• Classification: Hallucinogen
  •  CSA Schedule: Schedule I
  • Trade or Other Names: • PCP: Angel Dust, Embalming Fluid, Killer Weed, Supergrass
    • MDMA: E, Ecstasy Eve, Go, Hug Drug, Lover’s Speed, Peace, STP, X, XTC
    • LSD: Acid, Blotter Acid, Dots, Mellow Yellow, Window Pane
    • Mescaline: Buttons, Cactus, Mesc, Peyoto
  •  Medical Uses: None
  •  Physical Dependence: Low
  •  Psychological Dependence: Possible
  •  Tolerance: Yes
  •  Duration (hours): 1-12
  •  Usual Method: Usually ingested. Also Snorted, Smoked
  •  Possible Effects: Dilated pupils, higher body temperature, increased heart rate and blood pressure, sweating, loss of appetite, sleeplessness, dry mouth, and tremors
  •  Effects of Overdose: Longer, more intense “trip” episodes, psychosis, and possible death, dehydration, heatstroke, heat exhaustion, muscle breakdown, kidney failure, seizures, stroke, heart attacks
  •  Withdrawal Syndrome: Anxiety, depression, flashbacks, cravings, hallucinations, delusions, panic attacks, psychosis, paranoia, tremors

About Hallucinogens

Hallucinogens are a group of substances that have the potential to alter the thinking process and the perception of the physical world and passing of time.

Substances like hallucinogens can be extracted from different plants or they can be easily synthesized into chemicals in laboratories. Most of these drugs have a high potential of abuse and they are generally used for recreational purposes. Among the general population, they are most commonly known as “Psychedelic drugs”.

Hallucinogenic substances have been around since the dawn of human civilization. Around the world, there are many cultures that reported a high use of hallucinogens in order to induce different visions or alter the perception of reality. These substances were also used in prophetic and religious experiments.

Even though there are several hundred types of hallucinogens, the most used and abused ones are manufactured in illegal chemical laboratories.

The Most common known hallucinogens are:

  • Lysergic Acid Diethylamide (LSD)
  • Mescaline
  • Psilocybin
  • MDMA (Ecstasy)

Over the years hallucinogens have been called many different things. Hallucinogens have gone through dozens of name changes for the same chemical compound even. Some researchers have used the term “psychotomimetics” because of the belief that these drugs mimic the symptoms of functional psychoses such as schizophrenia. This usage is rare today; it is now clear that, although intriguing similarities exist, the effects of hallucinogens differ in many respects from natural psychosis. During the 1960s, advocates of hallucinogen use referred to them as psychedelics, a term coined by one of the early LSD experimenters, Humphrey Osmond. Osmond defined a psychedelic as “a mind-expanding or mind-revealing” drug (Stevens, 1987), but whether LSD or other hallucinogens actually possess such properties is controversial at best.

The term hallucinogen itself can be misleading. It does focus attention on hallucinations and other alterations in perception, and indeed most of the drugs in this category generally do produce sensory disturbances or alterations that can be considered hallucinogenic. However, that is certainly not the only effect these drugs produce. Hallucinogens exert profound effects on mood, thinking processes, and physiological processes as well. Hallucinogens alter nearly all aspects of psychological functioning, and the phrase “altered state of consciousness” describes these drugs better than any we have considered.

Additionally, more than 90 different species of plants and many more synthetic agents can produce these kinds of effects (Siegel, 1984). To simplify this complex group of drugs, it is best to divide them on the basis of their effects and mechanisms of action into four different subgroups and looked at separately.

The first and historically most important group is referred to as the serotonergic hallucinogens. This category includes the synthetic compound lysergic acid diethylamide (LSD) and related drugs, such as mescaline (from the peyote cactus) and psilocybin (from certain mushrooms), along with many other less well-known compounds. These drugs all produce vivid visual hallucinations and a variety of other effects on consciousness.

The second class of hallucinogens includes MDA and MDMA (ecstasy), referred to as the methylated amphetamines. As the name suggests, these drugs are structurally related to amphetamine (as is mescaline). MDA and MDMA produce alterations in mood and consciousness with little or no sensory change. Like amphetamine and cocaine, these drugs act on dopamine, norepinephrine, and serotonin synapses, but their effects are most potent on the serotonergic system (Iversen, 2008).

