By Paula Span, KFF Health News

Benjamin Han, a geriatrician and addiction medicine specialist at the University of California, San Diego, tells his students a cautionary tale about a 76-year-old patient who, like many older people, struggled with insomnia.

“She had problems falling asleep, and she’d wake up in the middle of the night,” he said. “So her daughter brought her some sleep gummies” — edible cannabis candies.

“She tried a gummy after dinner and waited half an hour,” Han said.

Feeling no effects, she took another gummy, then one more — a total of four over several hours.

Han advises patients who are trying cannabis to “start low; go slow,” beginning with products that contain just 1 or 2.5 milligrams of tetrahydrocannabinol, or THC, the psychoactive ingredient that many cannabis products contain. Each of the four gummies this patient took, however, contained 10 milligrams.

The woman started experiencing intense anxiety and heart palpitations. A young person might have shrugged off such symptoms, but this patient had high blood pressure and atrial fibrillation, a heart arrhythmia. Frightened, she went to an emergency room.

Lab tests and a cardiac work-up determined the woman wasn’t having a heart attack, and the staff sent her home. Her only lingering symptom was embarrassment, Han said. But what if she’d grown dizzy or lightheaded and was hurt in a fall? He said he has had patients injured in falls or while driving after using cannabis. What if the cannabis had interacted with the prescription drugs she took?

“As a geriatrician, it gives me pause,” Han said. “Our brains are more sensitive to psychoactive substances as we age.”

Thirty-nine states and the District of Columbia now allow cannabis use for medical reasons, and in 24 of those states, as well as the district, recreational use is also legal. As older adults’ use climbs, “the benefits are still unclear,” Han said. “But we’re seeing more evidence of potential harms.”

A wave of recent research points to reasons for concern for older users, with cannabis-related emergency room visits and hospitalizations rising, and a Canadian study finding an association between such acute care and subsequent dementia. Older people are more apt than younger ones to try cannabis for therapeutic reasons: to relieve chronic pain, insomnia, or mental health issues, though evidence of its effectiveness in addressing those conditions remains thin, experts said.

In an analysis of national survey data published June 2 in the medical journal JAMA, Han and his colleagues reported that “current” cannabis use (defined as use within the previous month) had jumped among adults age 65 or older to 7% of respondents in 2023, from 4.8% in 2021. In 2005, he pointed out, fewer than 1% of older adults reported using cannabis in the previous year.

What’s driving the increase? Experts cite the steady march of state legalization — use by older people is highest in those states — while surveys show that the perceived risk of cannabis use has declined. One national survey found that a growing proportion of American adults — 44% in 2021 — erroneously thought it safer to smoke cannabis daily than cigarettes. The authors of the study, in JAMA Network Open, noted that “these views do not reflect the existing science on cannabis and tobacco smoke.”

The cannabis industry also markets its products to older adults. The Trulieve chain gives a 10% discount, both in stores and online, to those it calls “wisdom” customers, 55 or older. Rise Dispensaries ran a yearlong cannabis education and empowerment program for two senior centers in Paterson, New Jersey, including field trips to its dispensary.

The industry has many satisfied older customers. Liz Logan, 67, a freelance writer in Bronxville, New York, had grappled with sleep problems and anxiety for years, but the conditions grew particularly debilitating two years ago, as her husband was dying of Parkinson’s disease. “I’d frequently be awake until 5 or 6 in the morning,” she said. “It makes you crazy.”

Looking online for edible cannabis products, Logan found that gummies containing cannabidiol, known as CBD, alone didn’t help, but those with 10 milligrams of THC did the trick without noticeable side effects. “I don’t worry about sleep anymore,” she said. “I’ve solved a lifelong problem.”

But studies in the United States and Canada, which legalized nonmedical cannabis use for adults nationally in 2018, show climbing rates of cannabis-related health care use among older people, both in outpatient settings and in hospitals.

In California, for instance, cannabis-related emergency room visits by those 65 or older rose, to 395 per 100,000 visits in 2019 from about 21 in 2005. In Ontario, acute care (meaning emergency visits or hospital admissions) resulting from cannabis use increased fivefold in middle-aged adults from 2008 to 2021, and more than 26 times among those 65 and up.

“It’s not reflective of everyone who’s using cannabis,” cautioned Daniel Myran, an investigator at the Bruyère Health Research Institute in Ottawa and lead author of the Ontario study. “It’s capturing people with more severe patterns.”

But since other studies have shown increased cardiac risk among some cannabis users with heart disease or diabetes, “there’s a number of warning signals,” he said.

For example, a disturbing proportion of older veterans who currently use cannabis screen positive for cannabis use disorder, a recent JAMA Network Open study found.

As with other substance use disorders, such patients “can tolerate high amounts,” said the lead author, Vira Pravosud, a cannabis researcher at the Northern California Institute for Research and Education. “They continue using even if it interferes with their social or work or family obligations” and may experience withdrawal if they stop.

Among 4,500 older veterans (with an average age of 73) seeking care at Department of Veterans Affairs health facilities, researchers found that more than 10% had reported cannabis use within the previous 30 days. Of those, 36% fit the criteria for mild, moderate, or severe cannabis use disorder, as established in the Diagnostic and Statistical Manual of Mental Disorders.

VA patients differ from the general population, Pravosud noted. They are much more likely to report substance misuse and have “higher rates of chronic diseases and disabilities, and mental health conditions like PTSD” that could lead to self-medication, she said.

Current VA policies don’t require clinicians to ask patients about cannabis use. Pravosud thinks that they should.

Moreover, “there’s increasing evidence of a potential effect on memory and cognition,” said Myran, citing his team’s study of Ontario patients with cannabis-related conditions going to emergency departments or being admitted to hospitals.

Compared with others of the same age and sex who were seeking care for other reasons, research shows these patients (ages 45 to 105) had 1.5 times the risk of a dementia diagnosis within five years, and 3.9 times the risk of that for the general population.

Even after adjusting for chronic health conditions and sociodemographic factors, those seeking acute care resulting from cannabis use had a 23% higher dementia risk than patients with noncannabis-related ailments, and a 72% higher risk than the general population.

None of these studies were randomized clinical trials, the researchers pointed out; they were observational and could not ascertain causality. Some cannabis research doesn’t specify whether users are smoking, vaping, ingesting or rubbing topical cannabis on aching joints; other studies lack relevant demographic information.

“It’s very frustrating that we’re not able to provide more individual guidance on safer modes of consumption, and on amounts of use that seem lower-risk,” Myran said. “It just highlights that the rapid expansion of regular cannabis use in North America is outpacing our knowledge.”

Still, given the health vulnerabilities of older people, and the far greater potency of current cannabis products compared with the weed of their youth, he and other researchers urge caution.

“If you view cannabis as a medicine, you should be open to the idea that there are groups who probably shouldn’t use it and that there are potential adverse effects from it,” he said. “Because that is true of all medicines.”

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