Dimenhydrinate is an over-the-counter drug used to prevent nausea and motion sickness. It is marketed in Portugal as Viabom, but in prescription format....
 (Dramamine or Gravol) and hydroxyzine
Hydroxyzine

Hydroxyzine is a first-generation antihistamine, of the piperazine class that is an histamine receptor antagonist. It was synthesised in the early 1950s and the medicinal formulation of this drug was announced in the 04 August 1956 issue of Chemistry Week....
, to name a few. Native Americans also consumed massive amounts of tobacco
Tobacco

Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is 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 typically include dehydration
Dehydration

Dehydration is the removal of water from an object. In Physiology terms, it entails a relative deficiency of water molecules in relation to other dissolved solutes....
 and mydriasis
Mydriasis

Mydriasis is an excessive dilation of the pupil due to disease, Physical trauma, or the use of drugs. Normally, the pupil dilates in the dark and constriction in the light to improve vividity at night and to protect the retina from sunlight damage during the day....
 (dilation of the pupils).


Most modern-day psychonaut
Psychonaut

A psychonaut is a person who experiences intentionally induced altered states of consciousness in an attempt to investigate his or her mind, and possibly address spiritual questions, through direct experience....
s 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 humankind, 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 have a stem , a cap , and gills on the unde...
s, cacti
Cactus

A cactus is any member of the spine plant family Cactaceae, native to the Americas. They are often used as ornamental plants, but some are also Crop plants....
 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

Societies define Crime as the breach of one or more rules or laws for which some Government or force may ultimately prescribe a punishment.The word crime originates from the Latin crimen , from the Latin root cerno and Greek ????? = "I judge"....
 punishable by fines, imprisonment or even death
Capital punishment

Capital punishment, the death penalty or execution, is the killing of a person by procedural law for Punishment#Retribution and Punishment#Incapacitation....
. In some countries, such as the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 and the Netherlands
Netherlands

The Netherlands is a country that is part of the Kingdom of the Netherlands. It is a parliamentary democratic constitutional monarchy. The Netherlands is located in North-West Europe, and bordered by the North Sea to the north and west, Belgium to the south, and Germany to the east....
, partial deference may be granted to traditional religious use by members of indigenous
Indigenous

Indigenous may refer to:*Indigenous peoples, population groups with ancestral connections to place prior to formally recorded history**Indigenous intellectual property, a legal term identifying the right to claim knowledge within their culture...
 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 peoples religion among Native Americans ....
 and the Santo Daime
Santo Daime

Santo Daime is a Syncretism spiritual practice, which was founded in the Brazilian Amazonas States of Brazil of Acre State in the 1930s and became a worldwide movement in the 1990s....
 Church. Recently the União do Vegetal
União do Vegetal

Uni?o 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, a Monotheism#Christian view religion centered on the life and teachings of Jesus and interpreted by Christians to have been prophesied in the Hebrew Bible/Old 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 caapi vine, usually mixed with the leaves of the Psychotria bush....
.

Traditional religious and shamanic use

Historically, hallucinogens have not been most commonly used in religious or shamanic
Shamanism

Shamanism is a range of traditional beliefs and practices concerned with communication with the spirit world. A practitioner of shamanism is known as a shaman, , noun ....
 ritual
Ritual

A ritual is a set of repeated actions, often thought to have symbolic value, the performance of which is usually prescribed by a religion or by the traditions of a community by religious or political laws because of the perceived efficacy of those actions....
s. In this context they are often 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 a term often used to describe the period before Recorded history. Paul Tournal originally coined the term Pr?-historique in describing the finds he had made in the caves of southern France....
 times, as well as in numerous ancient cultures, including the Ancient Egypt
Ancient Egypt

Ancient Egypt was an Ancient history civilization in eastern North Africa, concentrated along the lower reaches of the Nile in what is now the modern nation of Egypt....
ian, Mycenaean, Ancient Greek, Vedic, Maya, Inca
Inca

The Inca civilization began as a tribe in the Cuzco area, where the legendary first Sapa Inca, Manco Capac founded the Kingdom of Cuzco around 1200....
 the and Aztec
Aztec