A third class of hallucinogens, called the anticholinergic hallucinogens, is less familiar to most people and includes drugs such as atropine and scopolamine found in plants such as mandrake, henbane, belladonna, and jimsonweed. These drugs produce a dreamlike trance in users from which they awaken with little or no memory of the experience. The drugs in this class act on cholinergic synapses of the brain (Meyer & Quenzer, 2005).

A fourth class of hallucinogens includes phencyclidine (PCP or angel dust) and the related compound ketamine. These are often referred to as the dissociative anesthetics because of their ability to produce surgical anesthesia while an individual remains at least semi-conscious. Dissociative anesthetics are thought to act through a receptor that influences activity of the excitatory amino acid neurotransmitter, glutamate (Balazs, Bridges, & Cotman, 2006).

Finally, one of the most widely used hallucinogens in recent years is salvinorin A, a chemical found in a plant in the sage family (Salvia divinorum) and often referred to as diviner’s sage or just salvia. Almost completely unknown a decade ago, salvia is quickly becoming banned throughout the USA and the rest of the world. Although relatively little is known about salvinorin A, it appears to act differently on the brain from any of the previously known hallucinogens by affecting specialized opiate receptors known as kappa receptors, and therefore it is classified as a kappa hallucinogen.

Origins of Hallucinogen use

The revolution in the drug abuse field that began in the United States in the mid-1960s and continues today came from concern over the use of hallucinogens, particularly LSD. Until the mid-1960s, the use of illicit drugs in the United States largely had been limited to specific populations or subcultures: heroin was used by those in the inner-city; marijuana was used by jazz musicians; and amphetamine and amphetamine extracts were originally used by women who had them prescribed for weight loss. Prescription anti-anxiety agents, including meprobamate and benzodiazepines such as chlordiazepoxide (Librium), also were commonly used at that time.

In the early 1960s, Timothy Leary, then a young psychology instructor at Harvard, began experimenting with hallucinogens, particularly LSD. He claimed that it provided instant happiness, enhanced creativity in art and music, facilitated problem-solving ability in school and at work, increased self-awareness, and might be useful as an adjunct to psychotherapy. Leary popularized this idea on college campuses, coining the phrase turn on, tune in, drop out. When he was not reappointed to the faculty at Harvard, he became a highly publicized self-proclaimed martyr to his cause, and his followers began to proselytize for LSD. Leary’s advocates organized their lifestyle around LSD and developed a subculture of fellow LSD users who shared this common interest. They became devout users of the drug and they would not use other classes of drugs. For example, they would not smoke tobacco, use amphetamine or amphetamine-like psychostimulants or barbiturates, or even drink alcohol.

As usage of LSD increased, subcultures experimenting with LSD began to emerge in many East and West Coast cities. Other hallucinogenic compounds, such as mescaline and psilocybin, began to be taken as well, although LSD remained the most widely used hallucinogen because it was the most readily available on the street.

Musicians, rock music, the hippie lifestyle, and flower children were loosely joined with Leary’s philosophy. There were highly publicized festivals celebrating LSD, such as “The Summer of Love” in the Haight-Ashbury district of San Francisco. Later, younger individuals began to experiment with LSD, and its use began to increase in all socioeconomic groups, particularly among middle-class and affluent youth.

About this time, various adverse reactions began to be recorded from medical centers around the country. The whole phenomenon continued to be widely publicized, and in many cases sensationalized, by the press. The populace reacted with anxiety and fear, worrying that many of the young would soon become acidheads.

Eventually, many of the LSD users began using other drugs besides hallucinogens. This included the extensive use of marihuana, hashish, and, in some cases, methamphetamine or even heroin. Various street drugs that were previously unknown, as well as combinations of new drugs, were consumed. Also, in the search for new drugs with different and improved characteristics, such as more or less euphoric effects, hallucinogenic activity or stimulant properties, longer or shorter duration of action, literally hundreds of so-called designer drugs were synthesized (e.g., DOM, MDMA, DMT).

Concern about drug abuse rose until it finally was perceived as one of the nation’s most pressing problems. Laboratories stopped distributing the drug in late 1966 because of the reported adverse reactions and the resulting public outcry. At that time, all of the existing supplies of LSD were turned over to the government, which was to make the drug available for legitimate and highly controlled research; however, research on humans essentially was discontinued.

