Cannabis use for medical symptoms: Patterns over the first year of use

•Individuals are increasingly using cannabis for medical symptoms.•We assessed patterns of cannabis use for one year after initiating medical cannabis use.•Most individuals using cannabis had a stable pattern of use over the first year.•Those with escalating cannabis use patterns were at higher risk of CUD.•Escalation of use may be a detrimental pattern in medical cannabis users. As greater numbers of states in the United States and countries in the world continue to legalize cannabis for medical use, it has become increasingly important to assess patterns of cannabis use in individuals using cannabis for medical symptoms over time. A public health concern is that, like recreational cannabis, some individuals using cannabis for medical reasons may develop detrimental patterns of use, leading to the development of a cannabis use disorder (CUD). In a 9-month longitudinal cohort study following a 12-week randomized, waitlist-controlled trial in 149 adults who used cannabis to alleviate insomnia, pain, depressed mood, or anxiety (RCT: NCT03224468), we assessed whether patterns of cannabis use for the 9 months following the RCT were associated with the development of CUD. We identified five unique trajectories of use; 31 participants (21%) had low stable or no use, 50 (34%) had medium stable use, 19 (13%) had high stable use, 26 (17%) showed de-escalating and 23 (15%) showed escalating use over 9 months following the RCT. Of 149 participants enrolled, 19 (13%) met diagnostic criteria for CUD at 12 months. Only the escalating cannabis use pattern predicted significantly 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). These data indicate that most individuals using cannabis for medical symptoms have a stable pattern of use over the first year. Escalation of use may be a detrimental pattern that warrants further concern.