On Monday The American Academy of Neurology released the results of a survey of 32 different studies. The studies, altogether involving 2,000 patients, looked at the effects medical marijuana has had when treating neurological diseases such as multiple sclerosis, Parkinson’s disease and epilepsy.
Through the review of these studies, researchers have been able to identify that marijuana does have positive effects on some of the symptoms of MS, but that the drug isn’t effective in treating symptoms of Parkinson’s.
For patients with MS who take cannabis either as a pill or as an oral spray, the drug relieves spacity, pain related to spasms or pain related to MS lesions. However, the review concluded that MS patients who experienced tremors do not experience relief from that symptom when taking medical marijuana. Similarly, people with late-stage Parkinson’s didn’t experience any relief from involuntary movements that were abnormal.
There was not enough evidence for researchers to recommend marijuana for treating symptoms for epilepsy. Other symptoms that didn’t have enough evidence behind them were Tourette’s syndrome tics, motor symptoms in Huntington’s disease or abnormal neck movements.
In only two studies did participants actually smoke marijuana, but there wasn’t enough evidence to conclude whether that method was effective in treating symptoms.
Following the publication of the results of the review, the chief of neurology at New York Medical college and also one of the authors of the review, Barbara Koppel, stated that she hopes more studies will come out of the results of the review.
Another issue to be addressed in future studies—along with more information about the effects of marijuana on more neurological diseases—is how marijuana can affect already-existing depression in patients with neurological diseases. Koppel stated that though there was link between marijuana and depression in the studies, it is something for physicians to be aware of.