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Is Cannabis-Induced Psychosis Real?

The 1936 movie Reefer Madness has a lot to answer for. A group of high school students smokes some marijuana after being lured into the act by evil drug pushers. All it took was a few hits to transform them from mild-mannered teens into criminals. According to the film, the drug caused the users to engage in psychotic behavior ranging from rape to manslaughter.

This anti-cannabis production achieved its goal despite its many inaccuracies; public opinion remained against cannabis for decades. Only in the past few years have polls shifted to illustrate how the majority of Americans favor legalizing marijuana for recreational use.

A study published in JAMA Psychiatry recently illustrated a link between increased cases of schizophrenia and cannabis use disorder. When we reflect on Reefer Madness, is it possible that it encompassed some potential truths? Can marijuana cause psychosis? Let’s see what science has to say and delve into some real-life cases.

Does Cannabis Cause Psychosis?

According to the World Health Organization, about 147 million people, or 2.5% of the world’s population, consume cannabis. Data from the United Nations suggest that over 200 million people use marijuana worldwide. Recent data published in Forbes (see sources below) showed that 1 in 4 Americans, or 25% of US adults, currently consume (or have tried some form of) cannabis in the last 12 months, up 56% from 2018.


When we look at the prevalence of psychosis, 3% of people in the US will experience psychosis at one point in their lives. Therefore, our interest lies in looking into the data to see if there is causation or correlation between cannabis use and psychotic episodes.

What Does the Research Say?

A study led by Dr. Sagnik Bhattacharyya and published in JAMA Psychiatry in January 2012 found something interesting. The researchers discovered that the intoxicating compound THC increases brain processes that result in psychotic symptoms.

Interestingly, CBD, a non-intoxicating compound, counteracted these effects, with the researchers finding that CBD may have the therapeutic potential of an antipsychotic.

Some studies show that THC increases the severity of psychosis symptoms; however, CBD may counteract this.

The study involved 15 healthy men, all of whom were considered occasional cannabis users. The team used MRI scans to look at the subjects’ brains after consuming a pill containing either THC, CBD, or a placebo.

The conclusion was that THC increased the severity of psychosis symptoms; those who took it showed increased prefrontal cortex activity and decreased striatum activity. One theory is that THC changes the brain’s levels of dopamine, a process seen in individuals with psychosis.

Could CBD Help?

What’s interesting is that individuals already predisposed to psychotic symptoms could benefit significantly from high CBD/low THC cannabis.

A study led by Philip McGuire of King’s College London and published in the American Journal of Psychiatry in 2018 focused on 88 patients with schizophrenia. One group received a placebo, while the other consumed 1,000mg of CBD per day over six weeks.

The researchers discovered that those who consumed CBD displayed lower levels of psychotic symptoms. This data represents one of the first well-designed studies looking into CBD use for schizophrenia, illustrating a need for further research based on these positive outcomes.

Cannabis & Psychosis – Real Life Stories

Paul Hunziker works at Family Therapy and Recovery in Renton, Washington. He claims that high-strength cannabis (such as butane hash oil with a THC content of up to 90%) can cause everything from depression to paranoia.

Duane Stone, a mental health specialist from Seattle, had a similar sentiment. Stone claims that people who have never had issues with mental health suddenly started exhibiting symptoms of paranoia and depression within a year or two of using high-potency cannabis.

One of the most tragic stories was that of 19-year-old Levy Thamba Pongi. In March 2014, the teenager consumed six times the recommended dose of a cannabis cookie. He subsequently jumped to his death off a balcony on the fourth floor of a Holiday Inn in Denver. Pongi was an exchange student from the Republic of Congo with no known history of mental illness or drug use.


The cookie contained 65 mg of THC. Employees of the dispensary where Pongi bought it recommended eating only one-sixth and warned it could take up to 30 minutes to feel any effects.

However, after feeling nothing within the stated time frame, Pongi decided to eat the entire cookie. Two and a half hours later, he jumped from the balcony. It was the first death attributed to marijuana in Colorado since it became legal for recreational use. The problem here is that, because Pongi was from the Congo, data related to his medical and mental health history remain unclear.

