psychedelic drug psychedelic drug psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary mental states (known as psychedelic experiences or psychedelic "trips") and/or an apparent expansion of consciousness. sometimes, they are called classic hallucinogens, serotonergic hallucinogens, or serotonergic psychedelics, and the term psychedelic is sometimes used more broadly to include various types of hallucinogens or those which are atypical or adjacent to psychedelia such as mdma or cannabis; this article uses the narrower definition of psychedelics. true psychedelics cause specific psychological, visual, and auditory changes, and oftentimes a substantially altered state of consciousness. psychedelic states are often compared to meditative, psychodynamic or transcendental types of alterations of mind. the "classical" psychedelics, the psychedelics with the largest scientific and cultural influence, are mescaline, lsd, psilocybin, and dmt. lsd in particular has long been considered the paradigmatic psychedelic compound, to which all other psychedelics are often or usually compared. synthetic mescaline. normally biosynthesized from peyote and some other cacti, mescaline was the first psychedelic compound to be extracted and isolated. most psychedelic drugs fall into one of the three families of chemical compounds: tryptamines, phenethylamines, or lysergamides (lsd is considered both a tryptamine and lysergamide). they act via serotonin 2a receptor agonism. when compounds bind to serotonin 5-ht2a receptors, they modulate the activity of key circuits in the brain involved with sensory perception and cognition, however, the exact nature of how psychedelics induce changes in perception and cognition via the 5-ht2a receptor is still unknown, although reduction in default mode network activity and increased functional connectivity between regions in the brain as a result may be one of the most relevant pharmacological mechanisms underpinning the psychedelic experience, particularly ego death. the psychedelic experience is often compared to non-ordinary forms of consciousness such as those experienced in meditation, mystical experiences, and near-death experiences, which also appear to be partially underpinned by altered default mode network activity. the phenomenon of ego death is often described as a key feature of the psychedelic experience. many psychedelic drugs are illegal worldwide under the un conventions, with occasional exceptions for religious use or research contexts. despite these controls, recreational use of psychedelics is common. legal barriers have made the scientific study of psychedelics more difficult. research has been conducted, however, and studies show that psychedelics are physiologically safe and rarely lead to addiction. studies conducted using psilocybin in a psychotherapeutic setting reveal that psychedelic drugs may assist with treating depression, alcohol addiction, and nicotine addiction. although further research is needed, existing results suggest that psychedelics could be effective treatments for certain forms of psychopathology. a 2022 survey found that 28% of americans had used a psychedelic at some point in their life. etymology and nomenclature 5-ht2a receptor the term psychedelic was coined by the psychiatrist humphrey osmond during written correspondence with author aldous huxley and presented to the new york academy of sciences by osmond in 1957. it is irregularly derived from the greek words ψυχή psychḗ 'soul, mind' and δηλείν dēleín 'to manifest', with the intended meaning "mind manifesting," the implication being that psychedelics can reveal unused potentials of the human mind. the term was loathed by american ethnobotanist richard schultes but championed by american psychologist timothy leary. aldous huxley had suggested his own coinage phanerothyme (greek phaneroein- "visible" and greek thymos "soul", thus "visible soul") to osmond in 1956. recently, the term entheogenic has come into use to denote the use of psychedelic drugs, as well as various other types of psychoactive substances, in a religious, spiritual, and mystical context. in 2004, david e. nichols wrote the following about the nomenclature used for psychedelic drugs: many different names have been proposed over the years for this drug class. the famous german toxicologist louis lewin used the name phantastica earlier in this century, and as we shall see later, such a descriptor is not so farfetched. the most popular names—hallucinogen, psychotomimetic, and psychedelic ("mind manifesting")—have often been used interchangeably. hallucinogen is now, however, the most common designation in the scientific literature, although it is an inaccurate descriptor of the actual effects of these drugs. in the lay press, the term psychedelic is still the most popular and has held sway for nearly four decades. most recently, there has been a movement in nonscientific circles to recognize the ability of these substances to provoke mystical experiences and evoke feelings of spiritual significance. thus, the term entheogen, derived from the greek word entheos, which means "god within", was introduced by ruck et al. and has seen increasing use. this term suggests that these substances reveal or allow a connection to the "divine within". although it seems unlikely that this name will ever be accepted in formal scientific circles, its use has dramatically increased in the popular media and on internet sites. indeed, in much of the counterculture that uses these substances, entheogen has replaced psychedelic as the name of choice and we may expect to see this trend continue. robin carhart-harris and guy goodwin write that the term psychedelic is preferable to hallucinogen for describing classical psychedelics because of the term hallucinogen's "arguably misleading emphasis on these compounds' hallucinogenic properties." while the term psychedelic is most commonly used to refer only to serotonergic hallucinogens, it is sometimes used for a much broader range of drugs, including empathogen–entactogens, dissociatives, and atypical hallucinogens/psychoactives such as amanita muscaria, cannabis sativa, nymphaea nouchali and salvia divinorum. thus, the term serotonergic psychedelic is sometimes used for the narrower class. it is important to check the definition of a given source. this article uses the more common, narrower definition of psychedelic. examples doses of lysergic acid diethylamide (lsd) main article: list of psychedelic drugs 2c-b (2,5-dimethoxy-4-bromophenethylamine) is a substituted phenthylamine first synthesised in 1974 by alexander shulgin. 2c-b is both a psychedelic and a mild entactogen, with its psychedelic effects increasing and its entactogenic effects decreasing with dosage. 