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The two different sub-types of multiple sclerosis
Multiple sclerosis is an auto-immune neurodegenerative disease affecting primarily people in their young age. It has been classified into two subtypes:
- Relapsing-remitting multiple sclerosis: This type of multiple sclerosis is seen in 80% of MS patients. The patient experiences an acute attack of symptoms which may consist of impaired vision, muscular spasm, difficulty in balancing and extreme fatigue. The attack may subside after a few weeks or months and then recur. Experts believe that these episodes are seen in the early course of the disease and later around 50% of the patients develop the second subset of MS called as the progressive MS.
- Progressive multiple sclerosis: It is believed that within 10 years of the onset of the disease, 50% of cases progress to this type of MS. While the acute episodes of MS in the relapsing-remitting type of MS can be contained with the help of medicines, there are no medicines available to cure the symptoms of progressive type of MS.
The researchers taking part in the Cannabinoid Use in Progressive Inflammatory Brain Disease (CUPID) study have found that tetrahydrocannabinol (THC), the active ingredient of marijuana has no role to play in altering the course of progressive MS. The study is being carried out by the University of Plymouth, under the leadership of Dr. John Zajicek, a clinical neuroscientist at Plymouth University Peninsula Schools of Medicine and Dentistry.
Early results obtained in the CUPID study had shown the beneficial effects of marijuana on multiple sclerosis
Initial results obtained in the same study in 2003 had found that THC may slow down the progression of MS and had raised the hopes of the many patients suffering from MS around the world. Enthused by the initial reports, the researchers conducted an extended three years follow up study to find the effect of medical marijuana on the progression of multiple sclerosis.
Zajicek and his colleagues had initially included 630 patients suffering from advanced stage multiple sclerosis in the CUPID study. The patients were randomly divided and were given either marijuana containing cannabinoid compounds or placebo for a duration of 15 months.
The patients who received marijuana also complained of less pain compared to the patients who received the placebo.
Read More: Therapeutic Uses Of Medical Marijuana
Medical marijuana is of little help in slowing the progression of progressive multiple sclerosis
For the extended follow up study, patients between the ages of 18 and 65 years of age suffering from primary or secondary progressive multiple sclerosis were recruited. 498 patients were given marijuana (dronabinol) while 329 were put on placebo. The maximum dose of marijuana was 28 mg per day.
The researchers found that even though the medical use of marijuana may provide some relief from symptoms to patients at the lower end of the disability scale, it has no effect on the long term progression of the disease. The benefits reported in the earlier study were due to the effect marijuana has on the mood of the patient. Due to his elevated mood, he becomes less sensitive to the muscle spasm even though the spasm continues to persist. The relief from pain is also associated to an elevated mood.
The results of the present study have been published in the journal Lancet Neurology.