Randomized trials failed to show objective improvement in MS spasticity with cannabinoids, but patients consistently reported significant subjective improvement in spasticity, spasms, sleep, and pain.
Read this if you have MS and are weighing the evidence for cannabis-based spasticity treatments.
No objective improvement, but significant patient-reported benefits for spasticity, spasms, sleep, and pain
What the researchers found
A structured critical appraisal examined whether cannabinoids improve MS-related spasticity.
The largest randomized placebo-controlled trial of oral cannabinoid therapy found no improvement on the Ashworth scale (an objective spasticity measure). However, patients reported significant improvement in spasticity (p=0.01), spasms (p=0.038), sleep quality (p=0.025), and pain (p=0.002) without worsening depression, fatigue, irritability, or walking.
A second RCT confirmed the same disconnect between objective and subjective outcomes.
The authors concluded that this raises important questions about whether current objective instruments are sensitive or valid enough to capture the clinical benefits patients experience.
Why it matters
The consistent disconnect between what objective scales measure and what patients experience suggests a measurement problem rather than a drug problem, with implications for how clinical trials should evaluate cannabis-based medicines.
The numbers in context
Ashworth scale: no significant improvement. Subjective spasticity: p=0.01. Spasms: p=0.038. Sleep: p=0.025. Pain: p=0.002. No worsening of depression, fatigue, irritability, or walk time.
How the study worked
Critically appraised topic developed by neurologists, epidemiologists, and MS specialists. Structured literature search and critical appraisal of the best available randomized controlled trial evidence.
What this study cannot tell us
Limited number of high-quality RCTs available. The Ashworth scale is known to have inter-rater variability. Subjective improvement could be influenced by psychoactive effects rather than true spasticity reduction.
How to read the evidence
Critical appraisal of existing RCT evidence by a multidisciplinary team. Quality limited by the available trial data.
When this study was published
Published in 2009. Sativex has since been approved for MS spasticity in multiple countries, and more sensitive outcome measures have been developed.
The bigger picture
This finding has been replicated across multiple cannabis-MS studies and contributed to regulatory decisions. Sativex was eventually approved for MS spasticity in multiple countries, with approval partly based on patient-reported outcomes.
Questions still open
- Should patient-reported outcomes carry more weight in spasticity trials? Do current objective measures miss clinically meaningful changes? Are the subjective benefits from direct spasticity improvement or from other effects (pain relief, sleep improvement)?
Common questions
Why would patients feel better if clinical measures do not improve?
Does this mean cannabinoids work for MS spasticity or not?
Read the original research
Do cannabinoids reduce multiple sclerosis-related spasticity?
The neurologist, 15(6), 369-71
Citation
Thaera, Greg M; Wellik, Kay E; Carter, Jonathan L; Demaerschalk, Bart M; Wingerchuk, Dean M. (2009). Do cannabinoids reduce multiple sclerosis-related spasticity?. The neurologist, 15(6), 369-71. https://doi.org/10.1097/NRL.0b013e3181bf5572
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