The question of whether marijuana (Cannabis sativa) should be used for symptom management in MS is a complex one. It is generally agreed that better therapies are needed for distressing symptoms — including pain, tremor, and spasticity — that may not be sufficiently relieved by available treatments.

Some people with MS report that smoking marijuana relieves several of their MS symptoms. However, for any therapy to be recognized as an effective treatment, this kind of subjective, anecdotal reporting needs to be supported by carefully gathered objective evidence of safety and benefit. Unfortunately, it has proven difficult to do carefully controlled clinical trials of marijuana. One reason for this is that marijuana is psychoactive and makes people feel "high." This means that people taking the active drug during a clinical trial usually become aware of it — thus "unblinding" the study and possibly biasing results.

Investigators in the United Kingdom and United States tested the ability of two marijuana derivatives and three synthetic cannabinoids to control spasticity and tremor, symptoms of the MS-like disease, EAE, in mice. The results, published in the March 2, 2000 issue of Nature, suggested that four different cannabinoids could temporarily relieve spasticity and/or tremor. While the study suggested that similar derivatives of marijuana might be developed for human use, it was clear that the psychoactive effects of these cannabinoids would need to be reduced sufficiently to make them a safe and comfortable treatment for people with MS.