Past Coverage of 2016 CRA & AHPAPast Coverage of 2016 CRA & AHPA Return To RheumReports Home


Medical Marijuana for Chronic Pain - All Smoke and Mirrors?

February 18 2016 5:30 AM ET via RheumReports RheumReports

The endocannabinoid system is important for the maintainance of homeostasis. This endocannabinoid system moves us back from the sympathetic fight and fly system. Endocannabinoids reduce stress, and improve appetite, sleep, and pain. 

Two thirds of patients using marijuana in Canada today do so for chronic musculoskeletal pain. By 2024, it is estimated that 500,000 Canadians will be using medical marijuana. A meta-analysis for cannabinoid use for medical reasons  (JAMA 2015) uncovered 79 trials of which only 4 showed a low risk of bias. The studies of medical marijuana did show that symptoms were mostly improved with some improvement in pain. The Cochrane Collaboration summarized that there is a low quality of evidence for medical marijuana. A Canadian Rheumatology Association (CRA) mandated systemic review looked at 201 patients enrolled in 4 studies including 58 patients with rheumatoid arthritis, 71 with fibromyalgia, and 74 with osteoarthritis. In these studies, there was some statistically significant effect on pain.

The recent Compass Study (Pain 2015) concluded that quality controlled herbal cannabis appears to have a reasonable safety profile. This study included 431 patients randomized to 12 months of smoking 12.5% THC cannabis (n=215) versus control patients who took opioids (n=216). This study found no difference in the incidence of Serious Adverse Events (SAEs) between the two groups but non-SAEs were much greater in the cannabis group. SAEs are considered those that result in hospitalization or death. For context, the risk of SAEs with a biologic medication for rheumatoid arthritis is 5-6  per 100 pt-years. The risk of an SAE post abdominal aorta aneurysm surgery is about 10 per 100 pt-years. The risk of SAEs in cannabis users is a whopping 23 per 100 pt-years which was not statistically significantly different from opioid controls  with 27 SAE per 100 pt-years. Is this really a reasonable safety profile?  How could the editors of the journal accept the statement of a reasonable safety profile?

Patients are now beginning to extract 'the good stuff' from marijuana. The THC can be extracted with polar solvents such as butane. Vaping is like using an e-cigarette. The vape pens are portable, discrete and can be recharged it in your car. The vape pens contain propylene glycol which changes into formaldehyde which is 15 times more toxic than cigarette smoking.

A young healthy person’s brain shows changes in the nucleus accumbens and amygdala when using daily cannabis. Addiction occurs in 9% of all users. Driving is another issue with herbal cannabis as the acute psychomotor effects can last up to 5 hours. A meta-analysis showed a doubled risk of dying while driving and five times the risk of a motor vehicle accident in people with cannabis in their blood stream. From 2000-2012 the 'dead drivers' in Canada showed increasing blood levels of cannabis from 13 to 21%. 

What have we learned from Colorado and Washington states where cannabis is now legal? At the University of Washington about 22% of first-year students are current uses of canaibis. In some, the use of cannabis has now been normalized. 

Advocacy has outrun science, marijuana is not safe, and there are risks to patients and society. This is the classic epitome of smoke and mirrors.

Share This Report

About the Author

Dr. Andy Thompson
Dr. Andy Thompson

Dr. Andy Thompson is an Associate Professor at Western University and founder of,, and

View Full Bio

Trending Reports From 2016 CRA & AHPA