What Causes Hallucinations?

Published :
Categories : Default

What Causes Hallucinations?

LSD and cannabis can cause hallucinations that can delight or confound. What goes on inside your brain when you are hallucinating, and why does your outlook on the world change?


The question of whether cannabis can cause hallucinations is a topic saturated with anecdotal accounts. There are, of course, several variables to consider, not the least of which is rampant misinformation perpetuated by the global war on drugs. However, dig deeper into scientific studies on the matter, and you'll find that the majority of evidence refutes the possibility of typical cannabis use causing hallucinations.


Such studies do appear, however, to suggest a link between existing mental health conditions (schizophrenia, bipolar disorder, or depression) and an increased risk of cannabis-induced hallucinations. Evidence is still limited, but the advice is clear—anyone with a family history of mental illness should proceed with caution before choosing to consume cannabis.

However, on the opposite end of the spectrum, a 2018 case report in Cannabis and Cannabinoid Research examined the effects of acute cannabis dosing on a healthy male candidate. Not only did they want to establish whether the claim of hallucinations was correct, but also how these effects compared to true hallucinogenic substances such as psilocybin or salvia.

Researchers found that cases of cannabis hallucinations were rare, especially in healthy volunteers. Moreover, their evidence suggests that cannabis-induced hallucinations are fundamentally different from a typical hallucination (one caused by psychedelic substances) because cannabis does not interact with brain receptors in the same way. They also concluded that hallucinations "mostly occurred after administration of purified Δ-9 tetrahydrocannabinol (THC) rather than whole-plant cannabis".

Cannabis Hallucinations


The main takeaway from current data is that the possibility of cannabis-induced hallucinations is incredibly low. It's important to remember that many of these studies used a small sample size, especially when compared to how many people around the world use cannabis. Thus, providing a definitive answer still requires further investigation. Add in the complication of synthetic THC, a substance with extreme effects, and you can see why the question "Can cannabis cause hallucinations?" has so many people confused!


Hallucinations - often good, sometimes bad - are the hallmark of the psychedelic trip. LSD is a powerful hallucinogen that impacts the human brain in a number of ways. There are direct physical changes which are responsible for the “trip”. Then, there are the indirect, eschatological and personally transformative effects resulting from the trip. Contemporary brain imaging has shown the former, while contemporary psychiatry is excited by the latter. But exactly what is a hallucination, and what causes it?


Neurotransmitters are chemicals in the brain that help transmit and modulate information. These chemicals bind to a site by using a key (neurotransmitter) that unlocks a lock (receptor). This lets the brain know that information has been exchanged. This information is released as an electrical signal that lets another part of the brain know that this part was activated.

Taking LSD, as well as most other hallucinogens, affects the serotonin system in the brain. Serotonin is present in the bowel, blood platelets, and the brain, and is active in constricting smooth muscles, regulating cyclic body processes, and contributing to overall wellbeing and happiness. Most notably in regard to tripping, serotonin is an important neurotransmitter. Serotonin is used extensively when processing vision and emotions. It is also used to a lesser degree when processing the other senses.

80-90% of serotonin is manufactured in the gastrointestinal tract and plays an important role in digestion. Interestingly, this serotonin stays in the intestines; the serotonin used by the brain must be made by the brain. Serotonin (5-hydroxytryptamine or 5-HT) is synthesised within the body from the proteinogenic amino acid tryptophan.

LSD Hallucination


It sounds like the latest cool name for a superhero from DC or a quantum state in computing. In reality, hyperconnectivity is the state that LSD causes in the human brain. To lesser or greater degrees, hyperconnectivity between different parts of the brain is what comprises a trip. Full sensory hallucinations and alterations in perception, as well as enhanced feelings of emotion are all outcomes of hyperconnectivity.

Through a relatively unknown mechanism, LSD causes cross-chatter between previously unconnected parts of the brain. In the long-term, this can actually build new neural pathway, like putting in new optical fibre networks. This cross-chatter often results in synesthesia, a phenomenon where one sense is perceived by additionally senses. “Seeing sound” and “feeling light” are not uncommon while on LSD.

Images of the brain under the influence of LSD show remarkably increased activity throughout the whole brain. Regions normally isolated start to communicate with each other. For example, more regions of the brain than normal contribute to visual processing. Simultaneously, other parts of the brain become less connected. The breakdown of these networks is thought to be responsible for the feeling of “oneness” that many psychonauts report.


Usually about thirty minutes after consuming, the effects of LSD start to come on. LSD uses a chemical key that mimics the one serotonin uses to connect to a nerve cell. In fact, LSD is actually more efficient at activating these receptors than serotonin itself. Essentially, LSD increases the amount of signalling normally caused by serotonin. This is done via a number of actions not limited to binding. Extra serotonin is released, and it changes the locks to suit more keys, more readily.

Taking LSD is like turning the volume up on a piece of music. The audible pieces are still audible; then all the whispers and background noises can be heard that couldn’t be observed previously. Because the signal is increased, so is the signal noise. If you turn up a speaker too loud, annoying hisses and feedback loops can occur. Also when the volume is too high, it is difficult to distinguish between loud sounds. With LSD, this results in hallucinating visual, aural, and tactile things that aren’t really there.

It isn’t really understood how the mechanism of cognition works, that thing that makes us think the way we do. All we know is what it does thanks to complex imaging machines. It also isn’t yet understood how LSD and the other serotonergic hallucinogens (including ecstasy) change one’s mindset. All we know is that these substances can be quite profound and at times, life changing.


Bicycle Day is celebrated every year on April 19th. And for good reason. It salutes the day Dr. Albert Hofmann first experienced LSD and realised he had discovered a tool to help human beings be what they can truly be. Dr Hofmann insisted until his death that LSD and the associated states of wellbeing therein could help create positive changes in society.

Albert Hofmann

LSD does shift the paradigm of thought and is often considered to help individuals think “outside the box”. Increased serotonin has a euphoric effect and seems to increase the ability to feel empathy for others. Higher levels of empathy also influences how you think in general about the world at large.

It should be noted that there are no proven addictive mechanisms in LSD. Additionally, casual use is not associated with causing brain damage. Any use will reduce serotonin levels following the trip, but one or two weeks of abstinence will return levels to normal. And remember, LSD is a powerful drug and can still be used recklessly. So please, be careful out there.