Cannabis use more than doubled over the past decade among Americans 50 and over, with nearly one in 10 now reporting usage over the past year, an analysis of the National Survey on Drug Use and Health (NSDUH) found.

Of the 8.9% who reported using cannabis in the past year; roughly one in five (18.5%) reported using it for medical purposes such as treatment of chronic pain or depression, or for diseases like arthritis, reported Namkee Choi, PhD, and Diana DiNitto, PhD, both from University of Texas at Austin.

Compared to recreational users, those using cannabis for medical purposes were more likely to discuss drug use with a healthcare professional (adjusted OR 4.18, 95% CI 2.53-6.89), to purchase from a medical cannabis dispensary (aOR 4.38, 95% CI 2.47-7.76), and to report more frequent use (aOR 2.56, 95% CI 1.35-4.86), according to the research in the American Journal of Drug and Alcohol Abuse.

“The findings suggest that some medical users may be self-treating without healthcare professional consultation,” Choi said. “As part of routine care, healthcare professionals should screen for cannabis and other substance use, and for mental health problems, and recommend treatment when necessary.”

For their study, the researchers examined 2018 and 2019 NSDUH data involving 17,685 individuals ages 50 and up, 55% of whom were women. Of self-described medical cannabis users — which by NSDUH definition implies physician-recommended use – less than 40% reported discussing cannabis use with a healthcare provider, which the authors noted suggests that some reported medical use without a doctor’s recommendation, possibly because they believed it to be necessary for relieving their symptoms.

Indeed, Choi and DiNitto cited another large survey performed in the U.S. in 2017 that found the most common medical reasons for marijuana use were anxiety (49%), insomnia (47%), chronic pain (42%), and depression (39%). Among those using marijuana for medical purposes, 21% did not have a doctor. Among those with doctors, 33% did not inform them, 28% reported their doctor was neutral on their use, 32% reported their doctor was supportive, and 8% reported their doctor was not supportive.

In the current study, while medical users reported using cannabis more frequently, with 40% using it roughly 4 to 7 days per week, they were less likely to have alcohol use disorder compared with nonmedical cannabis users (aOR 0.39, 95% CI 0.20-0.76). Otherwise, medical and nonmedical users did not differ on physical and most behavioral health indicators, although cannabis users in general had significantly higher rates of alcohol use disorder, nicotine dependence, other illicit drug use, and mental illness compared with nonusers.

Most were experienced users rather than new to cannabis use; most obtained cannabis from private/informal sources, reportedly with little difficulty. Of self-reported medical users, 71% reported exclusive medical use; the rest reported both medical and nonmedical use.

It is important that patients be made aware of the risks of obtaining cannabis and cannabis products from unregulated sources, the authors noted. “Given the increase in THC [tetrahydrocannabinol] potency, healthcare professionals should educate older cannabis users, especially high-frequency users, on potential safety issues and adverse effects.”

In addition to urging doctors to do more to screen and educate their patients, the study authors say the NSDUH needs updating to “reflect changing cannabis product commercialization,” with cannabidiol, topical solutions, and edibles often available now.

In fact, there has been a push in recent years to help familiarize healthcare providers with the health effects of cannabis: Last year, citing a 2015 survey of healthcare providers, Nora Volkow, MD, director of the National Institute on Drug Abuse, concluded that providers “perceive a knowledge gap related to cannabis dosing, treatment plans, and different areas related to cannabis products, so providers themselves realize the need for research and expertise to be developed in this area.”

In the face of increasing patient requests, new guidelines have been issued on medical cannabis for chronic pain; and last fall, MedPage Today reported on the publication of Medical Marijuana: A Clinical Handbook.

Researchers noted that limitations of their study included the relatively small number of medical users and the fact some respondents may have under-reported their cannabis and other substance use.