Today, LSD remains classified as a Schedule I drug according to the Comprehensive Drug Abuse Prevention and Control Act of 1970. Legally, LSD is regarded as having no currently accepted medical use in the United States, a high potential for abuse, and to be unsafe even when administered by a physician. Nevertheless, black market LSD remains widely available on the street.

How are Hallucinogens consumed


– is ingested orally, snorted, smoked, or injected. When the powder form is snorted or sprinkled on marijuana and smoked, the effects are felt within 2 to 5 minutes and last four to six hours. Users also dip tobacco or marijuana cigarettes in liquid PCP and smoke it as well. PCP can also be put in capsules and swallowed.


– most often available in tablet form and is usually ingested orally, although some users have reported taking it anally (known as “plugging” or “shafting”).


– LSD is a white or clear, odorless, water-soluble crystal that can be crushed into a powder and dissolved. The most common form of LSD is as a liquid that has been transferred onto a small paper square (known as “blotter”) or as a microdot tablet.
– It is also inhaled or injected.


– The peyote cactus contains buttons that can be cut from the root and dried. The buttons can either be chewed or soaked in water to produce an ingestible liquid. Peyote buttons can also be ground into a powder and then smoked cannabis or tobacco.


Effects of Hallucinogens Use

Short-Term Effects

The overall psychological effects of many of the hallucinogens are quite similar; however, the rate of onset, duration of action, and absolute intensity of the effects differ among the specific varieties of this class of drugs.

LSD is one of the most potent hallucinogens known, with severe effects occurring in some individuals even in very low doses. Because of its high potency, LSD can be applied to paper blotters or the backs of postage stamps. The absorption of LSD from the gastrointestinal tract occurs rapidly, with drug diffusion to all tissues, including the brain. The onset of psychological and behavioral effects occurs approximately 60 minutes after oral administration and peaks 2 to 4 hours after administration, with a gradual return to the pre-drug state in 10 to 12 hours.

The first 4 hours are sometimes called a trip. The subjective effects of LSD are dramatic, and can be divided into somatic (dizziness, paresthesias, weakness, and tremor), perceptual (altered visual sense and changes in hearing), and psychic (changes in mood, dream-like feelings, altered time sense, and depersonalization). The somatic symptoms usually occur first. Later, visual alterations are noticed and sounds are intensified. Visual distortions and illusory phenomena occur, but true hallucinations are rare. Dream-like imagery may develop when the eyes are closed, and afterimages are prolonged. Sensory input becomes mixed together, and synesthesia (seeing smells, hearing colors) is commonly reported. Touch is magnified and time is markedly distorted. Feelings of attainment of true insight are common, as is the experience of delusional ideation. Separating one object from another and self from environment becomes difficult, and depersonalization can develop. Emotions become intensified with rapid and extreme changes in affect. Several emotional feelings may occur at the same time. Overall attention, concentration, and motivation are impaired. Several hours later, users sometimes feel that the drug is no longer active, but later they recognize that at that time they had paranoid thoughts and ideas. From 12 to 24 hours after the “trip” there may be some slight let down or a feeling of fatigue. There is no immediate craving to take more drug to relieve this boredom; one trip usually produces satisfaction for some time. The memory of the events that occurred during the “trip” remain after the effects of the drug wear off.

DMT produces effects that are similar to those produced by LSD, but DMT is inactive after oral administration and must be injected, sniffed, or smoked. It has a rapid onset, almost immediately after intravenous administration, and a short duration of action, about 30 minutes. Because of its short duration of action, DMT was once known as the businessman’s LSD (i.e., one could have a psychedelic experience during the lunch hour and be back at work in the afternoon). However, the sudden and rapid onset of a period of altered perceptions that soon terminates is disconcerting to some. DMT has never been a widely, steadily available or popular drug on the streets. The effects of ayahuasca, a psychoactive beverage that contains DMT, last about 4 hours. In contrast to DMT, the effects of DOM have a very slow onset, but it has been reported to last more than 24 hours. Mescaline is approximately two to three orders of magnitude less potent than LSD, and its effects last about 6 to 10 hours, whereas the effects of psilocybin (mushrooms) last about 2 hours.
The hallucinogens also possess significant effects on the central nervous system. LSD produces marked pupillary dilation, hyperreflexia, increases in blood pressure and body temperature, tremor, piloerection, and tachycardia. Some of these autonomic effects of the hallucinogens are variable and might be partly a result of the anxiety state of the user. DMT and ayahuasca also increase heart rate, pupil diameter, and body temperature. LSD also can cause nausea. Nausea and vomiting are especially common after the ingestion of mescaline or peyote.