Aztec is a term used to refer to certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl and who achieved political and military dominance over large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the Late post-Classic period in Mesoamerican chronology....
 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....
 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 caapi vine, usually mixed with the leaves of the Psychotria bush....
 shamanism
Shamanism

Shamanism is a range of traditional beliefs and practices concerned with communication with the spirit world. A practitioner of shamanism is known as a shaman, , noun ....
, coupled with an animistic belief system.
Urarina Shaman B Dean
The rise of the Abrahamic religions (Judaism
Judaism

Judaism is a set of beliefs and practices originating in the Hebrew Bible , as later further explored and explained in the Talmud and other texts....
, Christianity
Christianity

Christianity is a Monotheistic religion #Christian view religion centered on the life and teachings of Jesus as New Testament view on Jesus' life....
 and Islam
Islam

Islam is a Monotheism, Abrahamic religion originating with the teachings of the Prophets of Islam Muhammad, a 7th century Arab religious and political figure....
) caused a decline of entheogen
Entheogen

An entheogen , in the strictest sense, is a psychoactive substance used in a religion or shamanism context. Historically, entheogens are derived primarily 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 ceremony 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 entheogenic rites in Western Europe were accused of associating with the devil
Devil

The Devil is the title given to the supernatural being, who, in mainstream Christianity, Islam, and some other religions, is believed to be a powerful, evil entity and the tempter of humankind....
. 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 term Western world, the West or the Occident can have multiple meanings dependent on its context . Accordingly, the basic definition of what constitutes "the West" varies, expanding and contracting over time, in relation to various historical circumstances....
 science
Science

In its broadest sense, science refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research....
. Earlier beginnings include scientific studies of nitrous oxide
Nitrous oxide

Nitrous oxide, commonly known as "laughing gas", is a chemical compound with the chemical formula Nitrogen2Oxygen. At room temperature, it is a colorless Flammability gas, with a pleasant, slightly sweet odor and taste....
 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 Germany pharmacologist. In 1886, he published the first methodical analysis of the Peyote cactus.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 federalism constitutionalism 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 Mexico....
 magic mushrooms
Psychedelic mushroom

Psilocybin mushrooms are fungus mainly of the psilocybe genus that contain the Psychedelic drug substances psilocybin and psilocin, and occasionally other psychoactive tryptamines....
 (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 Entheogen or Psychedelics, dissociatives and deliriants plants , for his lifelong collaborations with chemists, and for his charismatic influence as an educator at Harvard University on a num...
). Arguably the most important pre-World War II
World War II

World War II, or the Second World War , was a global military conflict which involved a Participants in World War II, including all of the great powers, organised into two opposing military alliances: the Allies of World War II and the Axis powers....
 development was by Albert Hofmann
Albert Hofmann

Albert Hofmann was a Switzerland scientist best known for having been the first to Chemical synthesis, ingestion and learn of the psychedelic effects of lysergic acid diethylamide ....
's 1938 discovery of the semi-synthetic
Chemical synthesis

In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product , or several products. This happens by physics 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 a Medicine Specialty devoted to the Treatment of mental disorders, Biomedical research and Prevention of mental disorder. The term was first coined by the German physician Johann Christian Reil in 1808....
, owing mainly to the invention of LSD. Interest in the drugs tended to focus on either the potential for psychotherapeutic
Psychotherapy

Psychotherapy is an intentional interpersonal relationship used by trained psychotherapists to aid a wiktionary:Client in problems of living. It aims to increase the individual's sense of health and reduce their subjective sense of discomfort....
 applications of the drugs (see psychedelic psychotherapy
Psychedelic psychotherapy

Psychedelic therapy refers to therapy practices involving the use of psychedelic drugs, particularly serotonergic psychedelics such as Lysergic acid diethylamide, psilocin and Dimethyltryptamine....
), or on the use of hallucinogens to produce a "controlled psychosis
Psychosis

Psychosis , with adjective psychotic, literally means abnormal condition of the mind, and is a generic psychiatry 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 , from the Ancient Greek Root schizein and phren, phren- is a psychiatry diagnosis that describes a mental disorder characterized by abnormalities in the perception or expression of reality....
. 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 poison of chemical substances as weapons to kill, injure, or incapacitate an Enemy .This type of warfare is distinct from the use of conventional weapons or nuclear weapons because the destructive effects of chemical weapons are not primarily due to their explosion force....
. Most famously, several incidents associated with the CIA
Central Intelligence Agency

