Cannabis and Neurogenic Pain – Is It Really So Effective?

The folklore that THC derived from cannabis plants in its crude, or as its proponents are fond of saying, “natural,” state is a viable and highly effective treatment for a number of serious medical conditions is just that – folklore, as far as the FDA is concerned. It is easier to say cannabis has medicinal value, but it is very difficult to prove. The same, of course, applies to other possible treatments or medicines. Cannabis has never undergone the scrutiny of rigorous, prospective, random assignment, double blind, placebo controlled investigation, as is commonly applied to all FDA approved drugs before they are declared safe, effective and ready to be unleashed on the public. Cannabis has been touted, via anecdotes and user medicine reports, as a proven treatment of chronic pain by media, users and by some pain physicians and other health practitioners. Yet its efficacy has never been tested by rigorous research.

What Does the Best Available Science Tell Us about Cannabis?

To assess the benefits and risks of plant-based cannabis preparations for treating chronic pain in adults, Nugent, et al (2017) conducted a meta-analysis of the Cochrane Database of Systematic Reviews (the gold standard of meta-analysis) and several other databases from inception to March 2017. The study selection was limited to trials and observational studies involving adults using phytocannabinoid preparations who reported chronic pain, poor quality of life and adverse effect outcomes. After assessing the characteristics, methods and study quality, investigators graded the overall strength of evidence using standard data synthesis criteria from 27 trials, meeting the study’s quality parameters.

The results showed “low-strength of evidence” regarding the effectiveness of cannabis as a treatment for neuropathic pain. The efficacy among patients with other forms of chronic pain was not found or proven in the meta-analysis. In addition, 11 systematic reviews plus more than 30 primary studies revealed numerous harmful effects from cannabis among the treatment participants, including short-term cognitive impairment, psychotic symptoms and increased risk for motor vehicle accidents.

Why Does This Matter?

Everyone would like to find safer and non-addicting treatments for pain. Cannabis may not be the answer. In the best study to date, the scant evidence, based upon poor quality research, suggests that cannabis may alleviate neuropathic pain in some patients but is not effective for other types of chronic pain. In addition, the evidence that cannabis is associated with an increased risk for adverse psychiatric events, mental illness and motor vehicle accidents is both strong and alarming considering current claims of its safety and efficacy.

Nearly all the research lacked rigorous scientific controls. However, the cannabis studied may not reflect the commercially available products; and the findings showed limited applicability to older and chronically ill populations. These confounding variants were not accounted for in the studies. Moreover, we now know that cannabidiol (CBD), a constituent of phytocannabinoid, has numerous therapeutic benefits. This is a critical confounding variable was not accounted for. I’d guess that a constituent of the cannabis plant, likely some type of cannabinoid, will be studied and found to be safe and effective for pain or other treatments. At this point in time, it is hard to be that optimistic. How can one know if the results were from THC, CBD or something else in crude cannabis? This meta-analysis tells us to slow down and conduct our due scientific diligence using prospective, random assignment, double blind studies. Until then, and only then, will we know the benefits and risks.