Stanford Medicine Experts Warn of Potent Cannabis and Emerging Health Risks for Older Americans

As cannabis use continues its upward trajectory across the United States, particularly among the senior population, experts at Stanford Medicine are sounding an urgent alarm: contemporary marijuana products are significantly more potent than many individuals realize, carrying a spectrum of substantial health risks that warrant careful consideration. This growing trend, coupled with the evolving landscape of cannabis potency, necessitates a deeper understanding among older adults about the potential consequences of consumption.

The Shifting Landscape of Cannabis Potency

For decades, cannabis has been perceived by many as a relatively benign substance, often associated with a milder potency from the 1970s and 80s. However, scientific advancements in cultivation and extraction techniques have dramatically altered this reality. Eloise Theisen, a geriatric nurse practitioner specializing in cannabis therapy at Stanford Medicine, encountered this firsthand. Her own journey with cannabis began after a severe car accident left her with chronic pain that eluded conventional treatments. Upon returning to her work in an oncology clinic, she observed a prevalent, often unsupervised, use of cannabis among her patients. "I found that our patients were going to use it whether their providers approved of it or not," Theisen stated. "Many of our patients were older, and they had risks that needed to be evaluated and addressed before they started using cannabis." This observation underscored a critical gap in patient education and professional guidance.

The potency of cannabis is primarily attributed to tetrahydrocannabinol (THC), the psychoactive compound responsible for the "high" associated with marijuana. In the 1970s, the average THC content in cannabis flower hovered between a modest 1% and 4%. Today, legal cannabis flower commonly averages around 20% THC, with some strains reaching as high as 35%. The escalation in potency is even more pronounced in concentrated forms. Oils, edibles, and other extracts can contain THC levels approaching a staggering 90%. This dramatic increase in psychoactive ingredient concentration presents a significant challenge for understanding its impact on the brain and body, as highlighted by Dr. Claudia Padula, an assistant professor of psychiatry and behavioral sciences at Stanford Medicine. "We’re trying to catch up in our understanding of how that drastic of an increase in the psychoactive ingredient is impacting the brain and the body," Dr. Padula noted.

Rising Use Amidst Research Gaps

The rise in cannabis use among older adults is a demographic trend that medical professionals are increasingly observing. Both medical and recreational cannabis are now legal in numerous states, contributing to broader societal acceptance and accessibility. According to the National Survey on Drug Use and Health, the percentage of adults over 65 reporting recent cannabis use climbed to 7% in 2023, a notable increase from less than 5% in 2021. This growing segment of the population often turns to cannabis with the hope of alleviating common ailments such as chronic pain, insomnia, and anxiety.

However, a significant hurdle remains: a lack of broad medical consensus on the efficacy of cannabis for these conditions. Dr. Smita Das, a clinical associate professor of psychiatry and behavioral sciences at Stanford Medicine, emphasizes this point. "There is still no broad medical agreement that cannabis effectively treats these conditions," she stated. This uncertainty is partly due to the federal illegality of marijuana, which complicates and restricts comprehensive scientific research into its therapeutic and adverse effects.

Unique Risks for Older Adults

Older adults are not simply a larger demographic of cannabis users; they face a distinct set of risks due to physiological changes associated with aging. These risks include a heightened susceptibility to cardiovascular issues, certain cancers, addiction, cognitive impairment, and dangerous interactions with prescription medications. The increased potency of modern cannabis products further exacerbates these concerns, leading to a greater risk of accidental overuse. A Canadian study examining emergency room visits before and after national cannabis legalization revealed a nearly threefold increase in cannabis poisoning cases among adults over 65, underscoring the impact of higher THC levels and varied product formulations. "There are so many different formulations and so many different strengths," Dr. Das observed. "This is really not the cannabis of the ’70s."

Cardiovascular Concerns and Cognitive Impact

Research, though still developing, has begun to establish links between regular cannabis use and cardiovascular disease. Dr. Joseph Wu, director of the Stanford Cardiovascular Institute and a professor of medicine and radiology, finds this particularly alarming given that heart disease remains the leading cause of death in the United States. His research team’s animal studies have shown that THC can trigger inflammation in blood vessels. Epidemiological research in humans has also correlated cannabis use with an increased risk of heart attacks (a 29% increase) and strokes (a 20% increase). While these risks may be lower than those associated with heavy tobacco or alcohol consumption, the co-occurrence of cannabis use with these other substances can amplify cardiovascular dangers. Furthermore, smoking cannabis has been associated with lung cancer and cancers of the head and neck. Dr. Wu points out that smoking and vaping cannabis appear to induce more inflammation than edible forms, although edibles are not without their own risks. "There is no safe amount of cannabis. Low doses and occasional use are still associated with vascular inflammation," he cautioned. "Abstinence is the safest option for heart health."

Beyond cardiovascular health, Theisen frequently observes other complications in older patients using cannabis, including dizziness, confusion, falls, and the exacerbation of cognitive issues like dementia. The aging body metabolizes cannabis more slowly, meaning the drug can persist in the system longer, leading to prolonged and potentially unexpected effects. This slower metabolism also elevates the risk of adverse interactions with existing medications. A notable example involves cannabidiol (CBD), a non-intoxicating cannabis compound. CBD can interfere with enzymes crucial for metabolizing medications, such as blood thinners. This interference can lead to elevated drug levels in the body, increasing the danger of bleeding following an injury or fall. In some instances, cannabis use might also diminish the effectiveness of essential medications.

