“We observe significant improvement of symptoms of FM in patients using cannabis… knowledge of the endocannabinoid system and the role of the stress system in the pathopysiology of FM suggest a new approach to the suffering of these patients… results together with previous evidence seem to confirm the beneficial effects of cannabinoids on FM symptoms.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3080871/?tool=pubmed