On Wednesday, Steve wrote about the lack of high quality evidence in support of medicinal marijuana for most of the myriad conditions for which people claim benefit. In his post, he touched briefly on the issue of safety when he included the following quote from a 2018 systematic review on the use of cannabinoids for multiple sclerosis:

However, cannabis use has been associated with an increased risk of psychosis and schizophrenia in at-risk individuals, there is growing evidence that cannabis can increase the risk for cardiovascular diseases, including myocardial infarction (MI), hypertension, heart failure, and stroke, and a recently recognized adverse effect of cannabis is cannabinoid hyperemesis syndrome.

Coincidentally I was also planning on writing a post about the subject, although from the angle of safety concerns in young children, specifically the risk of harm from accidental ingestion. Before I get to that, I would like to point out that some of the issues listed in the above quote do effect pediatric patients. I have personally taken care of one teenager who have developed psychosis believed to be attributed to heavy marijuana use, and several older children who had developed debilitating chronic nausea.

Canadian cannabis chocolate sends a toddler to the hospital

What got my attention this week was an article written by this Yvette d’Entremont (not that Yvette d’Entremont) in The Star Halifax about a local 4-year-old child that had been hospitalized after eating 15 pieces of a chocolate bar containing cannabis. One piece would have been the typical daily dose for an adult, and 15 is a lot more than that, even using the metric system. The article doesn’t go into the details of her clinical presentation, but I assume it was severe if it warranted admission. Thankfully she recovered and was discharged home in good health.

On October 17th, marijuana possession will become legal in Canada, although the selling of edibles will remain illegal. It’s easy to imagine that marijuana in all its various forms will soon become more widely prevalent, just like it has in the states that have legalized medicinal, and especially recreational, marijuana. Increasing prevalence of edibles, particularly those that come in candy, cookie, brownie, or chocolate varieties, means that more children will live in homes and ride in cars as in the Halifax case, where marijuana is present. And this means that more children will suffer toxic effects from unintentional ingestion.

I assume you have evidence to justify your concerns, Dr. Jones

Yes, yes I do.

Probably the best place to look into this potential outcome is in Colorado, the first state to legalize recreational marijuana. A 2016 JAMA Pediatrics paper did just that. In fact, this was the first paper to specifically look at the effect of recreational marijuana in the pediatric population.

This retrospective cohort study involved inpatient and outpatient visits to Children’s Hospital Colorado, Aurora and its associated urgent care centers as well as Colorado regional poison control cases from January 1, 2009 to December 31, 2015. The study focused on children under the age of 9 years and found that hospital visits related to marijuana exposure were twice as frequent 2 years after legalization compared to 2 years prior, and that edibles were to blame for half of them.

In addition to this, poison control cases were 5 times more frequent in 2015 compared to 2009, an increase of 34% each year. The rest of the country only saw a 19% increase. Edibles also accounted for half of these calls, and poor child supervision or inappropriate product storage were common factors. The authors concluded that legalization of recreational marijuana played a role in the significant increase in pediatric ingestions.

Vous avez surement plus de preuves que ca!

Oui, oui je fais.

Cannabis is illegal in France, but it is an extremely popular recreational drug, particularly among teenagers and young adults. The most popular form of marijuana used in France is hashish, a resin that is either smoked or eaten. There has been a trend of increasing use and increasing THC concentrations in marijuana over several years, which raised concerns of pediatric exposure risk.

In September of last year, French researchers published a report in Pediatrics that looked at admissions for pediatric unintentional cannabis intoxication over an eleven year period ending in 2014. This retrospective, national, multicenter, observational pediatric cohort study involved all children under the age of 6 years admitted to a pediatric emergency department for symptoms proven via toxicological testing to be caused by cannabis ingestion. They found some alarming trends.

During the study period, annual admissions increased by a factor of 13, and as would be expected hashish resin was to blame in about 3 out of every 4 cases. In addition to the significant increase in proven toxicity from cannabis in children, they found that the age at admission was also trending younger and that the clinical presentations were more severe, in particular the incidence of coma was substantially higher. Cannabis-related admissions outpaced all other ingestions in this age group.

