Cannabis capsules do not slow the progression of multiple sclerosis (MS), a large clinical trial has concluded. But while researchers were disappointed by the results, the findings could well be due to the fact that only one cannabinoid—tetrahydrocannabinol, or THC—was used in the capsules, rather than the complex symphony of at least 60 cannabinoids found in natural marijuana.
Particularly disappointing is the fact that the researchers failed to include cannabidiol (CBD) in the capsules, since it is one of the most medically promising cannabinoids found in marijuana. It’s especially heartbreaking that now, in the minds of many members of both the scientific community and the general public, “marijuana doesn’t work for MS” may become conventional wisdom due to a flawed study.
U.K. researchers at the Peninsula Medical School in Plymouth found that MS patients who were given capsules containing THC did not have better results than those given a placebo, reports Christine Hsu at Medical Daily
. The researchers had believed the capsules could provide effective therapy for patients in the disease’s secondary progressive stage, who have few treatment options.
|Lead researcher John Zajicek at the beginning of the study in 2003|
The study included 493 patients with progressive MS, and took eight years to complete. Participants took either THC or placebo capsules for three years.
In the clinical trial, which became known as CUPID (Cannabinoid Use in Progressive Inflammatory Brain Disease), MS patients were evaluated on both a disability scale administered by neurologists and another scale based on their own reporting.
“Overall the study found no evidence to support an effect of THC on MS progression in either of the main outcomes,” lead researcher John Zajicek wrote in the study, which was founded by Britain’s Medical Research Council.
But there was some evidence to suggest a beneficial effect in patients at the lower levels of disability at the start of the study. Additional studies that include more participants would be needed to confirm this, according to the researchers.
Many pharmaceutical companies have become more interested in medicinal uses of marijuana, especially as they realize the large potential profits, possibly through observing the emerging cottage medical marijuana industry in 17 states.
GW Pharmaceuticals, based in the U.K., has partnered with Bayer and Almirall to sell an under-the-tongue cannabis spray called Sativex to relieve spasticity, or muscle tightness related to MS. Crucially, none of the press reportage on the new Medical Research Council study seems to have noticed that even the Big Pharma product Sativex contains two cannabinoids—THC and CBD—and not just THC, which could explain its effectiveness for the MS patients who use it.
The study’s failure does not mean cannabis is no help to MS patients, said Professor David Nutt, former top government drugs advisor in the U.K.
“It would be wrong to interpret these preliminary findings to mean that cannabis does not achieve its licensed use,” Nutt said. “Cannabis is not licensed for limiting disease progression, it is licensed for dealing with spasticity and pain,” he told Reuters.
Multiple sclerosis is a disease in which the immune system destroys the myelin sheath which protects nerve cells in the brain and spinal cord. Secondary progressive MS involves a persistent accumulation of disease symptoms and disabilities.
Editor’s note: I have a very dear friend with MS whose symptoms are best relieved by cannabis.
Whether cannabinoids slow the progression of MS or not (and I believe if they had used whole-plant cannabinoids instead of just THC, they’d have gotten way different results), the fact remains that cannabinoids relieve the symptoms of the disease—patients tell us that, and we should listen.