Introduction
Despite advances in disease-modifying therapy for multiple sclerosis (MS), many people with MS continue to struggle with symptom management. Cannabis-based products, including synthetic tetrahydrocannabinol (THC), oromucosal sprays like nabiximols (Sativex®) and oral cannabis extracts with varying THC-to-cannabidiol ratios, have emerged as complementary treatments for symptom relief [1]. Some of these products have demonstrated efficacy in alleviating spasticity and neuropathic pain [2, 3], with potential benefits for urinary incontinence and sleep disturbances [4-6], while also exhibiting distinct safety profiles compared to conventional symptomatic treatments in MS [7]. However, use patterns of cannabis-based products, including prevalence, product types and determinants of use, may vary widely depending on regulatory and healthcare settings [8]. In Switzerland, these aspects remain uncharacterised. A clearer understanding is crucial to maximising potential therapeutic benefits, minimising risks and managing healthcare costs effectively, ultimately improving patient care.
In recent years, Switzerland’s regulatory framework for medical cannabis has evolved, facilitating access to cannabis-based products under medical supervision. In 2013, nabiximols became the first, and remains the only, cannabis-based product approved for the treatment of spasticity in MS in Switzerland [9]. In 2022, the Federal Office of Public Health removed the requirement for prior exemption approval for prescribing cannabis-based products, allowing physicians to prescribe nabiximols and compounded cannabis formulations directly [10]. Despite these changes, access remains limited due to strict prescribing criteria for nabiximols, THC content restrictions for compounded products and financial barriers, as mandatory insurance covers prescribed cannabis-based products only in exceptional cases [11]. Consequently, people with MS may turn to the informal market for cannabis-based products, increasing the risks of unsupervised use, incorrect dosing, adverse effects and exposure to unsafe products [2, 5].
Beyond regulatory and financial aspects, patient characteristics also influence cannabis-based product use by people with MS, though how these factors may impact use in Switzerland remains unclear. International studies suggest that younger people with MS, men, those with lower income, greater disability, severe spasticity or chronic pain, and those unmarried are more likely to use cannabis-based products [6, 12, 13]. Furthermore, dissatisfaction with conventional treatments or preference for holistic approaches may drive people with MS to use complementary therapies, including cannabis-based products [14, 15]. Understanding these factors within Switzerland’s specific healthcare and regulatory context is essential for ensuring appropriate access and use of cannabis-based products.
To address gaps in the literature, we analysed patterns of cannabis-based product use among people with MS enrolled in the Swiss Multiple Sclerosis Registry. We estimated the prevalence of use, identified associated factors and described user characteristics. Additionally, we examined cannabis-based product forms, prescription status and cost coverage over time to assess the potential impact of recent regulatory changes.
Methods
Data source and study population
Self-reported data from the Swiss Multiple Sclerosis Registry were used for this study. The Swiss Multiple Sclerosis Registry is an ongoing, rolling-enrolment study that recruits people with MS who are at least 18 years old and either live in or receive treatment in Switzerland. Participation is voluntary and requires a signed informed consent form as well as confirmation of an MS diagnosis or clinically isolated syndrome. Participants complete baseline and follow-up surveys, which are available online and in paper format in three languages: German, French and Italian. Further details are available elsewhere [16, 17].
This study used Swiss Multiple Sclerosis Registry baseline and follow-up questionnaires, analysed separately as two independent analyses with distinct objectives and outcomes.
Baseline data and outcomes
The baseline questionnaire, administered at enrolment, collected extensive sociodemographic, health and MS-related information, including cannabis-based product use. Baseline data collected from the start of the Swiss Multiple Sclerosis Registry in 2016 to October 2024 (the data collection cut-off for this study) were used to estimate the prevalence of cannabis-based product use (the primary outcome). Secondary outcomes in the baseline data analysis included identifying factors associated with cannabis-based product use and estimating the predicted probability of cannabis-based product use across different age groups. To be included in this analysis, participants had to have a confirmed MS diagnosis and available data on cannabis-based product use. Participants with clinically isolated syndrome and those with missing data on cannabis-based product use were excluded. All eligible participants constituted the baseline analysis sample, henceforth referred to as the total sample, while those with complete data on all variables tested for association with cannabis-based product use formed the complete case sample.
