Cannabis Induced Psychosis – Symptoms, Causes, and How to Treat It

Cannabis induced psychosis

Although it isn’t classified as an illness, psychosis is a serious mental condition that requires attention.

When talking about psychosis triggered by the use of cannabis, it’s important to note that this acute state can manifest with severe symptoms, but will usually resolve once the drug is out of the system.

However, the scientific research done in the field presents a pretty strong consensus. There is no room for controversy: a psychotic episode should be an immediate warning sign to stop marijuana abuse.

People with a psychological susceptibility to mental disorders should avoid any substance abuse, including cannabis.

In some cases, this type of proneness is also connected with a higher risk of developing complex illnesses such as schizophrenia or bipolar disorder, especially if there is a genetic predisposition.

In this article, we’ll try to sum up the latest studies that exploit this subject and bring you the essential facts you should know about cannabis induced psychosis.


When experiencing a psychotic episode while high, an individual is always separated from reality in some form. Different manifestations include:


A delusional person has false beliefs, despite strong evidence that speak otherwise. Common delusions in marijuana induced psychosis are paranoia, extreme suspicion, and a sense of grandiosity (believing that you can do more than you are capable of).


One perceives things that contradict reality via different senses (visual and auditory are the most usual).

Dissociation from the real world

Dissociation is a sense of being detached from reality. It can manifest as depersonalization (having a feeling that you are outside of your body) and derealization (believing that objects around you are not real).

 Inability to organize thoughts

Another manifestation is having disturbing thoughts and little control over them, followed by a difficulty to focus and speak in a rational order.

Emotional extremes and behavioral changes

If the above are present in a psychosis episode, a person typically has exaggerated effects, characterized by anger and agitation, or, on the other end of the spectrum, by a lack of any effect whatsoever (catatonic behavior).

Although it doesn’t necessarily mean that a psychotic is dangerous, many of these symptoms can lead to risky behavior.

For example, paranoia can trigger the need to defend oneself, which could end up in an over-aggressive attitude. A delusion of grandiosity can immerse a person in actions that are potentially self-harming.

Naturally, in these cases, it is crucial to seek help and prevent further accidents.


Typically, marijuana-induced symptoms emerge without much warning. But there can be some indications, which are defined as a pre-psychosis or early psychosis. Some of the signs are:

  • Depression
  • Anxiety
  • Paranoia
  • Withdrawal
  • Inappropriately strong emotional reactions
  • Emotional indifference
  • Inability to formulate logical speech

Is cannabis induced psychosis permanent?

As we said, the psychotic state introduced by weed is usually acute and has a limited duration (during consumption, withdrawal, or a month after it). Once the THC has left one’s system, the symptoms should disappear.

Nevertheless, this type of individual reaction could implicate vulnerability to mental disorders, thus having a chance to reoccur. People reported repeated psychotic episodes each time they smoked weed.

In some cases, usually with an underlying mental disease, the episodes can develop into a chronic state that requires complex medical treatment.

What causes cannabis induced psychosis?

Delta-9-tetrahydrocannabinol (THC) is well-known for its psychotomimetic effect. This component of cannabis can produce symptoms similar to those found in “real” psychosis, which are characteristic of schizophrenic fits, for example.

THC interferes with the normal functioning of the brain by disrupting the flow of signals among its cells, normally regulated by endocannabinoids, explained Beat Lutz, a neurochemist at the University of Mainz. Upsetting this vital flow of information produces depression, anxiety disorders, epileptic fits, and psychosis.

Curiously enough, the other component of cannabis – Cannabidiol (CBD) appears to have the opposite effect. Scientists are researching its possible usage as an antipsychotic drug.

Professor Philip McGuire, from King’s College London’s Institute of Psychiatry, Psychology, and Neuroscience, was the lead author of the study that aimed to explore alternatives to conventional antipsychotic drugs.