The Central Intelligence Agency is a civilian intelligence agency of the Federal government of the United States. It is the successor of the Office of Strategic Services formed during World War II to coordinate espionage activities between the branches of the US military services....
's MK-ULTRA mind control
Mind control

Mind control is a broad range of psychology tactics able to subvert an individual's control of his own thought, behavior, emotions, or decisions....
 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 term Western world, the West or the Occident can have multiple meanings dependent on its context . Accordingly, the basic definition of what constitutes "the West" varies, expanding and contracting over time, in relation to various historical circumstances....
. 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. He spent the later part of his life in the United States, living in Los Angeles from 1937 until his death in 1963....
'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 title comes from William Blake's 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. It is mainly used as a recreational drug, an entheogen, and a tool to supplement various practices for transcendence , including in meditation, psychonautics, art projects, and psychedelic psychotherapy....
, 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 Sociology 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....
 icons such as Jerry Garcia
Jerry Garcia

Jerome John "Jerry" Garcia was an American musician best known for his work with the band the Grateful Dead. Though he vehemently disavowed the role, Garcia was viewed by many as the leader or "spokesman" of the group....
, Timothy Leary
Timothy Leary

Timothy Francis Leary was an American writer, psychologist, futurist, and advocate of psychedelic drug research and one of the first people whose remains have been sent into space....
, Allen Ginsberg
Allen Ginsberg

Irwin Allen Ginsberg was an United States poet. Ginsberg is best known for the poem "Howl" , celebrating his friends who were members of the Beat Generation and attacking what he saw as the destructive forces of materialism and conformity in the United States....
 and Ken Kesey
Ken Kesey

Kenneth Elton Kesey was an United States author, best known for his novel One Flew Over the Cuckoo's Nest , and as a counter-cultural figure who, some consider , was a link between the Beat Generation of the 1950s and the hippies of the 1960s....
 advocated the drugs for their psychedelic
Psychedelic

The word 'psychedelic' is an English term coined from the Greek language words for "soul," ???? , and "manifest," d???? . A psychedelic experience is characterized by the perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly ordinary fetters....
 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....
 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 began in the United States during the early 1960s and spread around the world. The word hippie derives from hipster , and was initially used to describe beatniks who had moved into San Francisco's Haight-Ashbury district....
s with whom it was heavily associated, LSD was banned in the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 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.

Psychedelics and mental illnesses in long-term users

Most psychedelics are not known to have long-term physical toxicity. However, amphetamine-like psychedelics, 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 or neurotransmitter vesicles store various neurotransmitters that are exocytosis at the chemical synapse. The release is regulated by a calcium channel....
. 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 that often impairs the sufferer's motor skills and speech, as well as other functions....
, senility, schizophrenia
Schizophrenia

Schizophrenia , from the Ancient Greek Root schizein and phren, phren- is a psychiatry diagnosis that describes a mental disorder characterized by abnormalities in the perception or expression of reality....
, 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, LSD, LSD-25, or acid, is a semisynthetic psychedelic drug of the ergoline family. Its unusual psychological effects, which include visuals of colored patterns behind the eyes in the mind, a sense of time distorting, and crawling geometric patterns, have made it one of the most widely known psyched...
, nor to dissociatives or deliriants.

No clear connection has been made between psychedelic drugs and organic brain damage; however, high doses over time of some dissociatives and deliriant
Deliriant

The deliriants are a special class of acetylcholine receptor-inhibitor dissociatives. The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking ....
s have been shown to cause Olney's lesions
Olney's lesions

Olney's lesions, also known as NMDA receptor antagonist neurotoxicity , are a form of brain damage caused by high doses of dissociative anaesthetics, particularly those referred to as "uncompetitive NMDA-channel-blockers" such as ketamine, phencyclidine , and dextromethorphan ....
 in other animals, and have been suspected to occur in humans. Additionally, hallucinogen persisting perception disorder
Hallucinogen persisting perception disorder

Hallucinogen Persisting Perception Disorder or HPPD is a disorder characterized by a continual presence of Visual perception disturbances that are reminiscent of those generated by the ingestion of hallucinogenic substances....
 (HPPD) is a diagnosed condition wherein visual effects of drugs persist for a long time, although science and medicine have yet to determine what causes the condition.

