Medical cannabis use rising in US, highlighting need for clinical guidelines

Key takeaways:

• The prevalence of U.S. residents who used medical cannabis was 1.2% in 2013-2014 vs. 2.5% in 2019-2020.
• Researchers said a surveillance system is needed to assess the long-term effects of medical cannabis use.

The prevalence of medical cannabis use in the United States has increased significantly from 2013 to 2020, according to study results published in the American Journal of Preventive Medicine.

Taeho Greg Rhee, PhD, FACE, an assistant professor of medicine and public health at Yale University, and Robert A. Rosenheck, MD, a professor of psychiatry and of health policy and affiliated faculty at the Yale Institute for Global Health, wrote that medical cannabis has been legalized in 37 states in the United States as well as the District of Columbia.

The researchers conducted a study to evaluate correlates and temporal trends of medical cannabis use in the U.S. They used data from the 2013 to 2020 National Survey on Drug Use and Health (NSDUH), which includes a question asking those who had used cannabis in the past 12 months whether any cannabis use was recommended by a physician. They then used a modified Poisson model to approximate the average annual percent change (AAPC) of medical cannabis use from 2013 to 2020 and repeated the analyses for key sociodemographic and clinical subgroups.

Rhee and Rosenheck found a continued national increase in medical cannabis use for a variety of medical purposes 2 decades after the first state passed legalizing legislation.

In 2013 to 2014, the prevalence of U.S. residents who used medical cannabis was 1.2%. In 2019 to 2020, the prevalence was 2.5%, with an AAPC of 12.9% (95% CI, 10.4-15.5). In the multivariable-adjusted model, residing in a state where medical cannabis was legalized was significantly linked to greater odds of medical cannabis use (adjusted OR = 4.1; 95% CI, 3.68-4.56).

The researchers additionally noted that many of the clinical subgroups and sociodemographic groups studied indicated similar significant increases in medical cannabis use. The clinically relevant subgroups that saw significantly greater odds of medical cannabis use included: use of non-prescription pain relievers, poorer self-rated health statuses, cocaine use disorder and a past-year major depressive episode.

“The association of medical cannabis use with depression, cocaine use disorder, and nonmedical use of pain relievers suggests that it may have either been prescribed for those conditions or used on patient initiative for these problems,” the researchers wrote. “Because NSDUH is cross-sectional, the findings cannot establish temporality.”

Rhee and Rosenheck concluded that “substantially increased use of cannabis for medical purposes warrants further research to assess its diverse potential benefits and risks.” Additionally, they noted two “important implications of the persistent increase in medical cannabis use nationally.”

First, medical cannabis is assumed to be primarily used for chronic pain, MS or for nausea among patients with terminal illnesses. However, “there is a wide variation of qualifying medical or psychiatric conditions across states,” they wrote.

“Further, there is no consensus across the states or strong therapeutic evidence to support medical cannabis use for specific conditions (e.g., arthritis),” they wrote. “Because medical cannabis use is increasing in the US, clinical practice guidelines should be developed with evidence-based principles to follow in counseling patients about medical cannabis use.”

Second, Rhee and Rosenheck noted the lack of available data on any long-term effects medical cannabis might have, “limiting understanding of the cumulative public health effects of medical cannabis use.”

“While cannabis does not generally lead to overdose deaths (in contrast to opioids), several unintended consequences (eg, developing psychosis and motor vehicle crashes) have been documented,” they wrote. “Given the increasing medical cannabis use coupled with use for recreational purposes, a comprehensive, longitudinal surveillance system is needed to determine long-term benefits and harms of medical cannabis use.”