Follow-up data and outcomes
Data from five follow-up questionnaires, administered at 6- to 12-month intervals between 2018 and 2023, constituted the follow-up dataset and were analysed to explore how cannabis-based products were used. The 2021 questionnaire was excluded from analysis because the Swiss Multiple Sclerosis Registry survey was modified that year to address the COVID-19 pandemic and omitted questions about the use of cannabis-based products. The primary outcomes at follow-up were the most frequently used forms of cannabis-based products, prescription status and reimbursement methods. The secondary outcome was changes in cannabis-based product use patterns across the five follow-up waves. For inclusion in the follow-up data analysis, participants needed to report their MS subtype and actively use cannabis-based products. At each follow-up assessment, we excluded participants who were non-users, had incomplete data on cannabis-based product use or reported clinically isolated syndrome.
All questions from the Swiss Multiple Sclerosis Registry surveys that were used are provided in the appendix.
Outcomes of interest
The outcomes of interest included self-reported use of cannabis-based products (including the initiator of use), the forms of used products, prescription status and payment sources for prescribed products. Participants who indicated non-use were prompted to skip the related questions.
Use of cannabis-based products and initiative
Use of cannabis-based products was assessed in both the baseline and follow-up questionnaires using a multiple-choice question with the following response options: “No”, “Yes, on my own initiative” and “Yes, in consultation with a doctor”. At baseline, this referred to current use, whereas in follow-ups it pertained to use within the last six months. In cases where participants did not answer the question about cannabis-based product use, but responded to a subsequent question on the form of the cannabis-based product used, a separate category – “Yes, initiation unknown” – was introduced. For the purposes of defining cannabis-based product users and non-users at both baseline and follow-up, a simplified binary variable (Yes/No) was created by merging “Yes, on my own initiative”, “Yes, in consultation with a doctor” and “Yes, initiation unknown” into a single “Yes” category.
Forms of cannabis-based products
The forms of cannabis-based products used were assessed during follow-up using a multiple-choice question that listed various products (e.g. nabiximols, cannabis oil and cannabidiol-only products). This variable was treated as categorical, and the follow-up data were used to describe temporal trends in the forms of cannabis-based products used.
Prescription status of cannabis-based products
Follow-up questionnaires assessed whether the cannabis-based product used was prescribed by a doctor. Response options were “Yes” or “No” and this variable was treated as categorical and reported at each follow-up.
Cost coverage for prescribed cannabis-based products
Cost coverage for cannabis products prescribed by a doctor was assessed in the follow-up questionnaires using a multiple-choice question. The available options included “Self-payment”, “Health insurance” and “Other”, along with an open-text field for comments. In early follow-up questionnaires, responses were collected only as open-text entries. These responses were subsequently analysed and reclassified into the predefined categories and a new category, “Both self-payment and health insurance”, was created. This variable was treated as categorical and follow-up data were used to describe temporal trends in payment sources over time.
Variables of interests
Sociodemographic, health- and MS-related characteristics, along with the year of questionnaire completion, were used to describe the sample and explore potential associations with the use of cannabis-based products.
Sociodemographic variables were recorded at baseline and included sex (binary: Female / Male), highest education level (categorical: Did not complete mandatory schooling / Mandatory schooling / High school / Apprenticeship, higher professional education / University or applied university degree) and age in years (continuous), which was calculated separately at baseline and at each follow-up as the difference between the year of birth and the year of questionnaire completion.
