Medical cannabis significantly reduced pain scores in fibromyalgia patients over six months | Research

The takeaway

In 367 fibromyalgia patients treated with medical cannabis for six months, pain intensity dropped from a median of 9 to 5 on a 10-point scale, with 81% achieving treatment response and mostly mild side effects.

Fibromyalgia patients, rheumatologists, and pain management clinicians.

Pain intensity dropped from 9.0 to 5.0 over six months

What the researchers found

Pain intensity decreased from median 9.0 to 5.0 (p < .001). Treatment response was achieved by 81.1% of patients. Age over 60 was associated with lower odds of response (OR 0.34). Prior cannabis experience predicted better outcomes (OR 2.46). Only 7.6% discontinued before six months. Most common adverse effects were mild: dizziness (7.9%), dry mouth (6.7%), GI symptoms (5.4%).

Why it matters

Fibromyalgia is notoriously difficult to treat. This is one of the larger prospective studies showing that medical cannabis can provide meaningful, sustained pain relief with an acceptable safety profile.

The numbers in context

367 patients. 82% female. Mean age 52.9. Pain: 9.0 to 5.0 (p < .001). 81.1% treatment response. 7.6% discontinued early. Dizziness 7.9%, dry mouth 6.7%, GI symptoms 5.4%.

How the study worked

Prospective observational study at a specialized medical cannabis clinic in Israel (2015-2017). 367 fibromyalgia patients followed for six months with questionnaire-based assessments. Response rate was 70.8%.

What this study cannot tell us

Observational study with no placebo control or blinding. Self-selected patient population at a cannabis clinic. 29.2% did not respond to the six-month follow-up, introducing potential bias.

How to read the evidence

Moderate: prospective observational study with reasonable size and follow-up, but no control group.

When this study was published

Published in 2019.

The bigger picture

Fibromyalgia patients often cycle through multiple medications with limited success. Medical cannabis may offer a viable option, though the lack of a control group means some of this improvement could be due to expectation effects.

Questions still open

How much of the improvement is due to placebo effect? Would the benefits persist beyond six months? Which cannabis formulations and dosages work best for fibromyalgia?

Common questions

Is medical cannabis approved for fibromyalgia?

In Israel, where this study was conducted, medical cannabis can be prescribed for fibromyalgia. Approval varies by country and state.

Why did older patients respond less well?

The study found that age over 60 was associated with lower treatment response (OR 0.34). The reasons are unclear but could include differences in cannabinoid metabolism, tolerance development, or different pain mechanisms in older patients.

Read the original research

Safety and Efficacy of Medical Cannabis in Fibromyalgia.

Journal of clinical medicine, 8(6)

View on PubMed ↗Publisher’s paper ↗

Citation

Sagy, Iftach; Bar-Lev Schleider, Lihi; Abu-Shakra, Mahmoud; Novack, Victor. (2019). Safety and Efficacy of Medical Cannabis in Fibromyalgia.. Journal of clinical medicine, 8(6). https://doi.org/10.3390/jcm8060807