From Reefer Madness to Two and a Half Men, many uninformed cultural depictions of weed have portrayed the drug as a powerful hallucinogen. But of all the psychological and somatic effects associated with cannabis use, hallucination is one of the least reported. Is THC’s trippy reputation totally unfounded, or is there some truth to it?
Canna Hashish Cause Hallucinations?
One of the earliest sensationalistic accounts of cannabis-induced hallucination comes from a legend about 11th century Islamic leader Hassan-i-Sabbah. The story, brought back to Europe by Marco Polo and now widely thought to be unfounded, tells of how Hassan-i-Sabbah drugged a group of followers with hashish and brought them to a lush garden filled with beautiful women. Once there, he convinced them that the garden was actually paradise and that the only way they could find it again was to fight in his service.
These newly-converted soldiers were called hashishins, a term that gives us the modern word “assassin.”
Although the etymology and the story itself are disputed, this account of a hallucinatory mind-control drug was powerful enough for it be invoked as an argument for cannabis prohibition in the U.S. in the 1930s.
It’s clear that a sufficient amount of cannabis — especially in a concentrated form like hash — can induce some disorienting sensations. Time can seem to slow down significantly. Sounds can take on exaggerated dimensions, and blips in peripheral vision can be enough to snap a smoker out of couchlock. Compared to reports of full-fledged acid trips or DMT experiences, though (breathing walls? machine elves???), such distortions in perception from cannabis feel almost comforting and grounded.
THC vs. Serotonergics
Cannabis and serotonergics — the class of psychedelic substances found in LSD, mushrooms, and mescaline that are more commonly associated with hallucinations — act on the brain in different ways.
The active compounds in cannabis — of which THC is the most psychoactive
bind to receptors on the ends of neurons distributed throughout the body and the brain, altering the way information is transmitted between those neurons. There are high concentrations of these receptors in areas of the brain that regulate movement, appetite, sleep, and higher cognitive functioning; cannabis intoxication can therefore have corresponding effects like impaired coordination, hunger, sleepiness, and, most notably, altered ways of thinking.
Serotonergics, on the other hand, act on serotonin, a chemical in the body that is thought to regulate feelings of happiness. Serotonergics like psilocybin and lysergic acid bind to serotonin receptors in the brain — and do it so well that they actually shut out the body’s own serotonin. Although it’s not precisely understood how these compounds induce hallucination, the fact that they act on the part of the brain that regulates perception may offer a clue. Moreover, recent imaging technology has shown that a person under the influence of LSD in particular uses multiple areas of their brain at once to process vision, instead of just the visual cortex; this may explain why people on a serotonergic psychedelic trip can actually see and hear things that aren’t really there.
Put another way, serotonergics have a more direct and distortional effect on our senses; cannabis just does more to affect the way we perceive and interpret our sensory experiences.
Synthetic cannabis products, a dangerous trend in designer drugs, bind to the brain’s cannabinoid receptors much more strongly than the compounds in natural cannabis. They also lack the antipsychotic properties attributed to natural cannabinoids. This unmitigated, sky-high potency, not present in earth-grown bud, may be responsible for the intense hallucinations and violent behavior associated with synthetic cannabis.
Hallucinations Caused By Genetics
Of course, not all hallucinations are the result of drugs. People with schizophrenia can experience powerful visual, auditory, and even olfactory hallucinations, which can lead to paranoia, isolation, or impaired functioning in the world at large. Schizophrenia is thought to be caused by a disturbance in neurotransmitters (much like cannabis) and by an actual decrease in the brain’s gray matter. People who have schizophrenic hallucinations are often unable to distinguish them from reality. This sounds remarkably similar to the experiences of people who have gotten too high and remain convinced that their delusions and paranoia are real, all objective evidence and reassurance to the contrary. And in fact, there’s evidence that adolescent cannabis use may play some part in triggering schizophrenia in people who have a genetic predisposition for the disorder.
Neuroscientist and noted psychonaut Oliver Sacks offered some thoughts on deconstructing delusional cannabis experiences in his book An Anthropologist on Mars. Writing about his first experience with weed, he relates that his own hand, when viewed against a blank wall,
“seemed to rush away from me […] until it appeared like a vast hand, a cosmic hand.”
Sacks chalks this impression of tremendous size up to altered visual processing, and the lack of any other visual markers for comparison.
Notably, Sacks experienced this pseudo-hallucination the very first time he got high. Others have described similar sensations during early experiences with cannabis, or with very large or concentrated doses. Cannabis can cause you to notice things that sober people pass over — sometimes those things are ridiculous, but sometimes they actually are profound. It’s possible that a person with a lower tolerance for THC could combine a little bit of sensory distortion with some newfound and intense powers of observation and then creatively interpret the experience as a hallucination.
Who’s to say what definitively constitutes a “true” hallucination, though? Even though absinthe and wormwood have been shown to have no real hallucinogenic effects, they were enough to inspire Toulouse-Lautrec to create some green-tinged and decidedly trippy paintings. In Anthropologist and in many other works, Oliver Sacks, like his psychedelic contemporary Aldous Huxley, defends all forms of perception as valid. Regardless of its intensity or content, a cannabis-induced glitch in the way you see the world can be a uniquely awe-inspiring (if not always fun) experience.
Pollan, Michael. The Botany of Desire: A Plant’s-eye View of the World. New York: Random House, 2001. pg. 129.
Sacks, Oliver. An Anthropologist on Mars. New York: Vintage, 1996.