There is a clear need to study side effects of medical cannabis, which is not regulated by the Food and Drug Administration (FDA). An FDA drug review subjects medicines to safety evaluations, including a complete review of interactions with other drugs, side effects, and potential differences in effectiveness or safety among people of different genders, ages, and races. In contrast to medicines that undergo FDA review, medical cannabis, which was voted on at the ballot box, lacks information about the amount, or dose, people should take, safety of various medical marijuana products, effectiveness of various products for specific medical conditions, and side effects. How much medical cannabis is used, when, and how often, is largely left up to patients themselves. Little is known about the amount of cannabis needed to experience relief of symptoms, how long patients should use medical cannabis, or whether patients can substitute cannabis for other medications prescribed for their medical conditions. Perhaps most importantly, data is lacking on whether those who use medical cannabis daily for chronic conditions develop similar rates of addiction to those who use cannabis daily for recreational purposes.

Clinical trials, the gold standard in assessing whether a medicine works, have not examined side effects of medical cannabis such as cognitive effects or development of CUD. This is beginning to happen; for example, cannabidiol, or CBD, was approved by the FDA in 2016 in the form of a liquid called EPIDIOLEX® for the treatment of childhood epilepsy. EPIDIOLEX®, however, which is highly regulated and dosed, is quite different than medical cannabis purchased in a dispensary, which is unregulated. We may someday discover other therapeutic components of cannabis, which may eventually be useful for mental health treatment. However, until we have more evidence, we should take a cautious approach to using or recommending medical cannabis for mental health conditions.