What Are Hallucinogens?

Explore the history and cultural significance of psychedelics, including their use in indigenous traditions, their role in contemporary medicine, and why terming them “hallucinogens” could be misleading. 

Overview: The terms “hallucinogen” and “psychedelic” are often used interchangeably, but they have different meanings. While hallucinogens create visual and auditory hallucinations, psychedelics generally do not. Psychedelics produce a range of perceptual and cognitive effects, leading to altered states of consciousness and potential therapeutic benefits. They interact with the 5-HT2A receptor in the brain to produce their effects. Examples of psychedelics include LSD, psilocybin, and DMT. The term “hallucinogen” may be misleading as it implies the drugs induce hallucinations, which is not entirely accurate. The term “entheogen” emphasizes the spiritual and therapeutic aspects of psychedelics. Tropane alkaloids, such as those found in belladonna, can cause hallucinations and delirium and are an exception to the general characteristics of psychedelics. Further research is needed to fully understand the effects and potential applications of psychedelics in medicine and mental health.

Exploring the Difference: Hallucinogens and Psychedelics

The terms “hallucinogen” and “psychedelic” are often used interchangeably. To this day, psychedelics are sometimes referred to as hallucinogens in peer-reviewed scientific papers, but it's important to note that these terms have different meanings.

When most people use the term “hallucinogen,” they are usually referring to psychedelics. While both hallucinogens and psychedelics can produce a range of changes in perception, cognition, mood, and more, “hallucinogen” refers explicitly to drugs that create visual and auditory hallucinations. Psychedelics, for the most part, don’t do that. This important distinction will be elaborated on below. 

What Are Psychedelics?

Psychedelics are a class of non-addictive psychoactive drugs that have been used for thousands of years in various cultures and traditions around the world, often for spiritual or medicinal purposes. Examples include the use of ayahuasca by indigenous tribes in South America, psilocybin mushrooms by indigenous peoples in Central America, and peyote by Native American tribes in North America.

In shamanic contexts, the altered states of consciousness induced by these substances are often considered sacred and used in religious ceremonies to facilitate communication with spirits, enhance creativity, and promote healing.

Psychedelics certainly produce altered states of consciousness. However, these states are not necessarily characterized by “hallucinations” in the traditional sense of the word.

Instead, psychedelics can produce a range of perceptual and cognitive effects, such as distortions of visual perception, changes in the experience of time, and shifts in emotional or spiritual awareness. Such experiences often lead to improved mental health and profound changes in the way we think about and experience the world.

It's important to note, however, that psychedelic experiences can be highly subjective and differ from person to person. Additionally, the effects of psychedelics can be highly unpredictable, and, although rare, some people may experience negative side effects or adverse reactions.

To minimize the probability of a difficult experience, it is important to approach psychedelics with caution and to use them in a safe and controlled environment, making sure to heed the guidelines of set and setting

How Do Psychedelics Work?

Psychedelics interact with various receptors in the brain, the primary being a subtype of the serotonin receptor family called the 5-HT2A receptor, sometimes called the serotonin 2A receptor, to produce psychedelic effects. 

This receptor is found in high densities in the prefrontal cortex, and is believed to be essential for eliciting the psychedelic experiences produced by the family of so-called “classic psychedelics,” which includes lysergic acid diethylamide (LSD), psilocybin (the psychoactive component of magic mushrooms),  N, N-Dimethyltryptamine (DMT), 5-MeO-DMT, and mescaline

When psychedelics bind to the 5-HT2A receptor, it triggers a cascade of biochemical reactions that ultimately produce profound alterations in neural activity throughout the brain which change the structure and dynamics of the world we experience. This alteration in brain activity is believed to be involved in the range of effects that typically characterize a psychedelic experience, which often includes distorted perception of time, space, and reality, sensory enhancement, and intensified emotions.

Moreover, psilocybin has been found to increase the functional connectivity between brain regions involved in emotion processing. This may explain the intense emotional experiences often reported during the psychedelic experience.

While the precise mechanisms by which psychedelics produce their effects are still not fully understood, the role of the 5-HT2A receptor seems to be a crucial piece of the puzzle. Understanding how these drugs interact with the brain can help shed light on their potential therapeutic uses and guide future research into their effects.

Examples of Psychedelics 

LSD: If you've heard of hallucinogens or psychedelics, chances are you've heard of LSD. First synthesized in 1938 by Swiss chemist Albert Hofmann, LSD has been the subject of intense scientific and cultural interest since.

LSD interacts with a range of serotonin, dopamine, and adrenergic receptors in the brain, leading to a wide range of subjective effects. These can include vivid geometric visuals, deeply felt positive mood, altered perceptions of time and space, and mystical feelings of unboundedness and oneness with the universe.

In clinical studies conducted between the 1950s and 1970s, LSD showed meaningful potential to treat pain, anxiety, depression, alcohol use disorder, and heroin use disorder until research was strictly prohibited. Clinical LSD research has resumed in recent years, where the drug’s potential to aid in the treatment of anxiety and alcohol use disorder has again been observed, though further research is required. 

Psilocybin: As stated above, psilocybin is the chemical compound that puts the magic in magic mushrooms. Like LSD, psilocybin is an agonist of the 5-HT2A receptor, producing a range of similar psychedelic effects, and it has been shown to reliably produce mystical-type experiences of profound spiritual significance and personal meaning. 

Psilocybin has also demonstrated promising therapeutic potential over the past decade, with several clinical trials indicating a robust antidepressant and anxiolytic effect in treatment-resistant patients, as well as anti-addictive effects in people addicted to tobacco and alcohol. Though research thus far looks quite promising, there is a need for more clinical trials with larger sample sizes that will be more representative of the population at large. 