The study authors rudely point out that these factors are also an issue in the United States, and are more concerning where marijuana has been decriminalized. Furthermore, they add, attractive packaging and names that mimic actual food products, such as “Pot Tarts” and “Munchy Way”, that are increasingly popular in the United States, likely increase the risk of unintentional ingestion. In countries where THC concentrations have remained low, or where use primarily consists of smoking in coffee shops, pediatric unintentional ingestions are almost unheard of.

One more study for good measure

In November of 2017, The Journal of Pediatrics published a systematic review of published reports of unintentional cannabis ingestions in children, specifically children under the age of 13 years. Unsurprisingly, they found a bunch of them. Here are a few take home tidbits from this paper:

  1. Children with cannabis toxicity more commonly present with lethargy, difficulty walking, poor muscle tone, fast heart rates, and low respiratory rates.
  2. Young children explore their environment with their mouths, so ingestions most likely result from discovery of cannabis-infused food items left unsecured by an adult.
  3. Older children like to eat things that look and/or taste good, and many edibles come in the form of cookies, candies, and cakes in attractive and familiar packaging.
  4. Commercial edibles can contain extremely high doses of THC and are meant for consumption over time, but kids like to eat the whole damn thing.
  5. Hashish is often mistaken for chocolate by young children.
  6. Unintentional pediatric ingestions have increased in states where marijuana has been legalized, particularly recreational use, and this is expected to continue.
  7. In these states, the perception of toxicity risk is lower compared to states where marijuana is not legal.
  8. Acute and chronic marijuana use by adults can impair cognitive and executive function, attention, and memory, which might increase the risk of improper storage.
  9. There are no federal regulations on the packaging of cannabis products, as there are with all other toxic household products, OTC medications, and prescription medications.
  10. This is going to get worse before it gets better.

Conclusion: Pediatric ingestions are inevitable but we can reduce the risk

It’s hard to argue with the claim that as more marijuana is around children, and particularly more edibles that look and taste like candy, there will be more unintentional ingestions of it. Eating stuff that they shouldn’t is just a thing that young children do. Unfortunately, there is reason to worry that partaking caregivers, older siblings, and visitors to the home are not going to be as diligent about keeping pot and pot products out of reach of children as they might bleach or rat poison.

Marijuana obviously isn’t going anywhere, and I personally don’t think that the issue of pediatric ingestion should be used as an unwieldy cudgel in someone’s fight against legalization. As is often the case, education and regulation is the key. This means recognition of this potential problem by healthcare professionals and frank discussions with families. Public health campaigns need to be implemented. In addition, our elected leaders need to step up and enact laws that will help to protect children.

Ingestions are going to happen, but you can reduce the risk. In fact, you can start right now by putting that stuff out of the reach of children. Finally, if you are seeking medical attention for a child that may have ingested marijuana, even if you weren’t exactly obeying your particular state’s laws regarding marijuana possession and use, please be honest with the medical professional caring for them.


Posted by Clay Jones

Clay Jones, M.D. is a pediatrician and a regular contributor to the Science-Based Medicine blog. He primarily cares for healthy newborns and hospitalized children, and devotes his full time to educating pediatric residents and medical students. Dr. Jones first became aware of and interested in the incursion of pseudoscience into his chosen profession while completing his pediatric residency at Vanderbilt Children’s Hospital a decade ago. He has since focused his efforts on teaching the application of critical thinking and scientific skepticism to the practice of pediatric medicine. Dr. Jones has no conflicts of interest to disclose and no ties to the pharmaceutical industry. He can be found on Twitter as @SBMPediatrics and is the co-host of The Prism Podcast with fellow SBM contributor Grant Ritchey. The comments expressed by Dr. Jones are his own and do not represent the views or opinions of Newton-Wellesley Hospital or its administration.