Cannabis use for symptom relief in multiple sclerosis: A cross-sectional survey of webinar attendees in the US and Canada

Background: With the expansion of medical and recreational legalization of cannabis, there is growing interest in cannabis use by people with multiple sclerosis (MS). Research supports that cannabis relieves MS-related pain and spasticity, two common symptoms of MS. However, there is limited information available about cannabis use in people with MS across the United States and Canada. Methods: 1,015 people with MS in the US and Canada participated in an informational webinar on cannabis for the control of MS symptoms. Attendees were presented with three questions about their use of cannabis for MS symptoms and their knowledge of the medical legality of cannabis in their state. Demographics and MS characteristics were obtained from webinar registration. The legality of cannabis (not legal, legal for medical use only, and legal for recreational and medical use) and the number of years since medical legalization at the time of this webinar were determined for all states. Using logistic regression, we analyzed associations between individual characteristics (demographics, disease severity and legal status), cannabis use, and knowledge of legality. Results: Of the 1,015 webinar registrants, 54% (n = 548) answered the question, “Have you used marijuana in the past year to help control your MS symptoms?” and were included in the analyses. Statistically significant associations were seen between cannabis use and local legal status of cannabis (recreational vs. not legal: OR 4.55, 95% CI: [1.70–12.14], p = 0.002), years since medical legalization of cannabis (for each year since legalization: OR 1.06, 95% CI: [1.02 – 1.10], p = 0.004), disease severity (severe vs. mild disability: OR 3.41, 95% CI: [1.23 – 9.46] p = 0.018) and gender (male vs. female: OR 2.33, 95% CI: [1.10–4.94], p = 0.027). Accuracy of knowledge of local cannabis legality was significantly associated with cannabis use in the past year (users vs. non-users: OR 2.52, p = 0.014), local legal status of cannabis (medical only vs. not legal: OR 0.30, p = 0.001; recreational vs. not legal: OR 4.98, p = 0.039), years since legalization of cannabis (for each increased year since legalization: OR 1.15, p < 0.001), and country of residence (Canada vs. USA: OR 0.42, p = 0.021). Conclusions: This study supports that cannabis use for MS symptoms is more common in states where cannabis laws are more permissive and where cannabis has been legal for longer, in those with more severe MS, and in men. Accurate knowledge of local cannabis legality is more common in those who report using cannabis for their MS in the past year. Those living in states where cannabis is legal for medical use only are less likely to be aware of legal status than those in either recreationally-legal or non-legal states, but awareness of legal status increases with time since medical legalization. Canadians are less likely than Americans to be accurate in their perception of the legal status of cannabis.