Cannabis use among older adults is growing faster than any other age group, but many report barriers to getting medical marijuana, a lack of communication with their doctors, and a lingering stigma attached to the drug, according to researchers.

The study, the first to look at how older Americans use cannabis and the outcomes they experience, was published this month in the journal Drugs & Aging.

"Older Americans are using cannabis for a lot of different reasons," said study co-author Hillary Lum, MD, PhD, assistant professor of medicine at the University of Colorado School of Medicine. "Some use it to manage pain, while others use it for depression or anxiety."

The 2016 National Survey of Drug Use and Health showed a ten-fold increase in cannabis use among adults over age 65. The researchers set out to understand how older people perceived cannabis, how they used it, and the positive and negative outcomes associated with it.

They conducted 17 focus groups in in senior centers, health clinics, and cannabis dispensaries in 13 Colorado counties that included more than 136 people over the age of 60. Some were cannabis users, others were not.

"We identified five major themes," Lum said. These included: A lack of research and education about cannabis; a lack of provider communication about cannabis; a lack of access to medical cannabis; a lack of outcome information about cannabis use; a reluctance to discuss cannabis use.

Researchers found a general reluctance among some to ask their doctors for a red card to obtain medical marijuana. Instead, they chose to pay more for recreational cannabis. Lum said this could be driven by feeling self-conscious about asking a doctor for cannabis. That, she said, points to a failure of communication between health-care providers and their patients.

"I think [doctors can] be a lot more open to learning about it and discussing it with their patients," said one focus group respondent. "Because at this point I have told my primary care I was using it on my shoulder. And that was the end of the conversation. He didn't want to know why, he didn't want to know about effects, didn't want to know about side effects, didn't want to know anything."

Some said their doctors were unable or unwilling to provide a certificate, the document needed to obtain medical marijuana. They also said physicians need to educate themselves on the latest cannabis research.

Some older users reported positive outcomes when using cannabis for pain as opposed to taking highly addictive prescription opioids. They often differentiated between using cannabis for medical reasons and using it recreationally. "Although study participants discussed recreational cannabis more negatively than medical cannabis, they felt it was more comparable to drinking alcohol, often asserting a preference for recreational cannabis over the negative effects of alcohol," the study said.

The researchers also found that despite the legalization of cannabis in Colorado and other states, some older people still felt a stigma attached to it.

"Some participants, for example, referred to the movie Reefer Madness (1936) and other anti-marijuana propaganda adverts that negatively framed cannabis as immoral and illegal," the researchers said.

The study adds to the growing literature on the diversity of marijuana use patterns in older adults, said co-author Sara Honn Qualls, PhD, ABPP, professor of psychology and director of the Gerontology Center at the University of Colorado, Colorado Springs.

"Older adults who use marijuana are ingesting it in a variety of ways for multiple purposes," she said. "This and other papers from the same project show growing acceptance of marijuana use for medical purposes by older adults, and a clear desire to have their primary health providers involved in educating them about options and risks.

Lum agreed. She said Colorado, the first state to legalize recreational marijuana, provides a unique laboratory to gauge public attitudes toward cannabis. "From a physician's standpoint, this study shows the need to talk to patients in a non-judgmental way about cannabis," she said. "Doctors should also educate themselves about the risks and benefits of cannabis and be able to communicate that effectively to patients."

The study co-authors include Julie Bobitt, Melissa Schuchman, Robert Wickersham, Kanika Arora, Gary Milavetz, and Brian Kaskie.