Cannabis truly helps people with multiple sclerosis 30 March 2006
Cannabis may loosen the stiff and spastic muscles of people with multiple sclerosis, and not just their minds, a follow-up study has found.
The results contradict findings from the first phase of the study, where improvements seemed to be largely due to "good moods".
“There does seem to be evidence of some benefit from cannabis in the longer term that we didn’t anticipate in the short term study,” says John Zajicek, at Peninsula Medical School in Exeter, UK, and one of the research team.
In 2003, Zajicek and his colleagues published results on the largest study to date of cannabinoids and MS. The trial included 630 advanced-stage MS patients who took either cannabinoid compounds or a placebo for 15 weeks.
Compared with those on placebos, patients who received active compounds said they both felt less pain and less muscle spasticity – the spasms characteristic of this neurodegenerative disease.
But physiotherapists using standard evaluations were unable to corroborate the patients' claims of improved mobility or muscle stiffness.
The results were further complicated because about two thirds of the patients who received cannabis compounds, such as D9-tetrahydrocannabinol (THC), guessed they had not received a placebo, due to the drugs effect on their mind.
The knowledge that they were receiving an active compound, along with the mood-altering effects of THC, may have explained why subjects reported improvements.
“If you’ve got a drug that elevates mood and makes people feel better, how can you be sure that it’s really affecting their underlying disease and their symptoms?” asks Zajicek.
When the short-term study ended, however, the researchers gave all subjects the opportunity to continue their treatment for a full year. The team wanted to extend the study to gather information on the safety of long-term cannabinoid use.
More than 500 patients agreed to stay on their original treatment. One group took pills of D9-tetrahydrocannabinol (THC), the active ingredient in cannabis. The second group received natural cannabis extract, and the third group took a placebo.
At the end of the 12 month period, the patients were evaluated again using the same measures as in the first study. But this time, physiotherapists saw a marked improvement for subjects on active drugs. They had reduced muscle spasticity and an improved overall score for their level of disability.
Zajicek is cautious about the implications of the study as it was not specifically designed to test the efficacy of drugs over 12 months. But the results do support animal research that shows cannabinoids may slow nerve cell death and protect against damage.
The findings were presented at the British Association for the Advancement of Science Festival, in Exeter, UK.
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