The psychedelic effects of cannabis: A review of the literature

Abstract

Cannabis and classic psychedelics are controlled substances with emerging evidence of efficacy in the treatment of a variety of psychiatric illnesses. Cannabis has largely not been regarded as having psychedelic effects in contemporary literature, despite many examples of historical use along with classic psychedelics to attain altered states of consciousness. Research into the “psychedelic” effects of cannabis, and delta-9-tetrahydrocannabinol (THC) in particular, could prove helpful for assessing potential therapeutic indications and elucidating the mechanism of action of both cannabis and classic psychedelics. This review aggregates and evaluates the literature assessing the capacity of cannabis to yield the perceptual changes, aversiveness, and mystical experiences more typically associated with classic psychedelics such as psilocybin. This review also provides a brief contrast of neuroimaging findings associated with the acute effects of cannabis and psychedelics. The available evidence suggests that high-THC cannabis may be able to elicit psychedelic effects, but that these effects may not have been observed in recent controlled research studies due to the doses, set, and settings commonly used. Research is needed to investigate the effects of high doses of THC in the context utilized in therapeutic studies of psychedelics aimed to occasion psychedelic and/or therapeutic experiences. If cannabis can reliably generate psychedelic experiences under these conditions, high-THC dose cannabis treatments should be explored as potential adjunctive treatments for psychiatric disorders and be considered as an active comparator in clinical trials involving traditional psychedelic medications.

Naturalistic use of psychedelics does not modulate processing of self-related stimuli (but it might modulate attentional mechanisms): an event-related potentials study comparing non-users and experienced users of classic psychedelics

“…Further, we were also unable to match groups in terms of the frequency of cannabis use. Cannabis and THC are known to induce robust altered states of consciousness, including experiences of oceanic boundlessness, ego-dissolution, and disembodiment (Zaytseva et al, 2019;Murray & Srinivasa-Desikan, 2022;Murray et al, 2024;Wolinsky et al, 2023). Therefore, in order to control for the confounding effect of both meditation practice and cannabis use, we employed a statistical weighting approach that reduced the impact of data from participants with extensive meditation experience and history of cannabis use (similarly to our previous study in the same cohort; Orłowski et al, 2023).…”

Is Use of Psychedelic Drugs a Risk or Protective Factor for Late-Life Cognitive Decline?

“…Over 30 million people in the United States have consumed classic psychedelics, such as psilocybin, LSD, or mescaline ( Krebs & Johansen, 2013 ). Research suggests some other substances also produce similar hallucinogenic effects and considered as atypical psychedelics, such as marijuana/cannabis ( Wolinsky et al, 2024 ). Further, it is evidenced that some antidepressants, such as St John’s wort ( Ferrara et al, 2017 ; Gurok et al, 2014 ) and Fluoxetine ( Webb & Cranswick, 2003 ), and some tranquilizers ( Kadriu et al, 2021 ) also produce some hallucinogenic effects.…”

“…Multiple studies have shown that classic psychedelics (e.g., psilocybin and LSD) and atypical psychedelics (e.g., cannabis) may be useful in treating mental and neurocognitive disorders due to their ability to stimulate neurogenesis, produce neuroplastic changes, and reduce neuroinflammation ( Vann Jones & O’Kelly, 2020 ; Vollenweider & Preller, 2020 ; Wolinsky et al, 2024 ). Neuroinflammation is significantly associated with the development of Alzheimer’s disease and is considered the most common form of dementia ( F. Zhang & Jiang, 2015 ).…”

A Systematic Review of the Neurocognitive Effects of Psychedelics in Healthy Populations: Implications for Depressive Disorders and Post-Traumatic Stress Disorder

“…Cannabis and MDMA are not traditionally classified as classic hallucinogens; however, they share some pharmacological properties and mechanisms of action with hallucinogenic substances. Endogenous cannabinoids have been found to modulate serotonin, gamma-aminobutyric acid, and glutamate release [ 19 ], whereas MDMA releases serotonin from presynaptic 5-HT terminals and is a potent releaser of dopamine and noradrenaline [ 20 ]. While there is no consensus upon a classification of cognitive functions, a proposed taxonomy categorizes cognition with emotional valence as “hot cognition” (e.g., anhedonia, negativistic rumination), which differs from “cold cognition” (e.g., learning, memory, executive function, information processing speed, attention/concentration) [ 21 ].…”