Cannabis-related hospital emergency visits for children and youth increased five-fold in Ontario between 2003 and 2017, according to a new study led by the CHEO Research Institute.

The study examined more than 14.5 million administrative records of emergency department visits in Ontario between 2003 and 2017. Researchers found that, not only did visits increase, but so did the medical severity of cannabis visits and the likelihood that a patient in an emergency department with cannabis intoxication would be admitted to the hospital.

The study did not explain why there was such an increase, but Bechard said there are likely a number of reasons hospitals began seeing an increase in emergency hospital visits related to cannabis as well as more related hospitalizations beginning in 2003. Among them is the higher concentration of THC, its main psychoactive compound, in cannabis now compared to decades ago, according to studies. She said it is notable that the steep increase in emergency hospital visits came during a period when student self reports indicated cannabis use was stable or even decreasing, which points to higher THC concentration not wider use.

“It’s not your grandfather’s cannabis or your father’s cannabis,” she said.

Bechard said changing societal attitudes toward cannabis also have likely played a role in the numbers of young patients presenting with serious illnesses related to cannabis at hospitals. Not only would that make people more likely to disclose their cannabis use to medical providers, but it might also mean cannabis was more easily accessible to young children in a household.

As an emergency physician at CHEO, Bechard said it has become increasingly common to have children come in after unintentionally ingesting a cannabis product.

“It is something I see day in and day out as an emergency provider.”

Ottawa-led research published last month found that cannabis poisonings in children increased dramatically after edibles were legalized in Canada in 2019 and that almost 10 per cent of all emergency department visits for poisoning in young children are now tied to cannabis.

Pediatric health providers have been trying to get public health messages out about the need for safe storage of cannabis around children.

“We want people to know legal does not mean safe and they should treat it with appropriate caution and respect.”

She said parents and family members are also encouraged to let health care providers know if they suspect cannabis is involved in a child’s illness.

Beyond unintentional ingestion, Bechard said the research indicates that it is important to educate older adolescents and teens about safer use of cannabis. Among other things, she said, health providers want them to use lower doses, to increase usage slowly and to be careful not to ingest large amounts in edibles.

Bechard said people are often surprised to learn you can overdose on cannabis. It is also important for emergency department clinicians to “maintain a high index of suspicion” for cannabis exposure in young people coming to the emergency department, she said.

“We know this phenomenon is happening and will likely become more severe.”