Cannabis-based product use in multiple sclerosis: a Swiss nationwide, registry-based observational study

BACKGROUND: Cannabis-based products are commonly used to manage multiple sclerosis (MS) symptoms such as spasticity and pain. However, the prevalence of cannabis-based product use, types of products used and factors associated with use remain unexplored in the Swiss MS population. OBJECTIVE: To estimate the prevalence of cannabis-based product use, identify factors associated with use and characterise use patterns among people with MS enrolled in the Swiss Multiple Sclerosis Registry (SMSR). Additionally, we explored trends in cannabis-based product types, prescription status and insurance reimbursement over time. METHODS: This exploratory observational study analysed self-reported data collected between 2016 and 2024. Prevalence estimates and associated factors were assessed using descriptive statistics and multivariable logistic regression on participants’ baseline responses. Follow-up data from cannabis-based product users were analysed descriptively to evaluate temporal trends. RESULTS: Of the 2193 participants, 330 (14.4%) reported current cannabis-based product use at baseline. Use varied by year of baseline questionnaire completion, ranging from 12.2% in 2016 to 25.6% in 2022. Cannabis-based product use was positively associated with reporting five or more symptoms (odds ratio [OR]: 2.41, 95% confidence interval [CI]: 1.19–5.24), presence of dysphagia (OR: 2.02, 95% CI: 1.27–3.17), spasms (OR: 1.59, 95% CI: 1.13–2.23), pain (OR: 1.48, 95% CI: 1.07–2.05) and greater gait disability (OR: 2.05, 95% CI: 1.39–3.01 for moderate; OR: 2.76, 95% CI: 1.56–4.85 for severe vs mild). Male sex (OR: 1.44, 95% CI: 1.06–1.96) was associated with higher odds of cannabis-based product use, while older age (OR: 0.98 per year, 95% CI: 0.96–0.99) and use of disease-modifying therapies (OR: 0.68, 95% CI: 0.49–0.95) were associated with lower odds. Follow-up data from 469 cannabis-based product users, providing 876 responses, showed cannabidiol was the most frequently used product between 2018 and 2022 but declined from 40% of reported use in 2019–2020 to 25% in 2023. In contrast, nabiximols use increased from 20% in 2018 to 30% in 2023, becoming the most commonly used product. The proportion of prescribed cannabis-based products rose from approximately 30% to 40%, while insurance reimbursement increased from 76% to 93% over the follow-up period. CONCLUSIONS: Cannabis-based product use among people with MS exceeded rates seen in the general population in Switzerland. Higher symptom burden and greater disability may be key drivers of use. Increasing prescription and reimbursement rates over time suggest a shift towards more regulated, medically supervised use, likely influenced by evolving policy.