One of the many arguments in favor of the decriminalization of marijuana is that it is nearly impossible to die from an overdose from smoking pot. Edible forms of THC, the main psychoactive ingredient in marijuana, have unfortunately made it possible to die from an overdose of ingesting THC. According to Drug Policy Facts:

Despite the widespread illicit use of cannabis there are very few if any instances of people dying from an overdose.

Marijuana is not harmless, however. The increased potency of marijuana and the variety of ways it is consumed, including smoking, eating, vaping, and dapping, is leading to a surge in reported cases of cannabis-induced psychosis.

A 2019 article in the International Journal of Environmental Research and Public Health examines the relationship between cannabis and psychosis through the criteria laid out in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). According to the authors:

Cannabis intoxication becomes Cannabis-Induced Psychotic Disorder once certain severity and duration criteria are met and Cannabis-Induced Psychotic Disorder is heavily associated with future schizophrenia diagnoses.

What are the psychotic symptoms displayed with cannabis-induced psychosis? They must include hallucinations or delusions. Therefore, it presents itself similarly to schizophrenia. The hallucinations or delusions must not precede the cannabis use and must be observed, either while intoxicated or coming down from intoxication, to qualify as cannabis-induced psychosis. Other symptoms include:

• deficits in attention
• weak working memory
• problems with verbal and executive function
• deficits in motor and speech areas of the brain
• disorganized speech
• catatonic behavior

If the psychosis persists beyond the period of withdrawal from intoxication, the diagnosis of cannabis-induced psychosis may be faulty. If problems persist for longer than a month, other causes should be explored. It is difficult to identify cannabis-induced psychosis if other drugs are being used simultaneously.

The exact numbers of people who experience cannabis-induced psychosis are not readily available. One decade-long study from Denmark noted that:

The incidence rate of cannabis-induced psychosis increased steadily from 2.8 per 100,000 person years in 2006 to 6.1 per 100,000 person years in 2016.

By comparison, the rate of death by drug overdose in the United States is about 30 per 100,000. A study of 230,000 marijuana users found that less than half of one percent reported “hallucinations or paranoia requiring emergency medical treatment.” The authors focused on the use of high-potency marijuana and especially resins:

[T]he [psychotic] event was characterized by the use of predominantly high-potency forms of cannabis, and mostly not due to the co-use of other substances.

A major question regarding cannabis-induced psychosis is whether the likelihood of becoming schizophrenic precedes cannabis use or whether cannabis use can trigger schizophrenia. An attempt at finding a gene associated with cannabis-induced psychosis has been somewhat successful, but there is no genetic therapy on the horizon.

Written by Steve O’Keefe. First published May 14, 2024.

Sources:

“Marijuana Facts,” Drug Policy Facts, retrieved May 13, 2024.

“Virginia mother pleads guilty in 4-year-old son’s death from THC gummies,” NBC4 Washington, June 12, 2023.

“Cannabis and Psychosis Through the Lens of DSM-5,” International Journal of Environmental Research and Public Health, October 2019.

“Cannabis-Induced Psychotic Disorder and Schizophrenia Diagnostic Comparison,” by Tyanna Brodhagen, Western Michigan University Honors Thesis, December 13, 2023.

“Annual incidence of cannabis-induced psychosis, other substance-induced psychoses and dually diagnosed schizophrenia and cannabis use disorder in Denmark from 1994 to 2016,” Psychological Medicine, December 2019.

“Rates and correlates of cannabis-associated psychotic symptoms in over 230,000 people who use cannabis,” Translational Psychiatry, September 2022.

“Cannabis induced psychosis: A systematic review on the role of genetic polymorphisms,” Pharmacological Research, July 2022.

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