The Reality of Cannabis Addiction

A persistent misconception is that cannabis is not addictive. However, Dr. Das refutes this notion, citing research that indicates approximately 30% of regular cannabis users may develop cannabis use disorder. This condition, akin to other substance use disorders, is diagnosed based on the drug’s impact on an individual’s daily life, manifesting as withdrawal symptoms, a need for increased doses over time, or interference with personal relationships and responsibilities. While cannabis addiction rates are generally lower than those for alcohol, Dr. Das notes that healthcare providers often do not routinely inquire about cannabis use among older adults, contributing to underdiagnosis and a lack of support. "I’m noticing that older adults may not necessarily be disclosing cannabis use to their providers unless specifically asked. This isn’t a population we traditionally think about in terms of using cannabis," she explained. "If someone comes to me for another reason such as depression or alcohol use disorder, I might be the first person who has asked them about their cannabis use." For those seeking to reduce or cease their use, open communication with a physician or addiction specialist is paramount. Evidence-based treatments, such as cognitive behavioral therapy, have shown promise in aiding recovery. "Empowering individuals by helping them understand the criteria of a substance use disorder can then help them decide, ‘Is this something I want to talk about?’" Dr. Das elaborated. "On the clinician side, we can do a lot to make substance use part of the conversation. What are they using the cannabis for? And if somebody wants to stop using, we need to stick with them through the difficult part of stopping." Dr. Padula’s research, employing functional MRI scans, is exploring how the brain reacts to environmental cues in individuals with cannabis use disorder, revealing heightened sensitivity to drug-related signals in those who relapse after treatment.

Potential Benefits and the Need for Evidence

While the risks are significant, it is important to acknowledge that cannabis may offer therapeutic benefits for certain conditions, though research in these areas remains limited. Studies suggest that different age groups utilize cannabis for diverse reasons. A 2017 study led by Dr. Padula found that younger adults (18-30) were more likely to use cannabis for boredom or social engagement. Middle-aged users commonly reported insomnia, while adults aged 51-72 frequently used it for cancer, chronic pain, or other long-term medical conditions.

It is crucial to distinguish between cannabis itself and FDA-approved cannabis-related compounds. The Food and Drug Administration (FDA) has not approved cannabis as a medical treatment. However, it has approved two cannabis-derived compounds: CBD for specific forms of childhood epilepsy and dronabinol (a synthetic cannabis compound) for managing nausea and appetite loss in patients undergoing cancer treatment or living with HIV/AIDS. Cannabis compounds have also demonstrated benefits for muscle spasms associated with multiple sclerosis, leading to approval for this purpose in some countries, though not yet in the United States.

CBD products are widely marketed for a range of conditions including pain, sleep disturbances, anxiety, and substance use disorders. However, robust scientific evidence to support many of these claims is still lacking. Research into cannabis for chronic pain has yielded mixed results, with some studies reporting pain relief while others note significant placebo effects. The American Psychiatric Association, with input from Dr. Das, has issued a statement opposing cannabis as a psychiatric treatment due to the absence of evidence demonstrating its effectiveness for psychiatric disorders.

Conversely, Theisen’s work with palliative care patients facing life-limiting illnesses offers a different perspective. Many of these patients utilize cannabis to manage cancer-related symptoms, particularly pain, and often seek alternatives to opioid medications, which carry risks of serious side effects and addiction. Research indicates that chronic pain patients using cannabis sometimes reduce their opioid consumption. Theisen also observes that many patients find cannabis enhances their sense of well-being. "THC has gotten a bad rap over the years, but in very small doses it can be therapeutic," she commented. "There’s also a lot of stigma around its effects of euphoria. In our patients who may have months to a few years to live, still being able to experience joy is really important."

The Imperative of Open Dialogue with Healthcare Providers

Despite ongoing debates about the precise medical utility of cannabis, Stanford Medicine experts universally agree on one critical point: older adults must engage in open and honest conversations with their healthcare providers before using cannabis. Theisen advocates for patients to seek guidance from medical professionals rather than relying on advice from dispensary staff or self-experimentation. She recounts numerous instances from the early years of legalization where patients, lacking proper instructions, inadvertently consumed extremely high doses of THC edibles, leading to emergency room visits or a negative perception of cannabis. "Patients would sometimes end up in the emergency department, or they would not want to take it again because they thought, ‘This isn’t going to work for me,’" she said.

Reliable, unbiased information about cannabis remains challenging to access. Healthcare providers can assist patients in evaluating the appropriateness of cannabis, discussing potential alternatives, and identifying specific risks related to their existing medical conditions and current medications. "Your primary care physician will know the constellation of your medical conditions and other medications you might be on," Dr. Padula emphasized. "Talking to your doctor and letting them know not only what you’re prescribed, but what you’re using recreationally, will help formulate a way to do it in as safe a manner as possible." This proactive approach ensures that decisions regarding cannabis use are informed, personalized, and prioritize the overall health and safety of older adults.