Health- and MS-related characteristics were collected at baseline and each follow-up. MS duration in years (continuous) was calculated separately at baseline and each follow-up as the difference between the self-reported year of diagnosis and the year of questionnaire completion. MS subtype was determined using a multiple-choice question (categorical: Relapsing-remitting MS / Primary progressive MS / Secondary progressive MS). Furthermore, the presence of MS symptoms was assessed through a multiple-choice question listing various symptoms – such as visual disturbances, fatigue and spasms – with each symptom treated as a separate binary variable (Yes/No). Additionally, a summary symptom variable was created as a three-level categorical variable based on the number of reported symptoms (categorical: No symptoms / 1–5 symptoms / ≥5 symptoms). Gait disability was assessed using the Self-Reported Disability Status Scale [18], a validated proxy for the Expanded Disability Status Scale, based on three multiple-choice questions on mobility (categorical: Mild/Moderate/Severe gait disability). Use of disease-modifying therapies was assessed through a multiple-choice question listing both generic and commercial drug names and was treated as a binary variable (Yes/No). The presence of a chronic comorbidity was assessed using a multiple-choice question listing conditions like diabetes, hypertension, cancer, rheumatoid diseases, musculoskeletal disorders, depression and skin diseases (binary: Yes/No).
The year of questionnaire completion was recorded as a timestamp for online participants and as the year the questionnaires were returned to the Swiss Multiple Sclerosis Registry for participants using the paper format. This information was used to assess trends in cannabis-based product use over time.
Statistical analysis
To assess the prevalence of cannabis-based product use, we reported the frequency and percentage of Swiss Multiple Sclerosis Registry participants who reported cannabis-based product use at baseline. To characterise cannabis-based product users, we conducted a descriptive analysis of the baseline variables, reporting counts and percentages for categorical variables and summarising continuous variables using the mean and standard deviation. Additionally, we reported and descriptively compared prevalence of cannabis-based product users at each follow-up, along with the forms of cannabis-based products used, prescription status and cost coverage, using counts and percentages. We also analysed cannabis-based product forms by decision-makers/supervision over time.
To explore cross-sectional associations between cannabis-based product use and variables of interest, we applied multivariable logistic regression to the baseline data. The initial analysis was performed on a subset of participants with complete baseline data to determine the optimal model. The model was first fitted with all relevant variables, including individual MS symptoms, with cannabis-based product use as the outcome. Collinearity was assessed using generalised variance inflation factors (GVIF) adjusted for degrees of freedom. A GVIF value of 1 indicated no collinearity, while values above 5 suggested that the corresponding variable should be excluded [19]. Given the exploratory nature of this study, automated stepwise elimination based on the Akaike Information Criterion was used to identify a parsimonious model. However, sex, age, MS subtype, MS duration, education level and comorbidity presence were manually retained due to their established relevance for cannabis-based product use in the literature [6, 13], while pain and spasticity were retained as they represent the primary indications for nabiximols use [20].
Following model finalisation, multiple imputation was applied to the total sample to address missing data, under the missing at random assumption. Imputation was performed using predictive mean matching for continuous variables (disease duration), logistic regression for binary variables (individual MS symptoms, disease-modifying therapy use, comorbidity) and polytomous regression for categorical variables (symptom severity, MS subtype, gait disability, education). Ten imputed datasets were generated. Convergence was assessed by inspecting trace plots of the imputation chains, and the distribution of imputed values was compared against observed values to verify plausibility. Regression analyses were rerun on each imputed dataset and pooled. Odds ratios (OR) and 95% confidence intervals (CI) are reported for both complete case and imputed analyses as a mutual sensitivity check.
To estimate the probability of cannabis-based product use across different ages, we used the multivariable logistic model estimates from both the complete case and imputed analysis, as a mutual sensitivity check. A reference dataset was generated in which age ranged continuously from the minimum to maximum observed age in the sample, while all other variables included in the final model were held at their mode (for categorical variables) or mean (for continuous variables). Predicted probabilities and their 95% confidence intervals were derived from each model using conditional prediction, applied to the reference dataset described above.