Naming and taxonomy


Introduction to the psychedelic name zoo

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 Germany pharmacologist. In 1886, he published the first methodical analysis of the Peyote cactus.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 word 'psychedelic' is an English term coined from the Greek language words for "soul," ???? , and "manifest," d???? . A psychedelic experience is characterized by the perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly ordinary fetters....
, psychotomimetic
Psychotomimetic

A drug with psychotomimetic actions mimics the symptoms of psychosis, including delusions and/or 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 , with adjective psychotic, literally means abnormal condition of the mind, and is a generic psychiatry 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, which has since been discredited . It remained for a long time somewhat of a shibboleth to be used in the titles of papers as a signal that the researcher disapproved of the casual use of a drug, but has now been displaced in the medical literature by hallucinogen. The latter term is not entirely accurate, since hallucinations, strictly speaking, must be entirely realistic but have no basis in reality, while psychedelic effects are often better described as distortions of the ordinary senses.

While the word psychotomimetic is now outmoded, the theory it implies is still clearly visible in the World Health Organization
World Health Organization

The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health....
's definition of a hallucinogen as "a chemical agent that induces alterations in perception, thinking, and feeling which resemble those of the functional psychoses without producing the gross impairment of memory and orientation characteristic of the organic syndromes".

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 word 'psychedelic' is an English term coined from the Greek language words for "soul," ???? , and "manifest," d???? . A psychedelic experience is characterized by the perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly ordinary fetters....
s, dissociatives, and deliriant
Deliriant

The deliriants are a special class of acetylcholine receptor-inhibitor dissociatives. The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking ....
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 and atomic number 7 and atomic mass 14.00674?. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere....
 and are therefore classified as alkaloids. THC
Tetrahydrocannabinol

Tetrahydrocannabinol , also known as THC, ?9-THC, ?9-tetrahydrocannabinol, ?1-tetrahydrocannabinol , or dronabinol, is the main psychoactive substance found in the Cannabis plant....
 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 is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract 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 any psychoactive drugs whose primary action is to alter the thought processes of the brain and perception of the mind....
, 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 any psychoactive drugs whose primary action is to alter the thought processes of the brain and perception of the mind....
     (5-HT2A receptor
    5-HT2A receptor

    The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor which belongs to the serotonin receptor family and is a GPCR ....
     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
      • Lysergamides
        Ergoline

        Ergoline is a chemical Chemical compound whose structural skeleton is contained in a diverse range of alkaloids and a few psychedelic Psychoactive drug ....
    • Phenethylamine
      Phenethylamine

      Phenethylamine, or ?-phenylethylamine or 2-phenylethylamine, is an alkaloid and monoamine. Phenethylamine also has a constitutional isomer a-phenylethylamine , which has two stereoisomers: --1-phenylethylamine and --1-phenylethylamine....
      s
      • Amphetamine
        Amphetamine

        Amphetamine and related drugs such as methamphetamine are a group of drugs that act by increasing levels of norepinephrine, serotonin, and dopamine in the brain....
        s
    • Piperazines
  • Cannabinoids
    Cannabinoids

    Cannabinoids are a group of terpenephenolic compounds present in Cannabis . The broader definition of cannabinoids refers to a group of substances that are structurally related to tetrahydrocannabinol or that bind to cannabinoid receptors....
     (CB-1 receptor agonists)
  • Dissociatives
    Dissociative drug

    A dissociative is a drug which reduces signals to the conscious mind from other parts of the brain, typically, but not necessarily, limited to the senses....
    • NMDA
      NMDA

      NMDA is an amino acid derivative acting as a specific agonist at the NMDA receptor, and therefore mimics the action of the neurotransmitter glutamate on that receptor....
       receptor antagonists
    • ?-Opioid receptor agonists
    • Inhalant
      Inhalant