2c-b is the most well known compound in the 2c family, their general structure being discovered as a result of modifying the structure of mescaline. dmt (n,n-dimethyltryptamine) is an indole alkaloid found in various species of plants. traditionally it is consumed by tribes in south america in the form of ayahuasca. a brew is used that consists of dmt-containing plants as well as plants containing maois, specifically harmaline, which allows dmt to be consumed orally without being rendered inactive by monoamine oxidase enzymes in the digestive system. in the western world dmt is more commonly consumed via the vaporisation of freebase dmt. whereas ayahuasca typically lasts for several hours, inhalation has an onset measured in seconds and has effects measured in minutes, being significantly more intense. particularly in vaporised form, dmt has the ability to cause users to enter a hallucinatory realm fully detached from reality, being typically characterised by hyperbolic geometry, and described as defying visual or verbal description. users have also reported encountering and communicating with entitites within this hallucinatory state. dmt is the archetypal substituted tryptamine, being the structural scaffold of psilocybin and - to a lesser extent - the lysergamides. lsd (lysergic acid diethylamide) is a derivative of lysergic acid, which is obtained from the hydrolysis of ergotamine. ergotamine is an alkaloid found in the fungus claviceps purpurea, which primarily infects rye. lsd is both the prototypical psychedelic and the prototypical lysergamide. as a lysergamide, lsd contains both a tryptamine and phenethylamine group within its structure. as a result of containing a phenethylamine group lsd agonises dopamine receptors as well as serotonin receptors, making it more energetic in effect in contrast to the more sedating effects of psilocin, which is not a dopamine agonist. mescaline (3,4,5-trimethoxyphenethylamine) is a phenethylamine alkaloid found in various species of cacti, the most well known being peyote (lophophora williamsii) and san pedro (echinopsis pachanoi). mescaline has effects comparable to those of lsd and psilocybin, albeit with a greater emphasis on colors and patterns. psilocin (4-ho-dmt) is the dephosphorylated active metabolite of the indole alkaloid psilocybin and a substituted tryptamine, which is produced in over 200 species of fungi. of the classical psychedelics psilocybin has attracted the greatest academic interest regarding its ability to manifest mystical experiences, although all psychedelics are capable of doing so to variable degrees. o-acetylpsilocin (4-aco-dmt) is an acetylated analog of psilocin. additionally, replacement of a methyl group at the dimethylated nitrogen with an isopropyl or ethyl group yields 4-ho-mipt and 4-ho-met, respectively. uses traditional preparation of ayahuasca, province of pastaza, ecuador. a number of frequently mentioned or traditional psychedelics such as ayahuasca (which contains dmt), san pedro, peyote, and peruvian torch (which all contain mescaline), psilocybe mushrooms (which contain psilocin/psilocybin) and tabernanthe iboga (which contains the unique psychedelic ibogaine) all have a long and extensive history of spiritual, shamanic and traditional usage by indigenous peoples in various world regions, particularly in latin america, but also gabon, africa in the case of iboga. different countries and/or regions have come to be associated with traditional or spiritual use of particular psychedelics, such as the ancient and entheogenic use of psilocybe mushrooms by the native mazatec people of oaxaca, mexico or the use of the ayahuasca brew in the amazon basin, particularly in peru for spiritual and physical healing as well as for religious festivals. peyote has also been used for several thousand years in the rio grande valley in north america by native tribes as an entheogen. in the andean region of south america, the san pedro cactus (echinopsis pachanoi) has a long history of use, possibly as a traditional medicine. archaeological studies have found evidence of use going back two thousand years, to moche culture, nazca culture, and chavín culture. although authorities of the roman catholic church attempted to suppress its use after the spanish conquest, this failed, as shown by the christian element in the common name "san pedro cactus" – saint peter cactus. the name is attributed to the belief that just as st peter holds the keys to heaven, the effects of the cactus allow users "to reach heaven while still on earth." in 2022, the peruvian ministry of culture declared the traditional use of san pedro cactus in northern peru as cultural heritage. although people of western culture have tended to use psychedelics for either psychotherapeutic or recreational reasons, most indigenous cultures, particularly in south america have seemingly tended to use psychedelics for more supernatural reasons such as divination. this can often be related to "healing" or health as well but typically in the context of finding out what is wrong with the individual; such as using psychedelic states to "identify" a disease and/or its cause, locate lost objects, and identify a victim or even perpetrator of sorcery. in some cultures and regions, even psychedelics themselves, such as ayahuasca and the psychedelic lichen of eastern ecuador (dictyonema huaorani) that supposedly contains both 5-meo-dmt and psilocybin, have also been used by witches and sorcerers to conduct their malicious magic, similarly to nightshade deliriants like brugmansia and latua. psychedelic therapy main article: psychedelic therapy psychedelic therapy (or psychedelic-assisted therapy) is the proposed use of psychedelic drugs to treat mental disorders. as of 2021, psychedelic drugs are controlled substances in most countries and psychedelic therapy is not legally available outside clinical trials, with some exceptions. the procedure for psychedelic therapy differs from that of therapies using conventional psychiatric medications. while conventional medications are usually taken without supervision at least once daily, in contemporary psychedelic therapy the drug is administered in a single session (or sometimes up to three sessions) in a therapeutic context. the therapeutic team prepares the patient for the experience beforehand and helps them integrate insights from the drug experience afterwards. after ingesting the drug, the patient normally wears eyeshades and listens to music to facilitate focus on the psychedelic experience, with the therapeutic team interrupting only to provide reassurance if adverse effects such as anxiety or disorientation arise. as of 2022, the body of high-quality evidence on psychedelic therapy remains relatively small and more, larger studies are needed to reliably show the effectiveness and safety of psychedelic therapy's various forms and applications. on the basis of favorable early results, ongoing research is examining proposed psychedelic therapies for conditions including major depressive disorder, and anxiety and depression linked to terminal illness. the united states food and drug administration has granted "breakthrough therapy" status, which