All analyses were conducted using R (version 4.5.2, GPL-2/GPL-3 licence) [17], with the following packages: data.table version 1.17.18, haven version 2.5.5, openxlsx version 4.2.8.1 for data management, ggplot2 version 4.0.0 for data visualisation, mice version 3.19.0 for multiple imputation and car version 3.1-5 for collinearity assessment, hmisc version 5.2-5 for logistic regression, and labelled version 2.15.0 and gtsummary version 2.5.0 for tables. The analytical code is available from the corresponding author on reasonable request.
Ethics approval
The study was approved by the Ethics Committee of Zürich Canton (PB-2016-00894; BASEC-NR 2019-01027).
Results
By the data cut-off, 2246 people with MS had completed the baseline Swiss Multiple Sclerosis Registry questionnaire. Of these, 53 (2.4%) did not respond to the cannabis-based product use question and were excluded, leaving a final study sample of 2193. An additional 385 participants lacked data on at least one of the variables of interest and were excluded from the complete case analysis, resulting in a final complete case sample of 1793 (figure 1). Table 1 summarises participant characteristics at baseline by cannabis-based product use.
Follow-up analyses included 469 participants who used cannabis-based products, contributing 876 responses across five follow-up waves, with sample size per wave ranging from 108 to 265 (figure 1). Of these, 239 participants contributed to only one wave, 118 to two waves and 112 to three or more waves.
Cannabis-based product use and supervision
At baseline, 14.4% of participants (n = 330) reported current use of cannabis-based products. This proportion varied by the year in which the baseline questionnaire was completed, with the lowest rate observed in the first year of the Swiss Multiple Sclerosis Registry (12.2%) and the highest in 2022 (25.6%, tables S1 and S2 in the appendix). Among cannabis-based product users, 63.7% of participants reported initiating use independently, while 36.0% indicated using cannabis-based products in consultation with their physician (data missing for 0.4% participants).
Compared to non-users, participants who used cannabis-based products were more often male, more likely to have progressive MS, exhibited higher levels of gait disability, more often reported experiencing five or more MS-related symptoms concurrently and more frequently had chronic comorbidities (table 1). Participants who used cannabis-based products reported higher frequencies of all individual symptoms, with the most notable differences in pain (reported by 45.8% of users vs 25.1% of non-users) and spasms (50.6% vs 25.8%) (table S3 in the appendix).
Table 1: Characteristics of participants at baseline by cannabis-based product use in total and complete cases samples. Missing values reflect observed data prior to imputation. Multiple imputation was applied exclusively for regression analysis and is not reflected in the descriptive statistics presented in this table.
| Complete cases (n = 1793) | Total sample (n = 2193) | ||||
| Variable | Yes n = 267 | No n = 1526 | Yes n = 330 | No n = 1863 | |
