Claim that there are “no deaths from cannabis use anywhere” is misleading

A social media post by the Facebook page Eco Groovy, which has more than 14,000 followers, claimed that “There are no deaths from cannabis use anywhere”. This claim took the form of a meme and was attributed to the late Lester Grinspoon, who was an associate professor of psychiatry at Harvard University. Grinspoon was an advocate of drug policy reform, especially that which related to cannabis.

Cannabis (also known as marijuana or weed) is derived from the plant Cannabis sativa. It contains the chemical compound tetrahydrocannabinol (THC), which is primarily responsible for the drug’s mind-altering effects. Many use the drug recreationally to feel happy and relaxed, although others report experiencing negative effects like anxiety and paranoia. Some studies have found associations between chronic cannabis use and mental illness^[1], although further research is still needed to understand the nature of these associations.

Cannabis is commonly used by smoking, although it can also be inhaled by using oils containing cannabis extracts or ingested through edibles.

Science Feedback examined similar claims downplaying the potential risks of cannabis use in previous reviews (see here and here).

We sought to verify the origin of the quote. Grinspoon published several books on cannabis, such as “Marihuana Reconsidered”, but a search of the quote on Google produced results that, like the post, published the quote and attributed it to Grinspoon (see examples here, here, and here), but didn’t indicate where or when Grinspoon allegedly made the statement.

We also checked the book cataloging website Goodreads, which documents quotes in books. Despite the quote’s popularity among cannabis-promoting websites, we didn’t find it listed under Grinspoon’s entry on Goodreads. Overall, this suggests that Grinspoon didn’t actually make that statement, and that the attribution to him is possibly inaccurate. This phenomenon of misquotes, frequently of evocative statements like the one attributed to Grinspoon, is fairly common.

Apart from the potentially inaccurate attribution, the claim is also misleading.

It’s true that unlike other drugs of abuse like opioids—the leading cause of overdose deaths in the U.S. and involved in more than 70% of overdose deaths in 2022 in Europe—achieving a lethal overdose of cannabis is relatively more difficult, though not impossible. That said, the findings of some studies suggest that deaths following cannabis use are mainly due to the effects of cannabis interacting with other factors, rather than to cannabis alone.

For example, this study in England, which examined deaths between 1998 and 2011 where cannabinoids were detected in the deceased, reported that out of 3455 deaths analyzed, 136 or 4% occurred after cannabis use alone^[2]. Thus, the researchers concluded that “​​[d]eath following use of cannabis alone was rare”.

55% of these deaths were due to self-inflicted injuries, such as hanging and traumatic injury following a fall, and 41% were due to traffic accidents. Just 14 cases listed cannabis use as the underlying cause of death on the death certificate: nine of the 14 deaths were due to heart failure. Just one was solely attributed to cannabis toxicity.

Another study in Florida examined more than 380 deaths in the state associated with cannabinoids and synthetic cannabinoids. It reported that more than 90% of these deaths were from accidents, mainly as a result of drug intoxication and road traffic collisions^[3].

These findings are consistent with the reported effects of cannabis on the brain. Some studies have found that cannabis is detrimental to a person’s reaction time, ability to assess distance, and coordination^[1]. The U.S. Centers for Disease Control and Prevention (CDC) states that “[a]fter alcohol, cannabis is the substance most often associated with impaired driving”.

Smoking cannabis has also been associated with an increased risk for stroke and heart disease, although determining how much of this effect is due to cannabis itself and how much is due to harmful compounds in smoke is challenging.

Finally, cannabis edibles, which have become widely available, have different risks compared to smoked cannabis. Children are at particular risk due to their lower body weight compared to adults. Acute cannabis poisoning in children can and has led to potentially serious consequences, such as difficulty breathing and coma.

A study by researchers in Illinois found more than 7,000 pediatric exposures to cannabis recorded in the National Poison Data System between 2017 and 2021^[4]. Approximately 22% of these cases were admitted to the hospital; about 8% were admitted to critical care units and a few cases required ventilation.

The study reported that no deaths occurred in the period studied. But it’s plausible to infer that had some of these critical cases not received timely medical attention, death might have been the result.

The American College of Medical Toxicology released a position statement in 2019 addressing pediatric exposure to cannabis. It stated that “inadvertent cannabis exposures in children have been on the rise, leading to significant adverse events” and that “[t]here is no specific antidote for cannabis poisoning, and care is largely supportive”. It called for measures to reduce the risk of pediatric cannabis poisoning, such as improved labeling of cannabis edibles to include warnings and ensuring that edibles aren’t stored within the reach of children.

In summary, the claim that cannabis use hasn’t resulted in any deaths anywhere is misleading. While deaths directly caused by cannabis toxicity are relatively uncommon compared to other drugs of abuse like opioids, cannabis can indirectly contribute to death as a result of its detrimental effects on motor function and coordination, increasing the risk of events like falls and road traffic accidents.

REFERENCES

• 1 – Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. (2017) Available from: https://www.ncbi.nlm.nih.gov/books/NBK425742/
• 2 – Rock et al. (2022) Can cannabis kill? Characteristics of deaths following cannabis use in England (1998–2020). Journal of Psychopharmacology.
• 3 – Suriaga et al. (2022) Cannabinoids and synthetic cannabinoids as a cause of death: Trends and their healthcare implications. Journal of Nursing Scholarship.
• 4 – Tweet et al. (2023) Pediatric Edible Cannabis Exposures and Acute Toxicity: 2017–2021. Pediatrics.