CBD and Chronic Pain
by Sara Jane Ward, Ph.D. and Ronald Tuma, Ph.D. (Lewis Katz School of Medicine at Temple University)
The pain-alleviating properties of the chemical constituents of the Cannabis sativa plant have been appreciated since ancient times. Presently, over 30 states have legalized medical marijuana legislation in place or in development, and the most common indication patients cite for seeking medical marijuana treatment is for the alleviation of chronic pain. The number of legal medical marijuana users is predicted to exceed 2.5 million in the coming years. The therapeutic potential of Cannabis has for several decades been directly linked to delta-9-THC, typically the most abundant phytocannabinoid in the plant. THC acts on proteins in the body called cannabinoid CB1 and CB2 receptors. Action on the CB1 receptors can produce pain-alleviation effects, but also other effects on the central nervous system that may be unwanted by patients, such as euphoria, deficits in attention, sedation, and risk of physical dependence. But THC isn’t the only phytocannabinoid in the plant that possesses strong therapeutic potential. Cannabidiol is typically the second most abundant phytocannabinoid in Cannabis, and some medical marijuana strains are currently being cultivated to contain much higher percentages of cannabidiol and very low concentrations of THC to optimize therapeutic effects while lessening potential adverse effects. Cannabidiol was actually isolated from Cannabis prior to the discovery of THC, and the therapeutic potential of cannabidiol has been investigated for decades.
The majority of what we know about the therapeutic potential of cannabidiol has been ascertained from animal model studies of a range of disorders and diseases, including chronic inflammatory and neuropathic pain and other insults to the central nervous system. For example, our laboratory was the first to demonstrate that CBD prevents the development of touch and temperature sensitivity in mouse models of chemotherapy-induced peripheral neuropathy and spinal cord injury. We have also demonstrated that treatment with CBD decreases damage following stroke in a mouse model of cerebral ischemia. In addition, cannabidiol possesses anxiety-decreasing as well as anti-psychotic effects in animal studies. Taken together, these results support the idea that cannabidiol may possess exciting therapeutic potential for a range of conditions while producing fewer unwanted side effects as compared to THC or whole cannabis. However, it is obvious that although the data from animal studies are compelling, safety and efficacy of CBD formulations must be demonstrated in humans as well.
CBD is currently being studied in over 100 clinical trials worldwide; many of these clinical trials are testing the safety and efficacy of CBD in combination with THC, but several are examining the effects of CBD alone. Conditions under investigation range from general physiological effects in healthy individuals to alleviation of Crohn’s disease, from childhood epilepsy to alcohol use disorder. Published findings include results showing that CBD can reduce schizophrenic-like symptoms and social anxiety in patients. Most other clinical results are still pending.
As scientists, we believe in evidence-based medical practices. We are encouraged by the confluence of animal and human safety and efficacy data but recognize that there are several unanswered questions regarding optimal doses, best routes of administration, whether CBD is more effective alone or in combination with other components of the plant, and whether and how CBD interacts with other medications. And as scientists, we will strive to continue to do our jobs to provide you with this information.