| Sex, n (%) | Female | 173 (64.8%) | 1133 (74.2%) | 218 (66.1%) | 1384 (74.3%) |
| Male | 94 (35.2%) | 393 (25.8%) | 112 (33.9%) | 479 (25.7%) | |
| Language region, n (%) | German | 221 (82.8%) | 1210 (79.3%) | 271 (82.1%) | 1456 (78.2%) |
| French | 38 (14.2%) | 257 (16.8%) | 49 (14.8%) | 332 (17.8%) | |
| Italian | 8 (3.0%) | 59 (3.9%) | 10 (3.0%) | 75 (4.0%) | |
| Age in years, mean (SD) | 48 (12) | 46 (13) | 49 (13) | 46 (13) | |
| Years since diagnosis, mean (SD) | 11 (10) | 10 (9) | 12 (10) | 10 (10) | |
| Missing | 7 (2.2%) | 28 (1.5%) | |||
| MS subtype, n (%) | Relapsing-remitting MS | 161 (60.3%) | 1160 (76.0%) | 172 (52.1%) | 1245 (66.8%) |
| Primary progressive MS | 29 (10.9%) | 95 (6.2%) | 33 (10.0%) | 111 (6%) | |
| Secondary progressive MS | 77 (28.8%) | 271 (17.8%) | 95 (28.8%) | 309 (16.6%) | |
| Missing | 30 (9.1%) | 198 (10.6%) | |||
| Number of symptoms, n (%) | 0 | 11 (4.1%) | 235 (15.4%) | 11 (3.3%) | 280 (15.0%) |
| 1–5 | 100 (37.5%) | 783 (51.3%) | 126 (38.2%) | 960 (51.5%) | |
| >5 | 156 (58.4%) | 508 (33.3%) | 190 (57.6%) | 618 (33.2%) | |
| Missing | 3 (0.9%) | 5 (0.3%) | |||
| Disease-modifying therapy use, n (%) | No | 80 (30.0%) | 318 (20.8%) | 106 (32.1%) | 407 (21.8%) |
| Yes | 187 (70.0%) | 1208 (79.2%) | 220 (66.7%) | 1439 (77.2%) | |
| Missing | 4 (1.2%) | 17 (0.9%) | |||
| Comorbidity, n (%) | No | 112 (41.9%) | 774 (50.7%) | 138 (41.8%) | 903 (48.5%) |
| Yes | 155 (58.1%) | 752 (49.3%) | 185 (56.0%) | 898 (48.2%) | |
| Missing | 7 (2.1%) | 62 (3.3%) | |||
| Education, n (%) | Did not complete mandatory schooling / Mandatory schooling / High school / Apprenticeship | 147 (55.1%) | 837 (54.8%) | 180 (54.5%) | 983 (52.8%) |
| Higher professional education | 51 (19.1%) | 240 (15.7%) | 61 (18.5%) | 292 (15.7%) | |
| University or applied university | 69 (25.8%) | 449 (29.4%) | 83 (25.2%) | 560 (30.1%) | |
| Missing | 6 (1.8%) | 28 (1.5%) | |||
| Gait disability, n (%) | Mild | 143 (53.6%) | 1172 (76.8%) | 168 (50.9%) | 1382 (74.2%) |
| Moderate | 88 (33.0%) | 280 (18.3%) | 104 (31.5%) | 341 (18.3%) | |
| Severe | 36 (13.5%) | 74 (4.8%) | 45 (13.6%) | 93 (5.0%) | |
| Missing | 13 (4.0%) | 47 (2.5%) | |||
SD: standard deviation; MS: multiple sclerosis
Throughout follow-up, the proportion of survey respondents who had used cannabis-based products within the last 6 months of survey completion remained stable at around 20% (22.4%, 22.0%, 23.1% and 20.4% between 2018 and 2022, respectively [2021 excluded}), with a slight decline in the final follow-up in 2023 (17.4%). Characteristics of the participants who used cannabis-based products were largely consistent across follow-ups, though a slightly higher percentage used disease-modifying therapies in later follow-ups, while relapsing-remitting MS prevalence among users declined (table S4 in the appendix).
Factors associated with the use of cannabis-based products
In addition to the fixed independent variables, the final multivariable logistic regression model also included dysphagia, pain, spasms, epilepsy, tremor, total symptom count and gait disability. Estimates from the imputed analysis closely matched those from the complete case analysis (table 2).
