A small clinical trial by California investigators found some benefit of smoked marijuana against spasticity (muscle tightness and spasms) and pain in people with MS. Participants also experienced significantly reduced thinking ability after smoking marijuana, highlighting the need for research on cannabis products or other treatments that can more selectively reduce painful symptoms without producing adverse effects on cognitive function. Additional research examining the effects of marijuana on spasticity in MS is being supported by the National MS Society and others. The current study was published online on May 14, 2012 in the Canadian Medical Association Journal (CMAJ).
Background: For many people with MS, spasticity (muscle tightness and spasms) is a painful and disabling symptom that can have a significant negative effect on quality of life. Since the currently available medications do not entirely work for everyone, people with MS are searching for solutions to help with their spasticity. The search for more effective treatments for spasticity and other symptoms related to MS is an important research priority for the National MS Society.
The Society is currently supporting a clinical trial of different forms of cannabis products to test their ability to relieve spasticity in people with MS. This California-based trial is currently recruiting participants.
The study: Jody Corey-Bloom, MD, PhD (University of California, San Diego) and colleagues conducted a placebo-controlled clinical trial involving 37 people with MS whose spasticity was resistant to standard medications. In the first 3-day treatment phase, half of the participants smoked marijuana once a day, and half smoked a placebo, and all underwent testing. After waiting 11 days, the groups were switched so that those originally in the marijuana group were in the placebo group and those originally in the placebo group were in the marijuana group, and all tests were repeated. Thirty people completed this trial.
Compared to those on placebo, the investigators found significant improvement in spasticity according to a clinical measure called the modified Ashworth scale in those who smoked marijuana. They also reported improvement in patient-reported pain in those on marijuana. However, using a measure of information processing speed and accuracy called the Paced Auditory Serial Addition Test, the researchers found that after smoking marijuana, participants experienced significantly reduced thinking ability, compared to placebo. Limitations of this study include the small number of participants, the fact that many participants knew when they were smoking marijuana versus placebo, and that many participants had a history of marijuana use.
Comment: There is an unmet need for better ways to treat MS spasticity, which can have significant negative effect on quality of life. This study points to the potential of cannabis or cannabinoids for reducing spasticity and pain, but also highlights the need for more research to develop treatments that can selectively reduce spasticity without compromising cognition.
The search for more effective treatments for spasticity and other symptoms related to MS is an important research priority for the National MS Society, and the Society is currently supporting a clinical trial of different forms of cannabis products to test their ability to relieve spasticity in people with MS. The Society is also supporting research on non-pharmacologic treatments for spasticity, such as muscle-targeted exercise.