Regis Vaillancourt, BPharm, PharmD,Bhumi Bhojak, MD, BSc,Sherine Sterling


August 17, 2023


To observe the effect of cannabis on fibromyalgia illness severity and related symptoms of depression and anxiety.
A retrospective chart review was conducted to identify all patients who indicated fibromyalgia as a primary reason for seeking medical cannabis and completed at least 1 follow-up visit at Harvest Medicine clinics from January 2017 to July 2021. Data extracted from patient charts included Patient Health Questionnaire-9 (PHQ-9) scores, Generalized Anxiety Disorder-7 (GAD-7) scores, and self-reported illness severity scores. Changes in these scores between a patient’s intake and first follow-up visits were calculated and analyzed for significance overall and in different demographic subgroups. Patients for whom no follow-up data were available were excluded.
Significant reductions were observed in overall mean PHQ-9 score (10.6 ± 6.6 vs 8.0 ± 6.0, P<0.001; n = 446) between intake and first follow-up; this reduction was clinically significant in 27% of patients. Overall mean GAD-7 score was also significantly reduced (8.0 ± 6.1 vs 5.9 ± 5.4, P<0.001; n = 593), with clinically significant reduction seen in 22% of patients. Overall mean self-reported illness severity was likewise significantly reduced (4.1 ± 0.7 vs 2.9 ± 1.0, P<0.001; n = 805), with 75% of patients reporting a reduction from their intake severity rating.
These data show that medical cannabis may play an important role in the management of fibromyalgia and associated symptoms of depression and anxiety. Further studies are needed to support the use of medical cannabis in patients with fibromyalgia.


Vaillancourt, R., Bhojak, B., Sterling, S., Cameron, J. D., & Chan, C. Self-Reported Effects of Medical Cannabis on Illness Severity, Depression and Anxiety in Fibromyalgia Patients: A Large Retrospective Case Series.