Table 2: Multivariable logistic regression derived odds ratios and 95% confidence intervals in complete cases and imputed analysis.
| Characteristic | Complete cases analysis (n = 1793) | Imputed analysis (n = 2193) | |||
|---|---|---|---|---|---|
| OR | 95% CI | OR | 95% CI | ||
| Sex | Female | Ref. | Ref. | Ref. | Ref. |
| Male | 1.44 | 1.06–1.96 | 1.39 | 1.06–1.84 | |
| Age (years) | 0.98 | 0.96–0.99 | 0.98 | 0.97–0.99 | |
| Education | Did not complete mandatory schooling / Mandatory schooling / High school / Apprenticeship | Ref. | Ref. | Ref. | Ref. |
| Higher professional education | 1.23 | 0.83–1.78 | 1.13 | 0.80–1.59 | |
| University or applied university | 1.02 | 0.73–1.42 | 0.91 | 0.67–1.23 | |
| MS subtype | Relapsing-remitting MS | Ref. | Ref. | Ref. | Ref. |
| Primary progressive MS | 1.14 | 0.64–1.97 | 1.19 | 0.72–1.96 | |
| Secondary progressive MS | 1.14 | 0.73–1.76 | 1.25 | 0.83–1.89 | |
| Time since diagnosis (years) | 1.00 | 0.98–1.02 | 1.00 | 0.99–1.02 | |
| Disease-modifying therapy use | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 0.68 | 0.49–0.95 | 0.70 | 0.52–0.95 | |
| Gait disability | Mild | Ref. | Ref. | Ref. | Ref. |
| Moderate | 2.05 | 1.39–3.01 | 1.77 | 1.25–2.52 | |
| Severe | 2.76 | 1.56–4.85 | 2.40 | 1.42–4.05 | |
| Number of symptoms | 0 | Ref. | Ref. | Ref. | Ref. |
| 1–5 | 2.20 | 1.19–4.48 | 2.57 | 1.35–4.91 | |
| >5 | 2.41 | 1.19–5.24 | 2.71 | 1.33–5.52 | |
| Dysphagia | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 2.02 | 1.27–3.17 | 1.67 | 1.10–2.53 | |
| Pain | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 1.48 | 1.07–2.05 | 1.63 | 1.22–2.18 | |
| Spasms | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 1.59 | 1.13–2.23 | 1.62 | 1.20–2.18 | |
| Depression | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 1.47 | 1.00–2.14 | 1.23 | 0.87–1.75 | |
| Epilepsy | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 0.28 | 0.04–1.21 | 0.84 | 0.27–2.63 | |
| Comorbidity | No | Ref. | Ref. | Ref. | Ref. |
| Yes | 1.20 | 0.89–1.61 | 1.09 | 0.84–1.43 | |
| Year of questionnaire | 1.19 | 1.11–1.29 | 1.12 | 1.06–1.19 | |
CI: confidence interval; MS: multiple sclerosis; OR: odds ratio.
The probability of cannabis-based product use is estimated to decline with age, starting around 0.1–0.13 at younger ages and falling below 0.05 by age 70, with minimal differences between MS subtypes, slightly higher in progressive MS and lower in relapsing-remitting MS (figures S1 and S2 in the appendix).
Forms of cannabis-based products
A variety of cannabis-based products were used, with at least 66.7% of all reports indicating use of a THC-containing product, including alongside cannabidiol products (product type was missing for 93 of 876 observations throughout the follow-up). Cannabidiol was the predominant form used in 2018–2022, peaking at around 40% of all cannabis-based products used in 2019–2020 before declining to 25% by 2023. Conversely, nabiximols showed a steady increase from 20% in 2018 to 30% in 2023, becoming the most commonly used cannabis-based product in 2023. Other forms maintained relatively stable usage patterns throughout the study period (figure 2). When analysed by supervision status, nabiximols was the cannabis-based product most frequently used in consultation with a doctor, followed by cannabidiol and tinctures. In contrast, use of cannabis-based products initiated independently by participants primarily involved cannabidiol products, oil and street cannabis (figure S2 in the appendix).
