HOLY SMOKE

Health risks from cannabis may grow as users age

- PAULA SPAN

Dr 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 another — 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 2.5mg of tetrahydrocannabinol, or THC, the psychoactive ingredient that many cannabis products contain. Each of the four gummies this patient took, however, contained 10mg.

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

Lab tests and a cardiac workup determined that 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 Washington, DC, now allow cannabis use for medical reasons, and in 24 of those states, as well as Washington, 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."