Smoked cannabis significantly reduced MS spasticity and pain in a placebo-controlled trial
In 30 MS patients, smoked cannabis reduced spasticity by 2.74 points more than placebo and pain by 5.28 points more, but also impaired cognitive performance.
Quick Facts
What This Study Found
Thirty MS patients with treatment-resistant spasticity completed a placebo-controlled crossover trial. Each participant smoked cannabis or identical placebo cigarettes once daily for three days, with an 11-day washout between periods.
Smoked cannabis reduced spasticity scores (modified Ashworth scale) by 2.74 points more than placebo (p<0.0001), a highly significant result. Pain scores on a visual analogue scale also improved by 5.28 points more than placebo (p=0.008).
However, cognitive performance on the Paced Auditory Serial Addition Test decreased by 8.67 points more with cannabis than placebo (p=0.003). Walking speed did not significantly differ. No serious adverse events occurred.
The authors concluded smoked cannabis was superior to placebo but recommended future studies examine whether different doses could provide benefits with less cognitive impact.
Key Numbers
30 completers out of 37 randomized. Spasticity reduction: 2.74 points better than placebo (p<0.0001). Pain reduction: 5.28 points better (p=0.008). Cognitive decline: 8.67 points worse (p=0.003). Timed walk: no significant difference (p=0.2).
How They Did This
Placebo-controlled, crossover trial. 37 randomized, 30 completed. Cannabis or identical placebo cigarettes smoked once daily for 3 days, with 11-day washout. Primary outcome: modified Ashworth scale. Secondary: VAS pain, timed walk, PASAT cognitive test.
Why This Research Matters
This was one of very few randomized trials of smoked cannabis (rather than oral or spray formulations) for MS spasticity. The strong effect on spasticity and pain, combined with the cognitive tradeoff, gave clinicians concrete data for shared decision-making.
The Bigger Picture
The cognitive impairment finding was clinically important. Patients and clinicians must weigh genuine spasticity and pain relief against cognitive costs. This tradeoff highlights why dose optimization and alternative delivery methods remain important research priorities.
What This Study Doesn't Tell Us
Small sample size (30 completers). Very short treatment period (3 days). The crossover design with 11-day washout may not have been long enough to eliminate carry-over effects. Blinding of smoked cannabis is inherently difficult despite identical-looking cigarettes.
Questions This Raises
- ?Could lower cannabis doses provide spasticity relief without cognitive impairment?
- ?Would longer-term use show tolerance to cognitive effects while maintaining spasticity benefits?
- ?How does smoked cannabis compare to Sativex spray for MS spasticity?
Trust & Context
- Key Stat:
- Spasticity reduction: 2.74 points better than placebo (p<0.0001)
- Evidence Grade:
- Randomized, placebo-controlled crossover trial. Strong design but small sample and very short treatment period. Blinding challenges inherent to smoked cannabis.
- Study Age:
- Published in 2012. This remains one of the few controlled trials of smoked cannabis for any medical condition.
- Original Title:
- Smoked cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled trial.
- Published In:
- CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 184(10), 1143-50 (2012)
- Authors:
- Corey-Bloom, Jody, Wolfson, Tanya, Gamst, Anthony(3), Jin, Shelia, Marcotte, Thomas D, Bentley, Heather, Gouaux, Ben
- Database ID:
- RTHC-00551
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Does smoked cannabis help MS spasticity?
In this trial, smoked cannabis significantly reduced spasticity and pain compared to placebo. The spasticity improvement was highly statistically significant (p<0.0001). However, it also impaired cognitive performance, creating a tradeoff that patients and doctors need to discuss.
Is smoking cannabis better than Sativex for MS?
This study did not directly compare them. Smoked cannabis showed large effects in this small trial, while Sativex spray showed more modest but consistent effects across larger trials. Smoking delivers THC faster, which may produce stronger effects but also more side effects.
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Cite This Study
https://rethinkthc.com/research/RTHC-00551APA
Corey-Bloom, Jody; Wolfson, Tanya; Gamst, Anthony; Jin, Shelia; Marcotte, Thomas D; Bentley, Heather; Gouaux, Ben. (2012). Smoked cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled trial.. CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 184(10), 1143-50. https://doi.org/10.1503/cmaj.110837
MLA
Corey-Bloom, Jody, et al. "Smoked cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled trial.." CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 2012. https://doi.org/10.1503/cmaj.110837
RethinkTHC
RethinkTHC Research Database. "Smoked cannabis for spasticity in multiple sclerosis: a rand..." RTHC-00551. Retrieved from https://rethinkthc.com/research/corey-bloom-2012-smoked-cannabis-for-spasticity
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.