Prescription status and cost coverage
Across the first three follow-up surveys, approximately 30% of participants reported that their use of cannabis-based products was medically prescribed; this proportion increased to 40% in the final two follow-up surveys (table S5 in the appendix). Among the prescribed products, the majority were covered by health insurance – 76%, 81%, 83% and 81% across the first four follow-ups – with health insurance cost coverage rising to 93% in the final follow-up. At the same time, the proportion of costs paid by participants declined. A smaller number of participants reported other sources of coverage for their prescribed cannabis-based products, such as disability insurance or manufacturer-sponsored test samples (figure 3, table S6 in the appendix).
Discussion
In this study of 2193 people with MS in Switzerland, we observed that up to one-quarter of participants reported using cannabis-based products between 2016 and 2023. Participants who used cannabis-based products were more often male, had a higher number of comorbidities and more frequently reported having progressive MS forms and experiencing five or more MS-related symptoms concurrently compared to non-users. Greater disease burden, reflected by increased symptom load and gait impairment, as well as male sex, were positively associated with the use of cannabis-based products. While cannabidiols were initially the most commonly used cannabis-based products, nabiximols emerged as the predominant product by 2022. This coincided with a 10% increase in prescribed cannabis-based products and health insurance coverage rising to over 90%.
The prevalence of cannabis-based product use among people with MS in Switzerland appears substantially higher than in the general Swiss population. National data indicate that 30-day cannabis use in the general population was estimated at only 2.7% in 2015 [21], while a separate study using self-reports and wastewater analysis in western Switzerland found 12-month prevalence of cannabis to be 9.4% [22]. Cannabidiol use, legal in Switzerland since 2016, showed a 12-month prevalence of 18.5% among young Swiss men [23]. In contrast, our study found that the prevalence of current cannabis-based product use among people with MS was 14.4%, with use within the previous 6 months reaching up to 23% at follow-ups – higher than in the general population, which mirrors the situation in Italy and the US [24, 25]. This suggests that cannabis-based products may play a distinct and more prominent role among people with MS, likely driven by unmet symptom management needs and enabled by improved access to regulated cannabis-based products.
Our estimates of the prevalence of cannabis-based product use align with those of existing international studies. Recent research from France and Spain found that 23.3% and 20.1%, respectively, of people with MS reported using cannabis and/or formulations such as nabiximols or cannabidiol-rich oils [12]. Data from Canada, the UK and Spain prior to widespread availability of nabiximols indicated higher rates of ever-use of cannabis, exceeding 35–40%, although current use remained lower (between 14% and 18.5%) [13, 26, 27]. The small gap between current and recent use in our cohort suggests that more participants may have tried cannabis-based products in the past but discontinued them, possibly due to adverse effects, loss of efficacy or varying availability and cost [28-30].
Consistent with prior studies, our data revealed that cannabis-based product use was more common among men, younger participants and individuals with greater disability and symptom burden [12, 25, 26], as well as in participants with pain, spasms and dysphagia. This supports the idea that cannabis-based product use is primarily driven by symptom severity [4, 12], particularly in cases where conventional treatments offer limited relief, such as spasticity and pain [26]. Notably, these same symptoms are also those that people with MS perceive cannabis-based products to be most effective in managing [13]. However, the association with dysphagia likely reflects a more advanced disease, rather than a targeted therapeutic effect, as cannabis-based products are not indicated for dysphagia in MS or other conditions, and current evidence on cannabis-based products in gastrointestinal disorders does not extend to swallowing difficulties [31, 32].
The rise in prescribed cannabis-based products, primarily nabiximols, which supplanted non-prescription cannabidiols, and the increasing share of costs covered by health insurance point to a broader shift towards regulated, prescription-based access to cannabis-based products following the 2022 regulatory changes. While we cannot directly attribute these trends to the regulatory shift alone, they suggest that clearer policies may have supported greater physician prescribing and patient preference for medically supervised, reimbursable treatments.