      Inhalants are a broad range of drugs in the forms of gases,aerosols, or solvents which are breathed in and absorbed through the lungs. While some inhalant drugs are used for List of medical inhalants, as in the case of nitrous oxide , this article focuses on the non-medical use of inhalants, as recreational drugs which are used for their int...
      s
  • Deliriant
    Deliriant

    The deliriants are a special class of acetylcholine receptor-inhibitor dissociatives. The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking ....
    s (anticholinergic
    Anticholinergic

    An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central nervous system and the peripheral nervous system....
    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

is a stimulant and sympathomimetics psychoactive drug. It is a member of the family of phenylethylamines. The levorotary levomethamphetamine is an over-the-counter drug and used in Vicks Inhalers for nasal decongestion and does not possess the Central nervous system activity of dextro or racemic methamphetamine....
 and ecstasy are substituted amphetamines, but methamphetamine has a lot stronger stimulant action than ecstasy, with none of the latter's empathogenic effects. LSD can be seen as both a tryptamine and phenethylamine. Also, drugs commonly act on more than one receptor; DXM
Dextromethorphan

Dextromethorphan is an antitussive drug. It is one of the active ingredients used to prevent coughs in many Over-the-counter drug common cold and cough medicines....
, 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.

Even so, in many cases structure-based frameworks are still very useful, and the identification of a biologically active pharmacophore
Pharmacophore

A pharmacophore was first defined by Paul Ehrlich in 1909 as "a molecular scaffold that carries the essential features responsible for a drug?s biological activity" ....
 and synthesis of analogues of known active substances remains an integral part of modern medicinal chemistry
Medicinal chemistry

Medicinal or pharmaceutical chemistry is a discipline at the intersection of chemistry and pharmacology involved with drug design, organic synthesis and developing pharmaceutical medication....
.

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 caapi vine, usually mixed with the leaves of the Psychotria bush....
         (contains DMT
        Dimethyltryptamine

        Dimethyltryptamine , also known as N,N-dimethyltryptamine, is a naturally-occurring tryptamine and potent psychedelic drug, found not only in many plants, but also in trace amounts in the human body where its natural function is undetermined....
         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....
         with Psychotria viridis
        Psychotria viridis

        Psychotria viridis is a shrub from the coffee family, Rubiaceae. It has many local names, including Chacruna and Chacrona .It is a close relative of the Ecuadorian Psychotria carthagensis, known as samiruka , and some dispute remains as to whether or not the two are actually separate species....
        )
      • Epená
        Epena

        Epena is a city and seat of Epena District in the Likouala Region of northeastern Republic of the Congo.References...
         (Virola sp.) (contains 5-MeO-DMT
        5-MeO-DMT

        5-MeO-DMT is a powerful psychedelic drug tryptamine. It is found in a wide variety of plant and psychoactive toad species, and like its close relatives Dimethyltryptamine and bufotenin , it has been used as an entheogen by South American shamanism for thousands of years....
         and DMT)
      • Hawaiian baby woodrose
        Hawaiian baby woodrose

        Hawaiian Baby Woodrose , not to be confused with the Hawaiian woodrose , is a perennial plant climbing vine, also known as Elephant Creeper and Woolly Morning Glory....
         (Argyreia nervosa) (contains ergot alkaloids)
      • Ololiuhqui/Coaxihuitl (Turbina/Rivea corymbosa
        Rivea corymbosa

        Rivea corymbosa , is a species of morning glory, native throughout Latin America from Mexico in the North to Peru in the South and widely naturalised elsewhere....
        ) (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 blooms, white in colour, 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 blooms, white in colour, open at night....
        ) (contains ergot alkaloids)
    • 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. It is mainly used as a recreational drug, an entheogen, and a tool to supplement various practices for transcendence , including in meditation, psychonautics, art projects, and psychedelic psychotherapy....
        )
      • Peyote
        Peyote

        Lophophora williamsii , better known by its common name Peyote, , is a small, spineless cactus. It is native to southwestern Texas and through central 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 L., Cannabis indica Lam., and Cannabis ruderalis Janisch....
         (contains THC
        Tetrahydrocannabinol

