Medical marijuana cards often sought by existing heavy users

"Making medical marijuana cards easy to obtain for vaguely defined mental or physical health conditions that are not supported by any research evidence has potential for those who use more heavily to claim need for a medical marijuana card solely to have easier access," says lead author Eric R. Pedersen, Ph.D., of the RAND Corporation in Santa Monica, Calif.

These results have implications for states that have legalized medical marijuana or are considering such legislation. Policymakers, according to the authors, should "design medical marijuana programs in their states that allow card acquisition only for people with mental and physical health problems that have documented evidence of medicinal benefit."

The researchers analyzed data from a long-term study of substance use prevention in California. Beginning in 2008, participants were followed from middle school through young adulthood. For the current investigation, the study contained data from 264 participants who were 18 to 20 years old in 2015 to 2017, when medical marijuana was legal in California but before outlets in that state were allowed to sell legal recreational marijuana beginning January 2018.

All participants had to have used marijuana at least once in the past month at the beginning of the study, but none had obtained a "medical marijuana card," which would allow them to buy, possess and use marijuana. Both initially and one year later, they were asked about their marijuana use, symptoms of depression and anxiety, and physical health problems.

At the one-year follow-up, 19 percent of participants had sought out and received a medical marijuana card. Overall, men were 2.91 times as likely as women to have received a medical marijuana card at follow-up.

In addition, for every additional day of marijuana use at the beginning of the study, the odds of receiving a medical marijuana card one year later increased by 7%. After statistically controlling for confounding variables, the authors found that physical and mental health problems at baseline (i.e., the problems ostensibly one would seek a medical marijuana card for) were not significant predictors of receiving a card in that follow-up period.

"It seems that more frequent use of marijuana, and not the physical and mental health problems that one ostensibly seeks a medical marijuana card to address, is what drives acquisition of a medical marijuana card," Pedersen says.

The authors note that their study does have limitations. Because this was a retrospective analysis of previously reported data, the researchers were unable to specifically ask participants the reasons they may have sought medical marijuana. Further, the timeframe may have been too short, and a more detailed and longer analysis may allow a better understanding of who seeks medical marijuana and why.

"Many individuals . . . struggle with legitimate medical and psychological concerns that can benefit from medical marijuana," according to the authors. In California, the specific qualifying conditions include chronic pain, glaucoma, AIDS, and seizures, among others. However, the law is also general enough that providers are allowed to recommend the drug to patients with "any other chronic or persistent medical symptom" that may limit "major life activities."

"It's not clear to us what participants are telling providers," Pedersen says, "but we suspect that under this catch all, you can get a recommendation pretty easily."

He adds that providers should consider reviewing forms of symptom management other than, or in addition to, marijuana and look for signs that the drug has impacted patients in a negative way.

And as more states consider legalizing medical marijuana, policymakers should be aware of both the favorable and adverse outcomes.

"In another paper, we found that young adults who had a medical marijuana card were more likely to report heavy use, greater consequences from use, selling marijuana, and driving under the influence of marijuana compared to young adults who did not have a card," Pedersen says.