Fibromyalgia has been considered as a clinical endocannabinoid deficiency (CECD). This would mean that fibromyalgia  would be a disease related to the endocannabinoid system and it could be treated with cannabinoids (Russo, 2004, 2008, 2016).

A recent review of the effects of cannabinoids in fibromyalgia concluded that synthetic cannabinoid based drug Nabilone can be effective to treat symptoms of fibromialgya (Walitt, Klose, Fitzcharles, Phillips, & Häuser, 2016).

In another review, Lynch and Campbell (2011) also concluded that cannabinoids can be useful to treat fibromyalgia-related pain.

However, other review concluded that there is not enough evidence to say that cannabinoids can help to treat any fibromyalgia related symptom (Fitzcharles, Baerwald, Ablin, & Häuser, 2016).

Fiz, Durán, Capellà, Carbonell and Farré (2011) compared the subjective perception of the fibromyalgia symptoms between 28 cannabis users and 28 non-cannabis users. Results showed a reduction of pain and stiffness and increased relaxation, somnolence and feeling of well being. However, there were no differences in other variables related to quality of life.

Patients using herbal cannabis to treat fibromyalgia showed also negative psychosocial parameters which were not present in other patients using prescription cannabinoids (Ste-Marie, Fitzcharles, Gamsa, Ware, & Shir, 2012).

A sub-population of patients with fibromyalgia showed lower pain perception after daily administration of THC (2.5 to 15mg). Authors suggested these effects are due to the analgesic action of THC in the central nervous system (Schley et al., 2006)

The use of the synthetic cannabinoid-based drug Nabilone showed improvement in pain reduction and life quality in patients with fibromyalgia (Skrabek, Galimova, Ethans, & Perry, 2008).

References

Fitzcharles, M.-A., Baerwald, C., Ablin, J., & Häuser, W. (2016). Efficacy, tolerability and safety of cannabinoids in chronic pain associated with rheumatic diseases (fibromyalgia syndrome, back pain, osteoarthritis, rheumatoid arthritis): A systematic review of randomized controlled trials. Schmerz (Berlin, Germany), 30(1), 47-61. https://doi.org/10.1007/s00482-015-0084-3

Fiz, J., Durán, M., Capellà, D., Carbonell, J., & Farré, M. (2011). Cannabis use in patients with fibromyalgia: effect on symptoms relief and health-related quality of life. PloS One, 6(4), e18440. https://doi.org/10.1371/journal.pone.0018440

Lynch, M. E., & Campbell, F. (2011). cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials. British Journal of Clinical Pharmacology, 72(5), 735-744. https://doi.org/10.1111/j.1365-2125.2011.03970.x

Russo, E. B. (2004). Clinical endocannabinoid deficiency (CECD): can this concept explain therapeutic benefits of cannabis in Migraine, fibromyalgia, irritable bowel syndrome and other treatment-resistant conditions? Neuro Endocrinology Letters, 25(1-2), 31-39.

Russo, E. B. (2008). Clinical endocannabinoid deficiency (CECD): can this concept explain therapeutic benefits of cannabis in Migraine, fibromyalgia, irritable bowel syndrome and other treatment-resistant conditions? Neuro Endocrinology Letters, 29(2), 192-200.

Russo, E. B. (2016). Clinical endocannabinoid Deficiency Reconsidered: Current Research Supports the Theory in Migraine, Fibromyalgia, Irritable Bowel, and Other Treatment-Resistant Syndromes. Cannabis and cannabinoid Research, 1(1), 154-165. https://doi.org/10.1089/can.2016.0009

Schley, M., Legler, A., Skopp, G., Schmelz, M., Konrad, C., & Rukwied, R. (2006). Delta-9-THC based monotherapy in fibromyalgia patients on experimentally induced pain, axon reflex flare, and pain relief. Current Medical Research and Opinion, 22(7), 1269-1276. https://doi.org/10.1185/030079906X112651

Skrabek, R. Q., Galimova, L., Ethans, K., & Perry, D. (2008). Nabilone for the treatment of pain in fibromyalgia. The Journal of pain: Official Journal of the American pain Society, 9(2), 164-173. https://doi.org/10.1016/j.jpain.2007.09.002

Ste-Marie, P. A., Fitzcharles, M.-A., Gamsa, A., Ware, M. A., & Shir, Y. (2012). Association of herbal cannabis use with negative psychosocial parameters in patients with fibromyalgia. arthritis Care & Research, 64(8), 1202-1208. https://doi.org/10.1002/acr.21732

Walitt, B., Klose, P., Fitzcharles, M.-A., Phillips, T., & Häuser, W. (2016). cannabinoids for fibromyalgia. The Cochrane Database of Systematic Reviews, 7, CD011694. https://doi.org/10.1002/14651858.CD011694.pub2