Smoking marijuana may reduce certain symptoms in patients with multiple sclerosis, according to a new small study published Monday in the Canadian Medical Association Journal.
Researchers from the University of California at San Diego School of Medicine conducted a double blind, controlled clinical trial that included 30 participants who had multiple sclerosis. The scientists hoped to understand whether smoked cannabis reduces symptoms of spasticity, a common symptom of the disease that refers to stiffness and involuntary muscle spasms.
While most past trials have focused on the effects of a pill-form of cannabis, researchers wanted to see specifically whether a smoked form of the drug has a beneficial effect.
"Smoking cannabis was indeed superior to the placebo in reducing spasticity and pain, but that certainly came at a price," said Dr. Judy Corey-Bloom, director of the Multiple Sclerosis Center at UC San Diego and lead author of the study.
Patients experienced less pain after smoking, but also experienced fatigue, impairment of cognitive function, attention and concentration.
"There can be a lot of sources of pain with MS, from that pins and needles and burning feeling, but also the pain from muscle stiffness," said Corey-Bloom. "It's important for patients to know that pain can be treatable."
Multiple sclerosis is an autoimmune disease that affects the brain and spinal cord. The disease attacks the myelin sheath, a protective covering that surrounds nerve cells, and approximately 400,000 Americans have MS, according to the National MS Society. About 200 people are newly diagnosed each week. The disease is degenerative, and symptoms, which affect the muscles, bowel function, vision, numbness, sexual function and personality, can vary and range in severity.
"The effect of the drop in spasticity [in the study] is real and important," Dr. John Corboy, professor of neurology at University of Colorado School of Medicine, wrote in an email. "So, problem is, who can use this, as marijuana makes 100 percent of people stoned at the dose needed to produce the effect. Authors allude to this in the last part of the abstract (i.e. can you find a dose that works but doesn't impair you?). My answer is, I doubt it."
The trick would be to identify and isolate the key cannabinoids in the marijuana that show benefits and find a way to concentrate and deliver them, said Nicholas LaRocca, vice president of healthcare delivery and policy research at the National Multiple Sclerosis Society. "This would solve the problem without creating other problems."
Researchers examined physical performance (using a timed walk), cognitive function and measured pain levels in the patients by using a modified Ashford scale. The scale grades the intensity of muscle tone by measuring resistant of range of motion and rigidity.
"Patients saw an average of about a 30 percent pain reduction after smoking the cannabis," said Corey-Bloom.
But it's important to note that several patients in the study had a history of marijuana use, which could "create a bias in the sample," said LaRocca.
Nevertheless, LaRocca said the researchers did a thorough job in conducting the study and "the bottom line is that further investigation of cannabis is warranted in considering its possible usefulness for spasticity in MS."