DMT: DMT, on the other hand, is a naturally occurring psychedelic found in many plants and animals, including humans. However, its biological function in humans is unknown and, as a consequence, remains the subject of much interesting speculation.

DMT is a short-acting 5-HT2A receptor agonist that is rapidly metabolized by the body which, when smoked or vaporized, results in a relatively short psychedelic experience lasting approximately 5-20 minutes. Despite its brevity of effects, DMT can produce very intense perceptual and sensory experiences in which the structure and dynamics of one’s experienced world are seemingly transformed.

DMT users often describe being catapulted into what feels like an otherworldly state of consciousness, colloquially referred to as “hyperspace.” The features of hyperspace vary from person to person, but some common experiences reported by DMT users include vivid, complex, and highly detailed visual imagery and geometric patterns, fractals, and mandalas, while others describe encounters with seemingly intelligent alien beings, entities, or spirits.

DMT is also one of the main ingredients in the Amazonian visionary tea, ayahuasca, where its combination with monoamine oxidase inhibitors (MAOIs) — compounds that inhibit the activity of the enzyme that rapidly breaks DMT down — prolongs the experience to approximately 4-6 hours.  

Is the Term “Hallucinogens” Misleading? 

The term “hallucinogens” has been used for a long time to describe psychedelics. However, it may be misleading.

Hallucination typically refers to the perception of something that is not present or does not exist, such as seeing or hearing things that are not really there. Arguably, in using the term hallucinogen, one suggests that psychedelic substances can make people see things or hear things that are wholly divorced from reality, that do not exist. 

This doesn’t seem to be the case, however. Although psychedelics can produce perceptual distortions, illusions, and complex closed-eye visuals, they do not induce true hallucinations, that is, hallucinations that seamlessly blend in with the surrounding environment. 

Unlike hallucinations, the effects of psychedelics are based on actual sensory input coming from the environment. Also, under the influence of psychedelics, users maintain insight into their psychedelic-induced state of consciousness and maintain awareness that the visuals they experience are distinct from the normal waking world. 

“The inducement of hallucinations is a property that is commonly attributed to psychedelics, but in reality is virtually non-existent in the use of such materials. In almost all psychedelic experiences undergone by normal healthy people, there is an awareness of real surroundings. Visual distortions are common, but they are not confused with objective reality.”

- Ann Shulgin, writer and pioneer of psychedelic therapy. 

To some, the term “hallucinogen” may sound like the proper scientific term, while “psychedelic” carries with it substantial countercultural or new-age baggage.

While, by others, the term “hallucinogen” has been used to stigmatize and demonize mind-altering substances, being employed to describe dangerous, hard-to-control drugs that make people hallucinate. Such use of this label implies that the experiences induced by psychedelics are pathological, unreal, or invalid, and disregards their potential for producing meaningful, spiritually significant, therapeutic, and self-transcending experiences.

Taken together, “psychedelic” seems to be the most accurate term for encompassing the broad range of perceptual and sensory experiences, cognitive effects, insights, and emotions that are commonly experienced. 

In place of both “hallucinogens” and “psychedelics,” some prefer the term “entheogen,” derived from the ancient Greek terms “éntheos” and “genésthai,” roughly meaning to create God within. Coined by author and classical studies professor, Dr. Carl Ruck, “entheogen” emphasizes the potential of these substances to inspire experiences of a religious or spiritual nature, particularly in sacred contexts.

“In a strict sense,” says Ruck, “only those vision-producing drugs that can be shown to have figured in shamanic or religious rites would be designated entheogens, but in a looser sense, the term could also be applied to other drugs, both natural and artificial, that induce alterations of consciousness similar to those documented for ritual ingestion of traditional entheogens.”

Ruck and colleagues preferred entheogen to psychedelics due to the latter’s similarity in sound to words relating to psychosis and also because of its association with the 1960s counterculture. Some argue that “entheogen” is too closely linked to religion and prefer the more neutral term “psychedelic” which simply means “mind-manifesting.”

Ultimately, the choice of terminology can vary depending on personal preferences and cultural contexts.

Tropane Alkaloids: Hallucinogenic Psychedelics? 

One notable exception of psychedelic-like compounds that do reliably produce true hallucinations, and for whom “hallucinogen” could arguably be an appropriate term, are the “deliriant” psychedelic tropane alkaloids. These alkaloids are mainly found in plants belonging to the family Solanaceae, which includes plants such as belladonna, jimsonweed, mandrake, and henbane. 

Some of the most well-known tropane alkaloids include atropine, hyoscyamine, and scopolamine. These compounds have been used for centuries across the world for a variety of purposes, from healing and divination to mere recreation. Unlike 5-HT2A agonist classic psychedelics, tropane alkaloids act as antagonists of the M1 subtype of the muscarinic receptor, blocking the binding of the neurotransmitter acetylcholine. 

Tropane alkaloids can produce states of altered consciousness that are similarly unusual to those produced by classic psychedelics such as LSD and psilocybin. However, the nature of these states is distinctive. Unlike with classic psychedelics where the user is aware that what they are experiencing is distinct from normal reality, tropane alkaloids can cause true hallucinations and delirium. 

Also, depending on their dose, tropane alkaloids can have both therapeutic and toxic effects. At low doses, they can be used to treat a variety of conditions such as asthma, gastrointestinal disorders, and motion sickness. However, at high doses, they can cause serious adverse physical effects.

While the term “hallucinogen” may be considered by some to be somewhat misleading in describing the full range of effects of psychedelic substances, it is commonly used to refer to these drugs. 

In recent years, psychedelics have been the subject of increasing research due to their potential therapeutic benefits for conditions such as depression, anxiety, and addiction. That said, there is a need for further research to more comprehensively understand associated risks, mechanisms of action, and potential applications in medicine and mental health.

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