Researchers from the University of California, San Diego have released a new study linking positive effects of smoked marijuana to multiple sclerosis, giving sufferers of the disease hope for new, alternate forms of treatment.
Lead researcher Jody Corey-Bloom, M.D., Ph.D. set out to see if marijuana could have positive effects on spasticity, muscle tightness and pain that is a common symptom of multiple sclerosis.
Corey-Bloom and her fellow researchers at UCSD's Center for Medical Cannabis Research found that yes, positive effects exist, even if only qualitatively, and more research needs to be done in light of these findings.
The study appears today in the Canadian Medical Association Journal.
Results from the study, in their words:
Or, in English: researchers found that the 30 sufferers of multiple sclerosis had less perceived pain after using marijuana than the placebo.
Corey-Bloom and the researchers randomly issued both marijuana cigarettes and placebo cigarettes that looked and smelled like the real thing, but had been stripped of their delta-9-tetrahydrocannabinol (THC) to neutralize any psychoactivity. Participants smoked one cigarette per day for three days, under supervision. Eleven days later, participants were given whichever cigarette they did not receive in the first round, marijuana or placebo.
Researchers evaluated participants after each session. They found that participants who had marijuana cigarettes scored their spasticity and pain lower than they did before smoking.
"But researchers found that the people who smoked the cannabis had decreased cognitive functioning," reports the Huffington Post, "in that they scored lower on a test that measured their focus. This effect was only seen for a short term."
"It is difficult to completely blind participants to psychoactive substances," the study says. "Participants could generally tell which treatment they were receiving, although this is unlikely to affect objectively assessed spasticity scores."
The researchers also observed "acute cognitive effects" as a side effect of marijuana - in other words, participants were a bit slower than normal after marijuana use. "It is worth noting," the study says, "that conventional treatments such as baclofen and tizanidine hydrochloride may also affect cognition, although published data are scarce."
Nicholas LaRocca, vice president of healthcare delivery and policy research at the National MS Society, told Reuters Health that people with multiple sclerosis are already at risk for "cognitive changes," so potential for long-lasting effects of marijuana are a concern. This is consistent with another study last year that found risk of cognitive impairment in long-time marijuana users with multiple sclerosis.
"Research into cannabinoids and spasticity should continue," LaRocca told Reuters, "because medications may be able to harness the benefits of specific cannabis compounds, without the side effects linked to smoking pot."
"Larger, long-term studies are needed to confirm our findings and determine whether lower doses can result in beneficial effects with less cognitive impact," concluded Corey-Bloom.
You can read the complete study at the CMAJ.