Marijuana derivatives tested in mice.

A research study by an international group of investigators suggests that injections of chemical derivatives of marijuana--either natural or synthetic--may control spasticity and tremor in laboratory mice that have an MS-like disease called EAE. The study results were published in the March 2, 2000 issue of the journal Nature.

Spasticity (increased muscle tone causing stiff, painful movements) can sometimes be difficult to control even with approved medications. Tremor (involuntary trembling or quivering) is untreatable at present. Over the years there have been claims that marijuana--or its derivatives, known as cannabinoids--could help these MS symptoms, but clinical studies have been scanty and inconclusive.

Investigators at University College London and other institutions in Britain and the U.S. tested 5 different cannabinoids, and found that intravenous infusions of 4 of them could temporarily relieve spasticity and/or tremor in mice with EAE. But it's a long way from mice with EAE to humans with MS.

A clinical trial in the U.K.

A large clinical trial involving 660 people with different forms of MS is now under way in Britain to determine whether taking cannabinoids in capsule form can help control spasticity. Even if cannabinoids are shown to have a positive impact on these symptoms, it is unclear whether their psychoactive side effects can be minimized enough to make their regular use as a treatment feasible.

Pilot research in the U.S.

In the U.S., the National MS Society is supporting a pilot research project to investigate the impact of stimulating structures in the brain called cannabinoid receptors. The pilot study is in lab animals. This approach would avoid using marijuana derivatives altogether and might open new avenues to managing these difficult symptoms.