Legalized weed is landing more seniors in the ER

As more places legalize marijuana, policymakers and health officials have worried about the health risks that the drug may pose to adolescents. But a new study suggests that an additional demographic is at risk: seniors.

The study, published last month in JAMA Internal Medicine, found that after Canada legalized marijuana, the number of emergency room visits for cannabis poisoning rose sharply among people 65 and older. Poisonings doubled after Canada legalized sale of the cannabis flower and then tripled just 15 months later, when Canada legalized the sale of edibles.

“It’s often a baked good, a chocolate or a gummy,” said Dr. Nathan Stall, a geriatrician at Mount Sinai Hospital and researcher at Women’s College Hospital in Toronto, and lead author on the study. Stall noted that researchers and emergency room doctors were finding that seniors used drugs intentionally but also sometimes by accident, when edibles were mistaken for regular food or snacks.

Symptoms of cannabis poisoning can include dizziness, confusion, nausea, loss of coordination and balance, drowsiness and hallucinations.

The findings were consistent with other research published in the United States, Stall said, and showed that more attention needed to be paid to drug use by seniors and to the health effects.

“It’s somewhat in the shadows, and there is some ageism and bias in thinking that older adults aren’t using drugs,” Stall said.

The study looked at 2,322 emergency room visits for cannabis poisoning among people 65 and older in Ontario. The visits spanned 2015 through 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. That figure rose steadily to 462 by 2021 and then fell off slightly to 404 in 2022.

Stall said he was motivated to undertake the study after being called into the emergency room to consult on an octogenarian who was experiencing severe confusion. The patient was barely conscious and showed strokelike symptoms. Multiple tests revealed no clear cause, until Stall ordered a toxicology test and found cannabis in the patient’s urine.

When Stall disclosed the finding, he said, a family member of the patient who was present at the bedside “went beet red and realized that the older adult had got into their edible cannabis product and mistaken it for food.”

Stall said that the patient was hospitalized and given supportive care, and that there was not a specific treatment or antidote for such poisonings.

The study did not look at why seniors overdosed, but Stall said that he and other doctors were seeing poisonings caused by accidental ingestion as well as intentional use of edibles for recreation or medicinal reasons.

There are several reasons seniors might be prone to overdose, Stall said. Many cannabis strains are far more potent than in past decades, and seniors who used the drug earlier in life may underestimate the concentrations of THC they are inhaling or ingesting. Particularly with edibles, Stall said, the high can take about three hours to unfold, which might prompt users to ingest too much in the buildup.

Older adults also metabolize cannabis differently from younger people, Stall said, and their bodies eliminate the drug more slowly. Seniors also are more likely than younger people to take other medications, including psychoactive drugs for sleep, that can have problematic interactions with cannabis. And, Stall said, some seniors might already be prone to confusion or falling, which the use of cannabis could worsen.

“The question is: ‘What do we do about it?’” Stall said.

Stall noted the importance of ensuring edibles were kept in locked locations and in clearly identified packaging to prevent unintentional exposure.

Also, he said, policymakers should encourage senior-specific dosing information for cannabis, along with public-education campaigns about the kinds of conditions and circumstances that put older adults at risk when using the drug. He added that seniors who are experimenting with cannabis for the first time might want to draw from a mantra used in geriatric medicine: “Start low and go slow.”

“That would mean starting lower and going slower than a younger population who is trying cannabis for a first time,” Stall said.