Medical marijuana linked to rapid onset of cannabis use disorder

Obtaining a medical marijuana card for chronic pain, insomnia, anxiety or depression led to a “rapid onset” of cannabis use disorder, according to researchers.

Moreover, they found no significant association between owning a medical marijuana card and improvements in pain, anxiety or depressive symptoms. The findings were published in JAMA Network Open.

“Our study underscores the need for better decision-making about whether to begin to use cannabis for specific medical complaints, particularly mood and anxiety disorders, which are associated with an increased risk of [cannabis use disorder (CUD)],” Jodi Gilman, PhD, an associate professor of psychiatry at Harvard Medical School, said in a press release. “There needs to be better guidance to patients around a system that currently allows them to choose their own products, decide their own dosing, and often receive no professional follow-up care.”

Gilman and colleagues conducted a pragmatic, single-site, single-blind randomized clinical trial to evaluate the effect of obtaining a medical marijuana card on target clinical and CUD in adults reporting symptoms of chronic pain, insomnia, anxiety or depression. From July 1, 2017, to July 31, 2020, they enrolled 186 adults aged 18 to 65 years (mean age, 37.2 years; 65.6% women) who were living in the Greater Boston area.

The participants were randomly assigned 2:1 to an immediate card acquisition group (n = 105) or a delayed card acquisition group (n = 81). Participants in the immediate card acquisition group were allowed to obtain a medical marijuana card right away, while those in the delayed card acquisition group waited 12 weeks to obtain a card.

Within the 12 weeks, the immediate card acquisition group had more CUD symptoms compared with the delayed card acquisition group (mean difference = 0.28; 95% CI, 0.15-0.4), according to the researchers. Also, participants in the immediate card acquisition group had fewer self-rated insomnia symptoms (mean difference = – 2.9; 95% CI, – 4.31 to – 1.51) but experienced no significant changes in pain severity or anxiety or depressive symptoms.

Gilman and colleagues further reported that the immediate card acquisition group had a higher incidence of CUD during the intervention than the delayed acquisition group (17.1% vs 8.6%; adjusted OR = 2.88; 95% CI, 1.17-7.07). Most of those who developed CUD sought a medical marijuana card for affective symptoms.

Overall, 28.3% of participants with anxious or depressive symptoms in the immediate card acquisition group experienced CUD during the study period compared with 10.8% of participants in the delayed card acquisition group. The odds of developing CUD were almost 2.9-fold higher in the immediate card acquisition group, according to the researchers.

Although most participants developed mild CUD, with 2 to 4 symptoms, the researchers noted that the symptoms developed “over a short, 12-week initial exposure.” The most common CUD symptoms included higher tolerance and continued use “despite the recurrent physical or psychological problems caused or exacerbated by cannabis,” the researchers wrote.

“These data suggest that a medical marijuana card may pose a high risk or may even be contraindicated for people with affective disorders,” Gilman and colleagues wrote. “This finding is important to replicate because depression has been reported as the third most common reason that people seek a medical marijuana card.”

References:

Gilman JM, et al. JAMA Netw Open. 2022;doi:10.1001/jamanetworkopen.2022.2106.

Marijuana for medical use may result in rapid onset of cannabis use disorder. https://www.massgeneral.org/news/press-release/Marijuana-for-medical-use-may-result-in-rapid-onset-of-cannabis-use-disorder. Published March 18, 2022. Accessed March 18, 2022.