Cannabis use among Americans over 65 is climbing fast, but the drug older adults encounter now bears little resemblance to what many remember from decades past. Today's marijuana is dramatically stronger, and Stanford Medicine researchers are raising urgent warnings about what that means for aging brains and hearts.
The shift in potency is stark. In the 1970s, typical marijuana contained between 1% and 4% THC, the psychoactive compound. Legal cannabis flower today averages around 20%, with some strains reaching 35%. Oils, edibles, and concentrates can approach 90% THC. The jump has outpaced medical understanding of how such concentrated doses affect older bodies.
Recent data underscores the trend. The National Survey on Drug Use and Health found that 7% of adults over 65 reported recent cannabis use in 2023, up from less than 5% in 2021. A Canadian study tracking emergency room visits after legalization found cannabis poisoning cases among seniors nearly tripled.
Eloise Theisen, a geriatric nurse practitioner specializing in cannabis therapy at Stanford Medicine, witnessed the gap firsthand. Patients in her oncology clinic were already using cannabis or considering it, often without medical guidance. "I found that our patients were going to use it whether their providers approved of it or not," she said. "Many of our patients were older, and they had risks that needed to be evaluated and addressed before they started using cannabis."
Five Health Risks Older Adults Face
Joseph Wu, director of the Stanford Cardiovascular Institute, highlighted heart disease as a primary concern. His research found that THC triggers inflammation in blood vessels. Epidemiological studies link regular cannabis use to a 29% increase in heart attacks and a 20% increase in stroke risk. While those numbers trail the dangers of heavy tobacco or alcohol use, many cannabis users combine the drug with cigarettes and alcohol, compounding cardiovascular danger.
"There is no safe amount of cannabis," Wu said. "Low doses and occasional use are still associated with vascular inflammation. Abstinence is the safest option for heart health."
Beyond the heart, older adults metabolize cannabis more slowly than younger users. The drug lingers in the body longer, extending its effects and raising the risk of dangerous interactions with prescription medications. Cannabidiol (CBD), a non-intoxicating cannabis compound, can interfere with enzymes that break down blood thinners, potentially raising drug levels and increasing bleeding risk after falls or injuries.
Cognitive issues also concern clinicians. Theisen watches for dizziness, confusion, falls, and worsening dementia symptoms in older patients using cannabis. Research on effectiveness remains murky. Smita Das, a clinical associate professor of psychiatry at Stanford Medicine, noted there is no broad medical agreement that cannabis effectively treats chronic pain, insomnia, or anxiety. The American Psychiatric Association opposes cannabis as a psychiatric treatment due to lack of evidence.
Addiction is another overlooked risk. Studies indicate roughly 30% of regular cannabis users may develop cannabis use disorder, characterized by withdrawal symptoms, escalating doses, and interference with daily life. Das pointed out that many health care providers don't routinely ask older adults about cannabis use. "This isn't a population we traditionally think about in terms of using cannabis," she said.
Some cannabis compounds have FDA approval for specific purposes. CBD is approved for certain childhood epilepsy forms, and dronabinol, a synthetic cannabis compound, treats nausea and appetite loss in cancer and HIV/AIDS patients. Research on cannabis for muscle spasms related to multiple sclerosis has shown benefits in some countries, though not the United States. But broader health claims remain unproven.
Theisen's work with palliative care patients offers a different perspective. Many face life-limiting illnesses and seek alternatives to opioid medications. Some research shows chronic pain patients using cannabis sometimes reduce opioid use. In small doses, she said, THC can provide therapeutic benefits and allow patients facing months or years to live to still experience well-being and joy.
Doctors agree on one point: open conversation matters most. Theisen has heard too many stories of patients accidentally consuming extremely high THC doses because dispensary staff provided inadequate guidance. "Your primary care physician will know the constellation of your medical conditions and other medications you might be on," said Claudia Padula, an assistant professor of psychiatry at Stanford. "Talking to your doctor will help formulate a way to do it in as safe a manner as possible."
Author Jessica Williams: "The cannabis conversation among older adults is overdue, but it demands honesty about potency and risk, not just cheerleading for access."
Comments