        Tetrahydrocannabinol , also known as THC, ?9-THC, ?9-tetrahydrocannabinol, ?1-tetrahydrocannabinol , or dronabinol, is the main psychoactive substance found in the Cannabis plant....
        )
      • Nutmeg
        Nutmeg

        The nutmegs Myristica are a genus of evergreen trees indigenous to tropical southeast Asia and Australasia. They are important for two spices derived from the fruit, nutmeg and mace....
         (Myristica fragrans) (contains myristicin
        Myristicin

        Myristicin, 3-methoxy,4,5-methylendioxy-allylbenzene, is a natural organic compound present in the essential oil of nutmeg and to a lesser extent in other spices such as parsley and dill....
        )
    • Dissociatives
      • Iboga
        Iboga

        Tabernanthe iboga or Iboga is a Perennial plant rainforest shrub and Psychedelics, dissociatives and deliriants, native to western Central Africa....
         (Tabernanthe iboga) (contains ibogaine
        Ibogaine

        Ibogaine is a naturally occurring Psychoactive drug compound found in a number of plants, principally in a member of the Apocynaceae known as iboga ....
        )
      • Salvia divinorum
        Salvia divinorum

        Salvia divinorum, also known as Diviner?s Sage, ska Mar?a Pastora, or simply by the genus name Salvia, is a Psychoactive drug herb which can induce strong dissociative drug effects....
         (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....
        )
    • Deliriants
      • Deadly nightshade
        Deadly nightshade

        Atropa belladonna or Atropa bella-donna, commonly known as belladonna or deadly nightshade, is a perennial plant herbaceous plant in the family Solanaceae, native to Europe, North Africa, and Western Asia....
         (Atropa belladonna) (contains tropane alkaloid
        Tropane alkaloid

        Tropane alkaloids, also known as Belladonna 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, is a plant of the family Solanaceae that originated in Eurasia, though it is now globally distributed....
         (Hyoscyamus niger) (contains tropane alkaloids)
      • Mandrake
        Mandrake (plant)

        Mandrake is the common name for members of the plant genus Mandragora belonging to the nightshades family . Because mandrake contains deliriant hallucinogenic tropane alkaloids such as hyoscyamine and the roots sometimes contain bifurcations causing them to resemble human figures, their roots have long been used in magic rituals, t...
         (Mandragora sp.) (contains tropane alkaloids)
      • Thorn Apple/Jimson Weed
        Datura stramonium

        Datura stramonium, known by the common names jimson weed, ditch weed, stink weed, loco weed, Korean morning glory, Jamestown weed, thorn apple, angel's trumpet, devil's trumpet, devil's snare, devil's seed, mad hatter, crazy tea, malpitte, and, along with...
         (Datura sp.) (contains tropane alkaloids)
  • Fungi
    • Psychedelics
      • Psilocybe mushrooms
        Psychedelic mushroom

        Psilocybin mushrooms are fungus mainly of the psilocybe genus that contain the Psychedelic drug substances psilocybin and psilocin, and occasionally other psychoactive tryptamines....
         (Psilocybe sp. and some Conocybe, Panaeolus and Stropharia) (contain psilocybin
        Psilocybin

        Psilocybin is a psychedelic drug indole of the tryptamine family, found in psilocybin mushrooms. It is present in List of Psilocybin mushrooms of fungi, including those of the genus Psilocybe, such as Psilocybe cubensis and liberty cap , but also reportedly isolated from a dozen or so other genera....
         and psilocin
        Psilocin

        Psilocin sometimes also spelled psilocine, psilocyn, or psilotsin, is a psychedelic drug mushroom alkaloid. It is found in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin....
        )
      • Ergot
        Ergot

        Ergot refers to a group of fungus of the genus Claviceps . The most prominent member of this group is Claviceps purpurea. This fungus grows on rye and related plants, and can cause ergotism in humans and other mammals consuming seeds contaminated with the fruiting structure of this fungus, called an ergot sclerotium....
         fungus (Claviceps purpurea) (not hallucinogenic in itself, but contains ergotamine
        Ergotamine

        Ergotamine is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It possesses structural similarity to several neurotransmitters, and has biological activity as a vasoconstrictor....
        , along with deadly poisons)
    • Dissociatives
      • Fly Agaric mushroom (Amanita muscaria) (contains muscimol
        Muscimol

