hallucinogen
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What are hallucinogens?
Hallucinogens are psychoactive substances that cause changes in perception, thinking, and emotions and can induce dreamlike states of consciousness. These drugs can produce distortions of the senses (illusions) or cause people to see objects that are not there (hallucinations).
Common hallucinogens include LSD, mescaline, and psilocybin. Tetrahydrocannabinol (THC), the active ingredient in marijuana, is sometimes considered a hallucinogen as well.
Hallucinogens have a long history of use in religious and spiritual rituals. Some researchers are exploring their potential therapeutic applications for psychiatric problems such as addiction, anxiety, and depression.
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How do hallucinogens affect the brain?
Hallucinogens, or psychedelics, are substances that can cause changes in perception, thought, and feelings, sometimes mimicking the symptoms of psychosis. These drugs can disrupt nerve transmission by either decreasing or increasing it, which leads to a distortion of sensory input and "jamming" of brain circuits.
Examples of hallucinogens include LSD, mescaline, psilocybin, and THC. These substances can induce a physiological response similar to that of a central nervous system stimulant, such as elevated blood pressure and excitation of the sympathetic nervous system. Use of hallucinogens may lead to altered states of consciousness, such as distortions of time and space, intense emotions, and dream-like experiences.
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What are some common types of hallucinogens?
Hallucinogens are substances that cause changes in perception, thought, and feelings, sometimes creating hallucinations.
Common hallucinogens include:
* LSD (d-lysergic acid diethylamide) A synthetic drug derived from ergot alkaloids, known for its potent effects on perception and mood.
* Mescaline The active component of the peyote cactus, used historically by native societies for its hallucinogenic properties.
* Psilocybin and Psilocin These come from certain Mexican mushrooms. They produce mind-altering effects by interacting with serotonin receptors in the brain.
* Other hallucinogens Bufotenine, harmine, methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), phencyclidine (PCP), and tetrahydrocannabinol (THC).6 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What changes do hallucinogens cause in perception or mood?
Hallucinogens can cause changes in perception, thought, and feeling, ranging from illusions to hallucinations. They can also induce a physiological response that is consistent with the type of effect expected of a central-nervous-system stimulant.
These drugs can cause swings in mood, perceptual distortions, delusions, and feelings of strangeness. Hallucinogens may heighten sensory signals, but this is often accompanied by a loss of control over what is experienced. Users may experience vivid colors or auras around objects and people, witness objects morphing into other forms, and perceive sounds as more complex and profound. They may even experience synesthesia, a scrambling of the senses in which a person may see sounds, hear colors, and taste forms.
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How are hallucinogens different from other types of drugs?
Hallucinogens are distinct from other drugs due to their capacity to induce significant changes in perception, thinking, and emotions. These drugs can cause distortions of the senses, such as illusions or hallucinations.
Unlike other psychotropic drugs that primarily affect mood, anxiety, or psychotic symptoms, hallucinogens create distortions in perception without causing loss of consciousness. They disrupt the orderly input of information in the nervous system, leading to altered states of awareness and expanded consciousness. Examples of hallucinogens include LSD, mescaline, and psilocybin.
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What risks or side effects can occur when using hallucinogens?
Hallucinogens can cause varied psychological effects, including changes in perception, thought, and feeling. These drugs can induce distortions, illusions, and hallucinations.
Adverse effects include mood swings, perceptual distortions, and impulsive behavior, which can be particularly dangerous if the individual is alone. Though rare, acts of aggression and psychotic reactions requiring psychiatric hospitalization can occur. There is no physical dependence or withdrawal symptoms associated with long-term use. However, individuals may become psychologically dependent.
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hallucinogen, substance that produces psychological effects that tend to be associated with phenomena such as dreams or religious exaltation or with mental disorders such as schizophrenia. Hallucinogens produce changes in perception, thought, and feeling, ranging from distortions of what is sensed (illusions) to sensing objects where none exist (hallucinations). Hallucinogens heighten sensory signals, but this is often accompanied by loss of control over what is experienced.
Psychopharmacological drugs
The psychopharmacological drugs that have aroused widespread interest and controversy are those that produce marked aberrations in behaviour or perception. Among the most prevalent of these are d-lysergic acid diethylamide, or LSD-25, which originally was derived from ergot (Claviceps purpurea), a fungus on rye and wheat; mescaline, the active principle of the peyote cactus (Lophophora williamsii), which grows in the southwestern United States and Mexico; and psilocybin and psilocin, which come from certain mushrooms (notably two Mexican species, Psilocybe mexicana and P. cubensis).
Other hallucinogens include bufotenine, originally isolated from the skin of toads; harmine, from the seed coats of a plant of the Middle East and Mediterranean region; and the synthetic compounds methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), and phencyclidine (PCP). Tetrahydrocannabinol (THC), the active ingredient in cannabis, or marijuana, obtained from the leaves and tops of plants in the genus Cannabis, is also sometimes classified as a hallucinogen.
Historical use and early scientific interest
Historically, native societies of the Western Hemisphere utilized plants containing psychedelic substances. The hallucinogenic mushrooms of Mexico were considered sacred and were called “god’s flesh” by the Aztecs, and during the 19th century the Mescalero Apaches of the southwestern United States practiced a peyote rite that was adopted by many of the Plains tribes. Peyotism eventually became fused with Christianity, and the Native American Church was formed in 1918 to protect peyotism as a form of worship.
Scientific interest in hallucinogens developed slowly. Mescaline was finally isolated as the active principle of peyote in 1896. It was not until 1943, when Swiss chemist Albert Hofmann accidentally ingested a synthetic preparation of LSD and experienced its psychedelic effects, that the search for a natural substance responsible for schizophrenia became widespread. Gordon Wasson, a New York banker and mycologist, called attention to the powers of the Mexican mushrooms in 1953, and the active principle was quickly found to be psilocybin.
Only the d-isomer of LSD was found to be psychedelically active. It was thought that LSD, as well as psilocybin, psilocin, bufotenine, and harmine, acted antagonistically toward serotonin, an important brain amine. However, evidence for this was contradictory. Some chemicals that blocked serotonin receptors in the brain were found to have no psychedelic activity. Mescaline was discovered to be structurally related to the adrenal hormones epinephrine and norepinephrine—catecholamines that are very active in the peripheral nervous system and are suspected of playing a role as neurotransmitters in the central nervous system.
Psychotherapy and illicit use
During the 1950s and ’60s there was a great deal of scientific research with hallucinogens in psychotherapy. LSD was used in the treatment of alcoholism, to reduce the suffering of terminally ill cancer patients, and in the treatment of children with autism. Controversy arose over the social aspects of the drugs. Subsequent scientific research indicated that the side effects of these drugs were more serious than previous research had indicated and that human experimentation was somewhat premature. As a result, many of the hallucinogens were limited to scientific use, with pharmaceutical manufacture strictly regulated.
Illicit experimentation continued over the following decades, partly inspired by the mystical writings of Aldous Huxley, and a vigorous subculture sprang up surrounding hallucinogens in the 1960s. Originating on the West Coast of the United States, it spread throughout North America, Western Europe, and Australia. At the end of the century there was a revived interest in LSD in the United States, and the drug Ecstasy became popular among young people. In addition, some individuals began experimenting with countless new substances, particularly from the phenethylamine and tryptamine families, which was difficult to regulate or suppress because the necessary information to make the drugs was widely available through the internet.

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