Medical Marijuana Effects in Movement Disorders, Focus on Huntington Disease; A Literature Review

Purpose: We aimed to comprehensively evaluate the effects of medical marijuana on symptoms that are relevant to movement disorders with a focus on Huntington disease (HD). Methods: A systematic review by literature search through PubMed and EBSCO electronic databases was conducted for relevant studies reported after 2002 on the effects of medical marijuana or cannabis use on tremor, spasm, spasticity, chorea, sleep quality and HD-specific rating scales. Study selection, quality assessment and data extraction was performed by three reviewers. Outcome measures were changes in psychomotor, and sleep related symptoms. The methodological quality of the included studies was evaluated. Results: A total of 22 studies were reviewed. There was strong evidence for significant improvement in the neurologic symptoms of spasms, tremors, spasticity, chorea, and quality of sleep following treatment with medical marijuana. Analysis of specific motor symptoms revealed significant improvement after treatment in tremors and rigidity. Furthermore, all pretreatment and post-treatment measures indicated a significant increase in average number of hours slept. Conclusion: Larger scale studies are warranted to test the benefits of medical marijuana in HD patients. In the meanwhile, clinicians may consider prescribing medical marijuana as part of their strategy for better symptomatic treatment of patients with HD.