Cannabinoids for the Treatment of Movement Disorders.

OPINION STATEMENT: Use of cannabinoids as medications has a long history. Unfortunately, the prohibition of cannabis and its classification in 1970 as a schedule 1 drug has been a major obstacle in studying these agents in a systematic, controlled manner. The number of class 1 studies (randomized, double-blind, placebo-controlled) in patients with movement disorders is limited. Hence, it is not possible to make recommendations on the use of these cannabinoids as primary treatments for any of the movement disorders at this time. Fortunately, there is an expanding body of research in animal models of age-dependent and disease-related changes in the endocannabinoid system that is providing new targets for drug development. Moreover, there is growing evidence of a "cannabinoid entourage effect" in which a combination of cannabinoids derived from the plant are more effective than any single cannabinoid for a number of conditions. Cannabis preparations may presently offer an option for compassionate use in severe neurologic diseases, but at this point, only when standard-of-care therapy is ineffective. As more high-quality clinical data are gathered, the therapeutic application of cannabinoids will expand.