Unprescribed cannabinoids and multiple sclerosis: a multicenter, cross-sectional, epidemiological study in Lombardy,...

Cannabinoids are approved for spasticity and pain in multiple sclerosis (MS). In 2017 the prevalence of current users in the Italian general population was 10.2%, while data on Italian MS patients are limited.

From March 2022 to February 2023, we conducted a multicenter, cross-sectional study. Adult MS patients completed an anonymous online survey. The primary outcome was the estimated prevalence of unprescribed cannabis current use. Cannabis use patterns and associations with clinical and socio-demographical variables were investigated. The binomial method was used to estimate 95% confidence interval (95% CI) for primary outcome.

5620 patients were invited and 2024 (36.0%) were included (mean age 45.2 years, females 64.5%). Relapsing remitting form was the most frequent (77.3%). Median expanded disability status scale (EDSS) was 2.0. The proportion of current users was 15.5% (95% CI 13.9-17.1) and 36.4% of them disclosed to their physician their unprescribed cannabis use. 15.0% patients were former users while 69.5% never used cannabis. Current users more frequently reported a medical use (i.e., current medical users) compared to former users (p < 0.001). 41.1% of never users would use cannabis if it was legal. Young age, being male, and a free marital status were associated with current use. Current medical users had higher disability, spasticity and pain, reduced quality of life, concomitant neurological/psychiatric drugs and analgesics use. Unprescribed cannabis appeared relatively safe, with limited addiction risk, and reported clinical benefits, including concomitant medications reduction.

Unprescribed cannabis use is common in patients with MS in Italy, with observed prevalence seemingly superior to the general population, often intended for medical use and without the disclosure to the treating physician, although with potential clinical benefits.