Peripheral neuropathy, or neuropathy for short, is any condition or disease that damages or impairs peripheral nerves, or those located in the extremities, away from the spinal cord and brain. Neuropathy is caused by a wide variety of factors, including diabetes, chemotherapy, HIV, autoimmune conditions, and arthritis. Nerve damage from injuries or diseases such as cancer and multiple sclerosis (MS), for example, can lead to severe neuropathic pain.
Some studies and experts support the use of cannabidiol (CBD) to treat neuropathic pain.
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Research overview
Reuters reported on Feb. 6, 2019, that pain is by far the top reason why U.S. patients seek out medical cannabis. Word of mouth is a primary factor in people seeking cannabis medicine to soothe their pain, and there are ample studies to support these anecdotal reports. It is unclear whether CBD in the absence of other cannabinoids and terpenes can provide a remedy to neuropathy.
The studies
A 2012 literature review published in the Journal of Experimental Medicine examined at least one way that cannabinoids suppress inflammatory and neuropathic pain, by targeting alpha-3 glycine receptors. Citing the difficulty of treating neuropathic pain, the researchers also noted that CBD might be able to address the persistent discomfort associated with a range of diseases.
CBD may also relieve neuropathic pain by activating the brain's serotonin receptors. Neuropathic pain disrupts normal serotonin function, and a 2019 study in the journal Pain demonstrated the ability of CBD to relieve neuropathic pain in animals, due to CBD's ability to restore serotonin function. Authors of a similar study published in Brain Research concluded that the interaction of CBD with serotonin receptors could potentially be helpful for people with diabetic neuropathy.
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Neuropathic pain is a component of osteoarthritis. In an animal model of arthritis, researchers showed that when taken prophylactically, CBD can prevent the pain and nerve damage produced by arthritis. These results were published in 2017, also in the academic journal Pain.
When it comes to examining the role of CBD in neuropathic pain, human studies are few and far between. The most compelling evidence, however, comes from the study of a cannabis-derived pharmaceutical called Nabiximols, which contains equal parts CBD and THC. Clinical trials in the United Kingdom and Canada have demonstrated the ability of combined CBD/THC to relieve neuropathic pain.
Patient perspectives
Neuropathy is among the symptoms that lupus sufferers commonly experience. LupusCorner, a website for patients with the condition run by health-care technology developer Progentec Diagnostics, conducted an online survey in 2016 asking readers about cannabis use. Of the 781 respondents with lupus who reported using cannabis for various reasons, including as a treatment for their autoimmune disorder, 36% said they were using cannabis, either through smoking, topical application, or another method such as ingesting edibles.
Among patients who used cannabis as a direct strategy to manage their lupus symptoms, 83% said they would recommend it to another person with lupus. Yet 96% of respondents reported that their doctors had not talked with them about using cannabis to treat lupus, which indicates that most people are seeking out medical marijuana on their own.
Diana Whitney, a mother of two from Vermont, has been using medical marijuana and topical CBD to combat chronic pain. She now also uses it for anxiety and depression. In her 2018 article published in The Washington Post, Whitney wrote, “Applying the butter topically soothed my chronic pelvic pain and relieved symptoms of the debilitating bladder syndrome that had plagued me for a decade …”
What the experts say
Many medical experts are tentatively on board with cannabis as a viable treatment option for chronic pain and many see potential in CBD, though further research is needed. Dr. Bonni Goldstein, the medical director of Canna-Centers Wellness & Education in California and medical adviser to Weedmaps, stated in her article, “The Neuroprotective Properties of Cannabinoids,” that “if a person suffering from pain uses cannabis medicine, pain is often minimized or eliminated.”
Dr. Laszlo Mechtler, medical director of the Dent Neurologic Institute in Amherst, New York, served as senior researcher for a study of 204 adults ages 75 and older who took cannabis to ease various aches and pains. Seventy percent of the patients experienced pain relief, while one-third of the patients also reported reduced dependency on opioid painkillers.
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“Medical marijuana, in my opinion, is an excellent choice for patients with chronic disease, including chronic pain,” Mechtler said in a March 2019 interview with the Chicago Tribune.
In a 2018 article for Harvard Health Publishing, Dr. Peter Grinspoon, a Boston-based primary care physician and Harvard Medical School professor, discussed prior research on CBD for pain relief in conditions related to inflammation.
“CBD may offer an option for treating different types of chronic pain,” he wrote. “A study from the European Journal of Pain showed, using an animal model, CBD applied on the skin could help lower pain and inflammation due to arthritis.
“Another study demonstrated the mechanism by which CBD inhibits inflammatory and neuropathic pain, two of the most difficult types of chronic pain to treat. More study in humans is needed in this area to substantiate the claims of CBD proponents about pain control.”
Bottom line
Although randomized clinical trials in humans are necessary, preclinical evidence suggests a role for CBD in the treatment of neuropathic pain. Perhaps even more interesting is the potential of CBD oil as a preventative medication for nerve damage and associated pain.
Major contributions from Dr. Adie Rae.