I study
The study looked at 2,322 emergency room visits for cannabis poisoning among people aged 65 and older in Ontario. The visits took place from 2015 to 2022, allowing researchers to see what happened before and after October 2018, when Canada legalized the sale of dried cannabis, and January 2020, when the sale of edibles was legalized .
In 2015 there were 55 emergency room visits caused by cannabis poisoning. This figure increased steadily to 462 by 2021, then dropped slightly to 404 in 2022.
Dr. Stall said he was motivated to undertake the study after being called to the emergency room to consult an octogenarian who was experiencing severe confusion. The patient was barely conscious and exhibited stroke-like symptoms. Numerous tests revealed no clear cause, until Dr. Stall ordered a toxicology test and found cannabis in the patient's urine.
When Dr. Stall revealed the discovery, he said, a member of the patient's family who was present at the bedside “turned as red as a beet and realized that the elderly man had stepped into their edible cannabis product and he had mistaken it for food.”.”
Dr Stall said the patient was hospitalized and received supportive care and that there was no specific treatment or antidote for such poisonings.
Why the increase?
The study did not look at why older adults overdosed, but Dr. Stall said he and other doctors were seeing poisonings caused by accidental ingestion and intentional use of edibles for recreational or medicinal reasons.
There are several reasons why older adults might be prone to overdose, Dr. Stall said. Many strains of cannabis are much more potent than in decades past, and older adults who used the drug at an early age may underestimate the concentrations of THC they are inhaling or ingesting. Particularly with edibles, Dr. Stall said, the effect can take about three hours to kick in, which could push users to ingest too much.
Older adults also metabolize cannabis differently than younger people, Dr. Stall said, and their bodies eliminate the drug more slowly. Older adults are also more likely than younger people to take other medications, including psychoactive sleep medications, which may have problematic interactions with cannabis. And, Dr. Stall said, some older adults may already be prone to confusion or falls, which cannabis use could make worse.
“The question is, what do we do about it?” Dr. Stall said.
What can be done
Dr Stall highlighted the importance of ensuring edibles are stored indoors and in clearly identified packaging, to prevent inadvertent exposure.
Additionally, he said, policymakers should encourage specific information about cannabis dosing by older adults, along with public education campaigns about the types of conditions and circumstances that put older adults at risk when using the drug. She added that older adults who are trying cannabis for the first time may want to draw inspiration from a mantra used in geriatric medicine: “Start small and go slow.”
“This would mean starting at a lower level and going more slowly than a younger population trying cannabis for the first time,” Dr. Stall said.