However, this shift warrants careful evaluation from both equity and clinical perspectives. If reimbursement relies primarily on supplementary rather than mandatory health insurance, access is likely to follow socioeconomic gradients. This is particularly relevant given that people with MS who do not currently use cannabis-based products express willingness to do so when prescriptions are covered by insurance or otherwise legally accessible [2, 14, 20]. International experience shows that, with few exceptions, many patients worldwide continue to pay out-of-pocket costs [33], limiting access for those with lower socioeconomic status. Ensuring that use reflects appropriate, evidence-based practice is equally essential. Studies indicate that, although more than half of patients initiating nabiximols experience an initial treatment response, only around 40% achieve sustained, clinically meaningful improvement, and approximately half discontinue treatment within six months due to loss of effectiveness or adverse effects [20], primarily drowsiness, dizziness and fatigue [34]. These patterns underscore the importance of systematic monitoring to align prescribing practices with clinical evidence, which may be insufficient [35].
Switzerland’s regulatory environment may continue to evolve, with ongoing pilot programmes such as the Züri Can study exploring regulated recreational access to THC-containing cannabis-based products [36]. In neighbouring Germany, the 2017 law permitting physicians to prescribe cannabis for medical purposes, along with subsequent expansions in 2024 that broadened access, was followed by both increased interest in medical cannabis [37] and indications of a rise in adverse effects in the general population [38]. This highlights that potential policy changes expanding access to cannabis-based products require continuous, systematic monitoring of clinical effectiveness and safety, alongside evaluation of broader public health impacts [39]. Real-world data sources, including patient registries such as the Swiss Multiple Sclerosis Registry, can provide valuable evidence on nationwide use of cannabis-based products, therapeutic outcomes and disparities in access.
Strengths and limitations
To our knowledge, this is the first study to quantify and characterise the use of cannabis-based products among people with MS in Switzerland. By drawing on a diverse, nationwide sample, including people with MS treated in private practices, outpatient clinics and academic centres, our findings are likely generalisable to the broader Swiss MS population. The use of both baseline and follow-up data allowed for a more robust estimate of current and recent cannabis-based product use, as well as trends in product types and reimbursement. Nonetheless, several limitations should be considered. First, reliance on self-reported data might have introduced recall and social desirability biases, particularly regarding unsupervised cannabis-based products use. However, prior work suggests that Swiss Multiple Sclerosis Registry participants report disease-modifying therapy use reliably [40], which may extend to other treatments. Second, follow-up sample sizes varied across survey waves, primarily due to a shift in the Swiss Multiple Sclerosis Registry follow-up survey dissemination strategy in 2019 rather than marked changes in underlying participation. This variation may limit comparability across time points. In addition, some participants contributed data at multiple waves, and changes in disease status over time may have influenced cannabis-based product use patterns. Third, data on the safety and efficacy of cannabis-based products were not collected, preventing assessment of their clinical benefits or risks and limiting understanding of how these factors may have influenced patterns of use. Lastly, the observational design precludes causal inferences, and future longitudinal studies are needed to examine how MS progression and regulatory changes influence treatment uptake and outcomes.
Conclusions
This nationwide study is the first to quantify use of cannabis-based products among people with MS in Switzerland, revealing that up to one-quarter used cannabis-based products between 2016 and 2023 – more than in the general population, likely due to unmet symptom management needs and improved access. Cannabis-based product use was associated with male sex, younger age and greater disease burden, including presence of symptoms such as pain, spasticity and dysphagia. The increase in prescribed nabiximols and broader insurance coverage by 2023 suggests that recent policy changes may have encouraged a shift towards regulated, medically supervised use. These findings highlight the need for further patient-centred regulation and clinical oversight to ensure the safe and effective integration of cannabis-based products into MS care.
Data sharing statement
The datasets generated and analysed during the current study cannot be made publicly available due to the sensitive nature of the patient data and the terms of participant informed consent. Deidentified data and a data dictionary are available from the corresponding author on reasonable request, subject to Swiss Multiple Sclerosis Registry steering committee approval, applicable data protection regulations and a data sharing agreement specifying permitted use, access duration and data destruction conditions.