Cannabis Extract and THC Both Significantly Reduced Urinary Incontinence in MS Patients
A substudy from the 630-patient CAMS trial found cannabis extract reduced urinary incontinence episodes by 38% and THC by 33%, both significantly better than placebo's 18% reduction, in MS patients.
Quick Facts
What This Study Found
This was a substudy of the large Cannabinoids in Multiple Sclerosis (CAMS) trial, which had randomized 630 MS patients across 33 UK centers to cannabis extract, THC, or placebo. Participants completed incontinence diaries.
All three groups showed significant reductions in urge incontinence episodes from baseline to end of treatment. However, both active treatments were significantly superior to placebo: cannabis extract reduced episodes by 38% (P = 0.005 vs. placebo), and THC reduced episodes by 33% (P = 0.039 vs. placebo), compared to placebo's 18% reduction.
Notably, this positive finding contrasted with the main CAMS study result, where no difference was seen in the primary outcome of spasticity (Ashworth scale). The authors suggested this indicated a genuine clinical effect of cannabis on bladder function in MS.
Key Numbers
630 patients in main CAMS study. Incontinence episode reduction: cannabis extract 38%, THC 33%, placebo 18%. Cannabis extract vs. placebo: P = 0.005. THC vs. placebo: P = 0.039.
How They Did This
Substudy of the multicenter CAMS RCT. From 630 MS patients randomized to oral cannabis extract, THC, or placebo across 33 UK centers. Participants completed incontinence diaries. Episode rates adjusted for baseline imbalance.
Why This Research Matters
Urinary incontinence is a common and debilitating MS symptom with limited treatment options. Finding significant benefits from both cannabis extract and THC in this large, rigorous trial setting provided stronger evidence than most previous studies, particularly since the main trial's primary outcome (spasticity) was negative.
The Bigger Picture
The finding that cannabinoids helped bladder symptoms more than spasticity in the same patient population suggests different MS symptoms may respond differently to cannabinoid treatment. Bladder function is regulated in part by cannabinoid receptors in the urinary tract, providing a biological rationale for this effect.
What This Study Doesn't Tell Us
This was a substudy, not the primary analysis. Not all 630 patients completed incontinence diaries. The adjustment for baseline imbalance was necessary but adds analytical complexity. The mechanism of cannabinoid effects on bladder function was not directly studied.
Questions This Raises
- ?Is the bladder effect sustained with long-term use?
- ?Could cannabinoids be developed specifically for neurogenic bladder dysfunction?
Trust & Context
- Key Stat:
- Cannabis extract reduced incontinence episodes by 38% vs. placebo's 18% (P = 0.005)
- Evidence Grade:
- Substudy from a large, well-designed multi-center RCT. Strong methodology but secondary analysis rather than the primary outcome of the parent trial.
- Study Age:
- Published in 2006. Cannabinoid effects on bladder function have been further studied since then, with some evidence supporting this finding.
- Original Title:
- The effect of cannabis on urge incontinence in patients with multiple sclerosis: a multicentre, randomised placebo-controlled trial (CAMS-LUTS).
- Published In:
- International urogynecology journal and pelvic floor dysfunction, 17(6), 636-41 (2006)
- Authors:
- Freeman, R M, Adekanmi, O, Waterfield, M R, Waterfield, A E, Wright, D, Zajicek, J
- Database ID:
- RTHC-00226
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Can cannabis help with MS bladder problems?
In this substudy of 630 MS patients, both cannabis extract and THC significantly reduced urinary incontinence episodes compared to placebo (38% and 33% reduction vs. 18%). This suggests a genuine clinical benefit for bladder symptoms.
Why did cannabis help bladder symptoms but not spasticity in this trial?
The main CAMS trial found no significant effect on spasticity (Ashworth scale), but this bladder substudy showed clear benefits. Different MS symptoms may respond differently to cannabinoids, possibly because different tissues have different cannabinoid receptor distributions and sensitivities.
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Cite This Study
https://rethinkthc.com/research/RTHC-00226APA
Freeman, R M; Adekanmi, O; Waterfield, M R; Waterfield, A E; Wright, D; Zajicek, J. (2006). The effect of cannabis on urge incontinence in patients with multiple sclerosis: a multicentre, randomised placebo-controlled trial (CAMS-LUTS).. International urogynecology journal and pelvic floor dysfunction, 17(6), 636-41.
MLA
Freeman, R M, et al. "The effect of cannabis on urge incontinence in patients with multiple sclerosis: a multicentre, randomised placebo-controlled trial (CAMS-LUTS).." International urogynecology journal and pelvic floor dysfunction, 2006.
RethinkTHC
RethinkTHC Research Database. "The effect of cannabis on urge incontinence in patients with..." RTHC-00226. Retrieved from https://rethinkthc.com/research/freeman-2006-the-effect-of-cannabis
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.