Nov. 6, 2003 -- The pain and muscle stiffness of multiple sclerosis may subside when patients take a pill containing the active ingredient found in marijuana, a new study shows. But spasticity may not improve, even though patients may think otherwise.
The study, conducted in Great Britain, looks at this connection -- a study triggered by numerous reports from patients who have had success. It appears in this week's issue of The Lancet.
"Our aim was to test that notion," writes lead researcher John Zajicek, PhD, with the University of Plymouth.
The available therapies for multiple sclerosis often are inadequate and can be limited by toxicity, he writes. Because of this, patients often experiment with alternative therapies, including cannabis, to ease their physical problems. While there is much anecdotal evidence that it works, very little scientific research has been done to back up the claims.
In Zajicek's study, 630 MS patients were given pills to take for 15 weeks: one group got THC (a major component of cannabis) in purified form, another got cannabis extract, and the third group got a placebo.
At the study's end, the patients in the THC and extract groups reported relief from subjective symptoms such as pain. Spasticity did not improve in these two groups even though many patients felt that it had, especially once their treatment was revealed to them. This may have explained their self-reported improvement, Zajicek says.
- Walking improved by 12% in the THC group, compared with 4% in the cannabis extract and placebo groups.
- 60% of patients in the cannabinoid treatment groups reported subjective improvements in spasticity, compared with 46% in the placebo group.
- 54% of patients given cannabinoids reported improvements in pain, compared with 37% in the placebo group.
The plant Cannabis sativa is complex and has more than 60 compounds. Most cannabinoid receptors in humans are present throughout the nervous system and immune system, which explains how the compounds affect certain multiple sclerosis symptoms, writes Zajicek.
Spasticity in multiple sclerosis is a complex phenomenon, he adds. Though spasms may not improve, cannabinoids might affect their perceptions of spasticity -- which itself could help control spasms.
His findings provide some evidence that cannabinoids could be useful in multiple sclerosis treatment, but more research is necessary, Zajicek writes.
SOURCE: Zajicek, J. The Lancet, Nov. 8, 2003: vol 263;pp 1517-1526. News release, The Lancet.