Claims about medical marijuana treating multiple mental health and neurological disorders may be overhyped, according to a new study investigating the effect of medical marijuana card ownership. The study was published in Psychiatry.
Medical cannabis has surged in popularity in recent years despite inconclusive evidence on its efficacy and little information on its risk. While cannabis has been reported to improve pain, sleep, anxiety, and depressive symptoms, research also shows that 30.6% of US adults who use cannabis develop cannabis use disorder (CUD).
In the present study, researchers recruited 186 patients aged between 18 and 65 reporting pain, insomnia, anxiety, or depressive symptoms. They were randomized on a ratio of 2:1 to either receive a medical marijuana card immediately or after 12 weeks.
Upon receiving a medical marijuana card, participants could choose which cannabis products to use from a dispensary alongside the dose and frequency of use. They could also continue to engage in their usual medical and psychiatric care strategies.
In the end, the researchers found that those who received a medical marijuana card immediately experienced significantly more CUD symptoms than those who received the card later on.
They also found that while those who received medical marijuana cards immediately experienced lower levels of insomnia than the other group, marijuana usage had no significant effect on pain, anxiety, or depressive symptoms across all participants.
"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," said lead author Jodi Gilman, PhD, with the Center for Addiction Medicine at Massachusetts General Hospital.
“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,” she added.
The researchers noted limitations to their findings. They did not measure the pharmacological effects of cannabis use during the study, and while they tracked the frequency of use, they were unable to track quantity or potency. They also noted that they did not have a placebo arm in their study, and as all participants sought cannabis as a potential treatment, they say that their results may suffer from a ‘treatment effect’.