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Less than half of one percent of cannabis users have ever experienced an episode of acute psychosis after getting high, according to a new study published in the Translational Psychiatry journal.
Prohibitionist groups and conservative media outlets constantly claim that smoking weed can directly lead to psychosis and other mental health issues. Clinical research studies have refuted these reefer madness myths, however, and some have suggested that psychotic disorders actually make people more likely to use cannabis, not the other way around.
Researchers from Australia, Switzerland, and the UK set out to determine the actual prevalence of “cannabis-associated psychotic symptoms” (CAPS) among everyday cannabis users. The authors specifically focused on “anxiety, panic, or psychosis-like experiences involving hallucinations or paranoia” that resulted in hospitalizations. Using Global Drug Survey data collected between 2014 and 2019, the study authors assessed lifetime rates of CAPS among 233,475 cannabis users.
Out of the nearly quarter-million cannabis users in the database, only 0.47% had ever been hospitalized with cannabis-related psychosis symptoms. And out of the very few subjects who did experience these symptoms, one-third were also using alcohol and/or other psychoactive drugs at the same time. So the percentage of people who experienced psychotic symptoms as a direct result of cannabis alone is actually smaller than half a percent.
The study makes it abundantly clear that the risk of experiencing pot-induced psychosis is exceptionally low. But for certain demographics, that risk is much higher. Subjects who had already been diagnosed with psychosis were 14 times more likely to experience CAPS. Higher rates of CAPS were also found in people who had been diagnosed with bipolar disorder, depression, or anxiety. Younger people were also 2.7 times more likely to experience psychotic reactions than older cannabis users.
Oddly, cannabis users from Denmark were three times more likely to be at risk of CAPS. The study authors theorized that this could be due to the fact that many Danish cannabis users smoke hash or resin with an average THC content of 23% or higher. In other countries, people who smoked high-potency resin were also twice as likely to be hospitalized with CAPS. These findings led researchers to conclude that high-potency cannabis increases the risk of psychotic symptoms, although other studies have come to the opposite conclusion.
Many people who were hospitalized for CAPS said they experienced these symptoms immediately after consuming high-potency products. “This finding suggests that frequency of cannabis use, over stretches of time, may be less of a risk factor for acute psychotic symptoms,” the researchers wrote. The authors theorized that most of the people who ended up in the hospital were inexperienced users who were “otherwise not used to smoking potent forms of cannabis.”
The study also reports that American cannabis users were far less likely to experience CAPS than Europeans, which suggests that legalization may play an important role in these results. During the study period, several US states legalized medical and adult-use cannabis, but weed remained strictly illegal in all of Europe. With no source of legal bud available, stoners are forced to buy black market cannabis, which is often contaminated with toxic pesticides, mold, or other toxins. This limitation makes it impossible to determine whether any of these contaminants could be contributing to the risk of psychosis.
“Our results highlight that CAPS can occur in a subset of cannabis users and that a number factors are associated with an elevated risk of CAPS (e.g., young age, mental health vulnerabilities, particularly psychosis-liability, the use of high-potency resin),” the study concludes. “Some individuals could be particularly sensitive to the adverse psychological effects of cannabis, such as young individuals or those with pre-existing mental health vulnerabilities.”
To address these concerns, the study authors recommend that government officials should make more efforts to educate young people about the potential risks of cannabis use, particularly focusing on those who are currently experiencing mental health issues.