Before he jumped from the balcony, he reportedly told friends: “This is a sign from God that this has happened, that I can’t control myself. It’s not because of the weed.” With stories like this, cannabis remains a topic of contention when speaking to the effects on mental health.

A Close Call

Another real-life account of marijuana-induced psychosis involves a young man by the name of Devan Fuentes. Fuentes had never been a habitual marijuana smoker in his adolescent years; however, he was introduced to cannabis in his early twenties. Within just a year or two, he began smoking four to five joints a day.

However, as he increased his consumption, something became clear to him. Instead of the cannabis relaxing or mellowing him out, it enraged him and revved up psychotic delusions and impulses.

After around a year of heavy use, things got bad. Devan began furiously scribbling his thoughts on pieces of paper before throwing them against a wall in frustration. He walked in and out of his house several times before accidentally locking himself out. Eventually, Devan decided to hand over his supply to a neighbor, understanding that it may be contributing to his psychosis.

Those with a history of personality or mood disorders should avoid using THC-rich strains.

After returning home, he tried to scale the roof of his house but fell off the trash can and injured himself. Devan remembered feeling frightened by the entire incident but could not wipe a strange grin off his face. After going to the hospital, he was diagnosed with schizo-affective disorder. This condition is a combination of mood disorder and schizophrenia symptoms.

In Devan’s case, he had hallucinations of gore and zombies while the faces of strangers morphed onto those of people he knew. While in the hospital, he had the belief that one patient was an undercover officer posing as a doctor and spying on patients for the government.

Devan was placed in restraints when he tried to harm himself. Ultimately, Devan acknowledged that while the marijuana was not 100% responsible for his psychotic behavior, it without a doubt exacerbated his underlying (and possibly even dormant) condition of schizophrenia.

Finding a Definitive Answer is Tough

Many mental health specialists worldwide remain adamant that cannabis can induce psychosis. It is particularly the case among patients who already portray minor underlying symptoms and/or have experienced other “emotional abnormalities” in the past.

According to Theresa Nguyen of Mental Health America, however, these “pre-psychotic” patients find it hard to quit their marijuana use, even with the knowledge of how it may exacerbate their condition.

She bizarrely compared it to the difficulties one faces when trying to curb an addiction to junk food. Even though we realize it’s bad for us, it doesn’t necessarily make it easy to quit! She said that once patients are clean for a few days, however, the feelings of paranoia begin to fade quickly.

Nguyen also admitted that when psychosis symptoms remain after a patient has been ‘off’ cannabis for 72 hours, blame is placed solely on the brain rather than the drug. The problem, then, is determining whether or not:

  • Cannabis is an actual cause of psychosis.
  • Marijuana exacerbates existing symptoms. Alternatively, does it bring such symptoms to the fore in people likely to experience psychosis later in life even if they never touch the drug?
  • Those prone to psychosis are more likely to be attracted to marijuana.

Final Thoughts on Cannabis and Psychosis

Even anti-marijuana campaigners admit that the drug has very different effects from person to person. Moreover, users may often consume it in concert with other drugs such as alcohol and pharmaceuticals. These are drugs known to exacerbate any potential adverse effects.

It boils down to a classic argument of causation versus correlation. Marijuana use is correlated with psychosis. However, this doesn’t necessarily mean it causes it.

In cases where cannabis users are diagnosed with psychosis, how do we know which one happened first; the marijuana use or the underlying psychotic episodes? Conclusive evidence that cannabis is the cause of psychosis is practically non-existent. It is far more likely that THC exacerbates existing mental issues. This is why individuals who fit into this category should steer clear of high potency, THC-laden cannabis.

People with psychotic tendencies are potentially drawn to high-THC marijuana, which could make existing symptoms worse. If you’re in any doubt, consider using high-CBD strains only. Research suggests that it could reduce psychotic symptoms, even in individuals with schizophrenia.

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