His trial showed a modest improvement in the condition of patients that were simultaneously using their antipsychotic therapy and CBD, thus pointing to the possibility that this component could offer additional benefit in such treatment.


According to research done in the past decade, a higher risk for developing substance induced psychosis depends on three factors:

Susceptibility to mental disorders

This is another critical consensus among scientists: people who are mentally “vulnerable” in some way are more likely to develop a psychotic episode while using pot. For example, if a person has a family history of schizophrenia, and is using cannabis, he or she will most probably undergo such condition sooner or later.

In such cases, David J. Castle from the Department of Psychiatry at St Vincent’s Hospital Melbourne, comments in his study Cannabis And Psychosis: What Causes What?, that  THC acts as a cumulative causal factor. In other words, it could be one of the reasons the illness manifests itself.

To people who are predisposed to mental illnesses, even a small dosage could provoke psychotic state. It is as if someone with diabetes would eat sugar and become hyperglycaemic. (Castle, 2013)

THC potency and dosage

It is often claimed that weed is stronger these days, in comparison to its potency back in the seventies. The United States is the only country that has analyzed the THC content of cannabis products over the past three decades.

The data in those analyses “show an increase in THC content from 1.5% in the early 1970s, to 3.3% in the mid-1980s, and 4.4% in 1998.”

Marijuana is not what it used to be.

This begs the question if the current THC potency is somehow related to the statistical rise in the number of reported psychotic episodes during consumption.

Although the science doesn’t come to a final word on the matter, it seems that there is a close correlation between THC potency and dosage, and the development of psychotic behavior.

In an interview given at the World Psychiatric Association’s World Congress in Berlin, results of a recent research study were presented, showing that high-potency cannabis (approximately 16 percent THC) was involved in 24 percent of all cases of the first episode of psychosis.

The connections behind the issue and the conclusions seem pretty obvious.


Besides the increased risk recognized in individuals prone to mental disorders, variants of a particular gene might also be responsible for cannabis induced psychosis.

A study conducted in 2016 showed that people who experienced the onset of psychotic symptoms for the first time also had specific variants of an AKT1 gene. The scientists were observing a group of 442 young cannabis users getting high and collected their DNA samples to perform an in-depth forensic analysis on them.

They learned that people with the AKT1 variant might release excess dopamine when they smoke cannabis, thus increasing the risk of psychotic symptoms.


Even though one might feel reluctant to do so, it is essential for a person with psychotic symptoms to seek medical help. The experts recommend detoxification, providing a safe and quiet environment for recovery, and possibly, antipsychotic medications.

Considering that marijuana induced psychosis can sometimes indicate more severe disorders, medical advice and ongoing care could be vital. Psychiatric screening in such cases might discover illnesses timely, leading to proper preventive responses.

Final word

It’s tempting to think of cannabis induced psychosis as a one-time occurrence that will never happen again.

It’s probably frightening to seek help.

In most cases, it’s undoubtedly hard to quit.

But science, together with the experience of others, spells it out loudly and clearly: call it quits and ask for advice. It can happen again.


  • Castle, D. J. (2013, January 11). Cannabis and psychosis: what causes what? F1000 Faculty Reviews.
  • Degenhardt L, H. W. (2016, August 9). Is Cannabis Use a Contributory Cause of Psychosis? Can J Psychiatry.
  • Fields, R. D. (2017, October 20). Link between Adolescent Pot Smoking and Psychosis Strengthens. Scientific American.
  • Morgan, C. J. (2016, February 16). AKT1 genotype moderates the acute psychotomimetic effects of naturalistically smoked cannabis in young cannabis smokers. Translational Psychiatry volume 6.Philip McGuire. (2017, December 15). Cannabidiol (CBD) as an Adjunctive Therapy in Schizophrenia: A Multicenter Randomized Controlled Trial. American Journal of Psychiatry.
About the author
Helena Miles

Experienced journalist with a decade-long experience of researching cannabis. She has been featured in many prominent outlets, such as The Growth Op, National Post and The Province.

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