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Introduction to the "Classical" Psychedelics

Introduction to the "Classical" Psychedelics


Psilocybin is a psychedelic molecule produced by over 100 mushroom species. Many of these species are found in Mexico where psilocybin-producing mushrooms have been consumed traditionally for centuries. Psilocybin’s chemical structure shares many similarities with serotonin, a mood-regulating molecule produced in the human body. The psilocybin experience generally lasts for around 6 hours. Psilocybin is currently being researched as a potential treatment for depression, substance use disorders, anxiety, obsessive compulsive disorder, anorexia, migraine headaches, amongst others. Psilocybin mushrooms are usually eaten or made into a tea, and the psilocybin being used in clinical trials is chemically synthesized in a lab and consumed in the form of a pill.

Dimethyltryptamine (DMT)

DMT is a molecule found in many plants around the world. It has also been detected in rodent brains, and some scientists think that the human brain might produce DMT as well. DMT on its own does not have psychedelic effects when consumed orally, so many people smoke it. When smoked, the experience only lasts for about 15 minutes. Early animal studies and reports from people who have used DMT suggest the molecule might have potent antidepressant and anti-anxiety effects. If these effects are confirmed in larger controlled studies, the short duration of the DMT experience would make it especially useful in a clinical setting.

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT)

5-MeO-DMT is found in some plants and in secretions of the Sonoran Desert Toad. As with DMT, 5-MeO-DMT is generally smoked and the experience tends to be short. Also similar to DMT, preliminary studies with 5-MeO-DMT for depression and anxiety are promising, but more work needs to be done to compare the effects of 5-MeO-DMT to more well-studied psychedelics such as psilocybin.


Mescaline is a molecule found in many species of cacti. These cacti are made into a brew which people drink in a ritualistic setting often with chanting and drumming. Cacti containing mescaline have been used for thousands of years in the Southern United States, Central America, and South America. The experience often lasts 10 or more hours. Despite its rich history, mescaline has been the topic of very few clinical studies. The length of the mescaline experience would make it difficult to work with this molecule in a clinical setting.


Ayahuasca is not a single molecule or plant. It’s a complex mixture of different ingredients that has been used for over 1000 years in South America. Caapi, also known as yage, is a vine that contains harmala alkaloids, a group of molecules that prevents the body from rapidly breaking down DMT. This vine is generally mixed into a brew with one or more plants that contain DMT. DMT is not normally psychedelic if you eat or drink it because the body breaks it down so quickly. In combination with the harmala alkaloids from the caapi vine, the body can’t easily break it down, and so it can make its way to the brain and exerts its psychedelic effects.

Because the composition of the brew varies so much, the experience also varies and as a result its likelihood for use in western medical applications is low. It tends to be long (more than ten hours) and highly visual. Ayahuasca retreats are becoming more popular for western tourists, but retreats are not well-regulated so caution is warranted before deciding to visit one. Still, ayahuasca has been shown to have powerful antidepressant effects.


LSD, also known as “acid”, is perhaps the most stigmatized psychedelic. It was originally synthesized in Switzerland in 1938. It was widely distributed and heavily used by the 1960s counterculture but also by psychotherapists who were interested in using LSD as a tool to explore the mind and improve patients’ lives. It is the most potent psychedelic currently known. The experience lasts for about 10 hours. It is similar to the psilocybin experience but generally more stimulating. The stigma associated with LSD in addition to the length of the experience has made it especially difficult for today’s clinicians to study even though it has a host of therapeutic applications.


Ketamine was originally developed in the 1960s as an anaesthetic for use during surgeries. It was officially approved for medical use in 1970, and it found its way to the streets around that time. The psychedelic effects of ketamine have not received the same attention as many of the more commonly used psychedelics like psilocybin and LSD. At the right dose and in the appropriate setting, ketamine can be highly psychedelic. It is a potent, fast-acting antidepressant, and some studies suggest that the antidepressant effects of the molecule come from its psychedelic properties. Ketamine is the first psychedelic to become an approved treatment for depression and it’s helping to pave the way for new molecules and treatment models for psychiatric disorders.

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