To test whether cannabinoids reduce urge incontinence episodes without affecting voiding in patients with multiple sclerosis. This was part of the multicentre trial of the Cannabinoids in Multiple Sclerosis (CAMS) study.
The CAMS study randomised 630 patients to receive oral administration of cannabis extract, Delta(9)-tetrahydrocannabinol (THC) or matched placebo. For this substudy subjects completed incontinence diaries.
All three groups showed a significant reduction, p<0.01, in adjusted episode rate (i.e. correcting for baseline imbalance) from baseline to the end of treatment: cannabis extract, 38%; THC, 33%; and placebo, 18%. Both active treatments showed significant effects over placebo (cannabis extract, p=0.005; THC, p=0.039).
The findings are suggestive of a clinical effect of cannabis on incontinence episodes in patients with MS. This is in contrast to the negative finding of the CAMS study, where no difference was seen in the primary outcome of spasticity.