Cannabis use disorder is increasing rapidly, especially among older adults and people living with HIV

The new findings underscore the need for universal screening and treatment for the disorder, as well as concerted research to better understand the benefits and risks of cannabis among different populations.

Adults ages 65 and older are the fastest-growing age group to use cannabis in the United States. Cannabis use is particularly high among people living with HIV, an aging population that has reported taking this drug to manage HIV-related symptoms, side effects from antiretroviral therapy, pain, and moods.

This growing use of cannabis has contributed to an increase in cannabis use disorder (CUD) in the US over the last 20 years, according to a new study led by Boston University School of Public Health. 

Published in the Journal of Addiction Medicine, the study found that CUD diagnoses rose substantially across all age, race/ethnicity, and comorbidity subgroups nationwide from 2000 to 2022. These diagnoses were consistently higher among people living with HIV, compared to people living without HIV, and people over 65 experienced the greatest relative increase. 

These findings are concerning to health experts because older people living with HIV—and anyone with multiple health issues—may be at greater risk of experiencing adverse health effects from cannabis use, in part due to the drug’s interactions with certain medications and aging processes. Current data on CUD and how it affects different people are limited and with mixed conclusions; as the growing legalization and commercialization of cannabis across the country continues to spur an increase in use—and a decrease in perceived harms from using it—it is important to understand the drug’s potential benefits and harms among different populations.

“Older adults are an unrecognized group when it comes to cannabis use,” says study lead and corresponding author Dr. Danielle Haley, assistant professor of community health sciences at BUSPH. “We’ve devoted a lot of attention to cannabis use among youth, but clearly, older adults are also using it and experiencing harms that are severe enough to receive a clinical diagnosis of cannabis use disorder, for which there are limited treatments. As more people develop this use disorder, it's really important that we gather and disseminate information about the health effects of cannabis so that people can make informed decisions about using it.”  

At least 55 million adults use cannabis in the US, and up to 30 percent of people who use it develop CUD. Nearly 3 in 4 Americans live in a state where cannabis is legal for medical or adult use. 

For the study, Dr. Haley and colleagues examined electronic health records for 185,372 people living with and without HIV, who were receiving healthcare from the Veterans Health Administration. The researchers explored trends in cannabis use disorder by age, race/ethnicity, sex, comorbidity, and HIV status, focusing on three time periods: 2000-2015; 2016-2019; and 2020-2022. 

From 2000 to 2022, the percent of individuals with a CUD increased from 3.4 percent to 5.7 percent among people living with HIV, and from 3 percent to 4.4 percent for people living without HIV. By 2022, 20 percent of people living with HIV and 18 percent of people living without HIV had at least one CUD diagnosis, a two-fold increase of the estimated lifetime prevalence of CUD among veterans nationwide. Among people 65 and older, CUD diagnoses increased from 0.9 to 4 percent among people living with HIV, and from and 0.03 percent to 3.2 percent among those living without HIV.  

Throughout the study period, CUD prevalence was lower than other substance use disorders in the US, including alcohol use disorder, which affects nearly 29 million adults, or tobacco use disorder, which affects nearly 24 million adults. However, the wide range of cannabis products, potency, and method of use (such as vaping or ingesting through food), backed by an ever-expanding retail market, make cannabis use—and the potential for overuse—a unique challenge. Based on the current clinical understanding of cannabis, it is unclear whether CUD may occur from increased use of the drug, the adverse health effects from it, or a combination of both. There is limited  treatment for the disorder. 

“Although cannabis is regulated by states legalizing cannabis, there is an incredible amount of heterogeneity in cannabis products,” Dr. Haley says. These products can contain different amounts of tetrahydrocannabinol, or THC (the psychoactive component that creates feelings of euphoria or relaxation), compared to cannabidiol, or CBD (the nonpsychoactive chemical). Products also vary by the type of cannabis strain (such as sativa and indica) and concentration.

“These concentrations can vary substantially from product to product and people don’t always know exactly what they are purchasing,” she says, adding that it is possible that this lack of knowledge could be contributing to unintended injuries from overuse of the drug, all of which can lead to more serious consequences for older people. “If you’re an older adult and you consume a potent strain of cannabis and then trip and fall, the potential downstream effects of a fall are very different when you are 65 years old versus 20 years old.”

The adverse effects of cannabis manifest differently in different people, she says, adding to the complexities of understanding its benefits and risks. 

“Cannabis is known to be helpful with treating nausea, and has been used to manage appetite in the HIV and cancer space—but it can also contribute to hyperemesis, a condition in which people experience prolonged vomiting, even after they’ve discontinued use,” Dr. Haley says. “Similarly, many people self-medicate with cannabis to ease anxiety—but cannabis can also make anxiety worse.”

The Biden administration began first-ever efforts to recommend reclassifying cannabis as a lower-risk drug by moving it from a Schedule 1 to a Schedule 3 category. The Trump administration has not confirmed whether it will move forward with this plan, but if cannabis is rescheduled, it will likely lead to increased use, and increased CUD diagnoses.

“Our findings identify the need for universal screening and treatment for CUD as we work to understand all of the possible health effects of cannabis among different populations, especially older people and people with comorbidities,” Dr. Haley says.

The study’s senior author is Dr. Kathleen McGinnis, a researcher at the VA Connecticut Healthcare System.

** 

About Boston University School of Public Health 

Founded in 1976, Boston University School of Public Health is one of the top ten ranked schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations—especially the disadvantaged, underserved, and vulnerable—locally and globally.