Is there evidence for cannabis in fibromyalgia?

Fibromyalgia is characterized by central sensitization — amplified pain processing — and the ECS plays a key role in modulating central pain pathways, making it a theoretically strong indication. Clinical evidence is limited but growing. A 2019 Israeli observational study (n=367) found medical cannabis significantly reduced pain intensity (from 9/10 to 5/10 on NRS) and improved sleep and quality of life after 6 months. A 2020 RCT (van de Donk et al., n=20) found inhaled cannabis (both THC-dominant and CBD-dominant) reduced pain vs. placebo, with THC-dominant showing greatest effect. The fibromyalgia-ECS connection is supported by Ethan Russo's clinical endocannabinoid deficiency hypothesis — fibromyalgia patients show altered ECS tone. Limitations: most studies are observational; placebo-controlled trials are methodologically challenging; long-term data is absent.