Patterns of Use and Cannabis Use Disorder in Adults Using Cannabis for Medical Reasons

A total of 39 states and the District of Columbia have legalized the medical use of cannabis-containing products. Individuals now use cannabis to treat a wide array of physical and psychological symptoms, including pain, nausea, insomnia, anxiety, and depression; however, there is sparse data to support the efficacy of cannabis as a treatment for most of these conditions.  Furthermore, a study published in 2022 by Jodi Gilman, PhD and colleagues from the Center for Addiction Medicine at Mass General, indicated that procuring a card authorizing the use of cannabis for medical conditions may also increase risk for cannabis use disorder (CUD).

In order to determine whether frequency or patterns of cannabis use were associated with the development of CUD, the researchers prospectively followed a group of 149 participants using cannabis for the treatment of chronic pain, insomnia, anxiety or depressive symptoms who had completed the study mentioned above.  The participants were followed for a total of one year following the acquisition of a medical cannabis card, and CUD symptoms were assessed using the CUD Checklist for the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition).

Distinct Patterns of Use Predict Risk for Cannabis Use Disorder

Gilman and colleagues identified five unique trajectories of cannabis use during the first year after receiving a medical cannabis card; 31 participants (21%) reported low stable or no use (<1 day per week), 50 (34%) reported  medium stable use (1–4 days per week), 19 (13%) reported high stable use (5–7 days week), 26 (17%) showed de-escalating use and 23 (15%) showed escalating use.

Of the 149 enrolled participants, 19 (13%) met diagnostic criteria for CUD during the year after receiving a medical cannabis card. Only the escalating cannabis use pattern was associated with higher rates of CUD compared to the low or no use category (OR = 4.29, 95% CI = 1.21 to 10.87, p = 0.02).

Clinical Implications

The current study indicates that among adults using cannabis for medical reasons, most individuals either maintain (68%) or decrease (17%) their cannabis use over the first year.  However, there is a significant risk of developing new-onset cannabis use disorder in the year following the acquisition of a medical use card, and this risk appears to be the highest among the participants in this study who had an escalating pattern of use. 

Overall, about 13% of the adults using cannabis for medical reasons met criteria for CUD within the first year.  This rate is lower than the 30% risk of CUD observed in nationally representative samples of recreational users.  In this study, individuals with escalating use had about a fourfold increased risk of developing CUD.  The authors thus suggest that monitoring for escalating use may help identify those individuals at greater risk for CUD. 

Gilman JM, Potter K, Schuster RM, Hoeppner BB, Evins AE. Cannabis use for medical symptoms: Patterns over the first year of use. Addict Behav. 2023 Apr 13;144:107719. 

Medical marijuana may trigger substance abuse (The Harvard Gazette)

Study raises questions about risks of using medical marijuana for mood and anxiety disorders (CNN)