Long-term Effects

A high degree of tolerance develops to the behavioral effects of LSD after repeated use. Such behavioral tolerance develops very rapidly, after only a few days of daily use, and tolerance is also lost rapidly after the individual stops taking the drug for several days. Because of this rapid development of tolerance, LSD users usually limit themselves to taking the drug once or twice weekly. Cross-tolerance develops between LSD and other hallucinogens, such as mescaline and psilocybin (mushrooms), suggesting a similar mechanism of action. However, cross-tolerance does not develop to other classes of psychotropic agents that are thought to have different underlying mechanisms of action, such as amphetamine, phencyclidine, and cannabis. It should be pointed out that little tolerance develops to the various Central Nervous System effects produced by the hallucinogens. There is no withdrawal syndrome after the cessation of the chronic administration of the hallucinogens.

Chronic adverse reactions include psychoses, depressive reactions, acting out, paranoid states, and flashbacks. The use of LSD has been found to coincide with the onset of depression, suggesting its possible role in the onset of depression in habitual users. Flashbacks are an adverse reaction mentioned by many users where visual impairment is experienced without consuming the drug, sometimes years later. The name given to this phenomena is hallucinogen persisting perception disorder. Only a small proportion of LSD and other hallucinogenic users experience flashbacks. They can occur spontaneously a number of weeks or months after the original drug experience, appear not to be dose-related, and can develop after a single exposure to the drug. During a flashback, the original drug experience is recreated complete with perceptual and reality distortion. Even a previously pleasant drug experience may be accompanied by anxiety when the person realizes that they have no control over its recurrence. In time, flashbacks decrease in intensity, frequency, and duration (although initially they usually last only a few seconds), without the need for treatment in many cases. Flashbacks may or may not be precipitated by stressors or the subsequent use of other psychoactive drugs, such as psilocybin or marihuana. Flashbacks usually can be handled with psychotherapy. An anxiolytic or neuroleptic may be indicated, but probably is as much for the reassurance of the therapist as for the patient. Various pharmacologic agents, such as clonidine (Catapres) or clonazepam (Klonopin), or drug combinations (e.g., fluoxetine and olanzapine), have been found to be useful in the treatment of flashbacks. The exact mechanism underlying this phenomenon remains obscure. Individuals with flashbacks have a high lifetime incidence of affective disorder when compared to non-LSD-abusing substance abusers. LSD users have long-term changes in visual function. For example, a visual disturbance consisting of prolonged afterimages (palinopsia) has been found in individuals several years after the last reported use of LSD.

Psychosis can develop and persist after hallucinogen use, but it remains unclear whether hallucinogen use can cause long-term psychosis, or if it has a role in precipitating the onset of illness. For example, hallucinogens may have a variety of effects in a person who is genetically predisposed to schizophrenia:

• they may cause the psychosis to manifest at an earlier age;
• they may produce a psychosis that would have remained dormant if drugs had not been used;
• they may cause relapse in a person who has previously suffered a psychotic disorder.

There are few if any long-term neuropsychological deficits attributable to hallucinogen use. Chronic personality changes with mood changes and evidence of “magical thinking” can occur after the use of hallucinogens. There is always the risk that such thinking can lead to destructive behavior. The effects of the chronic use of LSD must be differentiated from the effects of personality disorders, particularly in those who use a variety of drugs in polydrug abuse patterns. In some individuals with well-integrated personalities and with no previous psychiatric history, chronic personality changes have resulted from repeated LSD use. Personality changes that result from LSD use can occur after a single experience, unlike other classes of drugs (PCP, perhaps, excepted). In addition, the hallucinogenic drugs interact in a variety of nonspecific ways with the personality, which may particularly impair the developing adolescent. Treatment of chronic hallucinogen abuse can include psychotherapy on a long-term basis to determine what needs are being fulfilled by the use of the drug for this particular person. Twelve-step meetings also might be crucial for reinforcement of the decision to remain abstinent.

There is no generally accepted evidence of brain cell damage, chromosomal abnormalities, or teratogenic effects after the use of the indole-type hallucinogens and mescaline.