A study conducted by a team of researchers at Oregon Health and Science University (OHSU) suggests that cannabis products do provide relief against chronic pain, but only on a short-term basis and they also have multiple side effects.

Cannabis products that promise relief from chronic pain have been legalized and are being sold in various parts of the US and several other countries. However, these marijuana-based medicines and their effect on the human body have not been researched in detail. Explaining why this matters, the lead author of the study and emeritus professor from OSHU School of Medicine, Marian S. McDonagh writes:

“With so much buzz around cannabis-related products, and the easy availability of recreational and medical marijuana in many states, consumers and patients might assume there would be more evidence about the benefits and side effects. Unfortunately, there is very little scientifically valid research into most of these products.” 

The study, which is also supported by the American College of Physicians, reviewed the findings from 25 scientific trials, 18 randomized controlled experiments, and seven observational studies conducted on more than 13,000 subjects — making it one of the largest on the topic of cannabis and pain relief.

How effective cannabis products are against chronic pain?

During their study, the researchers examined the effect of two FDA-approved synthetic cannabis drugs (nabilone and dronabinol) and a cannabis-derived medicinal spray (nabiximols spray). We’re not talking about smoking weed here.

The human body has an endocannabinoid system (ECS), a system that influences a person’s ability to sense pain, in addition to regulating several other functions such as eating behavior, temperature, immune system activity, sleep, etc. Based on the THC-CBD ratio, cannabis products mimic the function of ECS to deal with chronic pain.

The study notes that the pain relief properties in cannabis products depend on the THC-CBD (tetrahydrocannabinol-cannabidiol) ratio, and the concentration of these two cannabinoids is also linked to the different side effects resulting from the use of cannabis medicines.  

While the drugs only contain THC, the spray had both THC and CBD in equal proportions. All the cannabis products did deliver short-term relief and some benefits against neuropathic pain (a condition caused due to injury of nerves that transmit information between the spinal cord, muscles, brain, and different other body parts). However, the researchers found that the products also caused side effects such as dizziness, nausea, and sedation.

The analysis of different synthetic products revealed that cannabis medicines with comparable THC to CBD ratios proved to be helpful in chronic pain treatment. However, the products having high THC to CBD ratios either delivered moderate or no clinical benefits — but still triggered multiple side effects. Also, due to the limited availability of studies and data concerning cannabis products, the researchers couldn’t examine the effect of many cannabis product types. 

“For some cannabis products, such as whole-plant products, the data are sparse with imprecise estimates of effect and studies had methodological limitations,” the researcher notes.

We still don’t know enough about cannabis products

About 1.5 billion people are facing chronic pain-related issues across the globe. It is estimated that there are 100 million chronic pain patients in the US alone. The current unhealthy lifestyle also increases the risk of chronic pain in adults with increasing age. To deal with the problem, many patients start taking cannabis products without understanding the real impact these products have on their bodily functions.

Cannabis products are derived from different types of sources such as flowers, dried extract, synthetic materials, and whole plants. Although it is true that THC and CBD have pain-relieving properties, not all cannabis products have the same effectiveness.

“Cannabis products vary quite a bit in terms of their chemical composition, and this could have important effects in terms of benefits and harm to patients. That makes it tough for patients and clinicians since the evidence for one cannabis-based product may not be the same for another.” writes Roger Chou, co-author of the study and director of OHSU’s Pacific Northwest Evidence-based Practice Center.

Since little research has been done on these products, the researchers recommend that if a patient is looking forward to using cannabis products for treating chronic pain, the best approach is to first consult a physician. To bring out the evidence related to the health effects of cannabis products, the researchers are currently working on a project called Systematically Testing the Evidence on Marijuana (STEM). Given the popularity of such products, more research in the field is definitely required.

The study is published in the journal Annals of Internal Medicine.