        Muscimol is the major psychoactive alkaloid present in many mushrooms of the Amanita genus. Unlike psilocybin, a tryptamine, muscimol is a potent, selective agonist of the GABA A receptor receptor....
        )
  • Animals
    • Psychedelics
      • Psychoactive toads (Bufo alvarius) (contain 5-MeO-DMT and bufotenine)


See also

  • Contact high
    Contact high

    Contact high is a phenomenon that sometimes occurs in human and animals who come into contact with someone who is under the influence of recreational drug....
  • Empathogen
  • Entactogen
  • Entheogen
    Entheogen

    An entheogen , in the strictest sense, is a psychoactive substance used in a religion or shamanism context. Historically, entheogens are derived primarily 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....
  • Hallucinogenic effects of banana peels
  • Psilocybin mushroom
  • Psychedelic
    Psychedelic

    The word 'psychedelic' is an English term coined from the Greek language words for "soul," ???? , and "manifest," d???? . A psychedelic experience is characterized by the perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly ordinary fetters....
  • Psychoactive or psychotropic
  • Pharmacology
    Pharmacology

    Pharmacology is the study of drug action. More specifically it is the study of the interactions that occur between a living organism and exogenous chemicals that alter normal biochemical function....
  • Psychedelic psychotherapy
    Psychedelic psychotherapy

    Psychedelic therapy refers to therapy practices involving the use of psychedelic drugs, particularly serotonergic psychedelics such as Lysergic acid diethylamide, psilocin and Dimethyltryptamine....
  • Research chemicals
  • 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 Entheogen or Psychedelics, dissociatives and deliriants plants , for his lifelong collaborations with chemists, and for his charismatic influence as an educator at Harvard University on a num...
     and Albert Hofmann
    Albert Hofmann

    Albert Hofmann was a Switzerland scientist best known for having been the first to Chemical synthesis, ingestion and learn of the psychedelic effects of lysergic acid diethylamide ....
    , Plants of the Gods
  • 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....
  • Psychedelic plants
    Psychedelic plants

    Psychedelic plants are plants that contain psychedelic drugs. Some of them have been used for thousands of years for religious purposes....
  • Psychonaut
    Psychonaut

    A psychonaut is a person who experiences intentionally induced altered states of consciousness in an attempt to investigate his or her mind, and possibly address spiritual questions, through direct experience....
  • Recreational drug use
    Recreational drug use

    Recreational drug use is the use of psychoactive drugs for recreational purposes rather than for employment, Medicine or Spirituality purposes, although the distinction is not always clear ....
  • Responsible drug use
    Responsible drug use

    Responsible drug use is a harm reduction strategy which argues that people can Law use controlled drugs or other drugs , with reduced or eliminated risk of negatively affecting other parts of their lives or those of others....
  • Hard and soft drugs
    Hard and soft drugs

    The terms hard and soft drugs reflect distinctions made between various psychoactive drug, generally in connection with their use without prescription....
  • 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....
  • Lucid dreaming
    Lucid dreaming

    A lucid dream is a dream in which the person is aware that they are dreaming while the dream is in progress, also known as a conscious dream....
  • Sensory deprivation
    Sensory deprivation

    Sensory deprivation is the deliberate reduction or removal of stimulus from one or more of the senses. Simple devices such as blindfolds or Hood and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch, taste, thermoception , and 'gravity'....
  • 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 human body from a place outside one's body ....
  • Overdose
  • Bad trip
    Bad trip

    Bad trip is a slang term for a psychedelic crisis, a disturbing experience sometimes associated with use of a Psychedelics, dissociatives and deliriants such as LSD, Salvia divinorum, mescaline, or psilocybin....
  • Monomyth
    Monomyth

    The term Monomyth as used within the field of comparative mythology refers to a basic pattern supposedly found in many narratives from around the world....
  • Neurotheology
    Neurotheology

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


Footnotes


Literature

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

  • 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
  • : Academic resources on hallucinogens- and MDMA research, relapse prevention and harm reduction.
  • has detailed information about magic mushrooms including identification, cultivation and spores, psychedelic images, trip reports and an active community.