In Understanding CBD – Part 1, readers learned that cannabidiol, better known as CBD, is one of more than 113 special medicinal molecules produced by the cannabis herb called cannabinoids. Along with its infamous psychoactive sibling tetrahydrocannabinol (THC), products containing CBD (derived from either hemp or cannabis) are beginning to appear on store shelves throughout North America.

CBD offers a variety of health benefits to patients and consumers, including anti-anxiety efficacy and the power to reduce systemic inflammation—a root element of dozens of diseases, including arthritis, cancer, Crohn’s disease, and fibromyalgia. CBD has also been shown to reduce and sometimes eliminate seizures in adult epileptics and those suffering Dravet Syndrome (a serious childhood version of epilepsy that strikes during infancy). (It should be noted that many epileptic patients report greater efficacy, as measured by reductions in the number of seizures suffered, when consuming CBD combined with THC, as opposed to CBD alone.)

Recently, some prominent researchers and doctors with experience in cannabis medicine have gone counter to the popular perception that CBD is a fully non-psychoactive cannabinoid. While it is certainly considerably less psychoactive than THC, the latest science reveals a nuanced and complex manner in which CBD interacts with the human body and, more specifically, how it influences the effects of THC and other cannabinoids.

Given the powerful ability of this molecule to reduce anxiety and inflammation in humans and pets, what are the underpinnings of this mechanism so that patients might gain greater insight into its use and optimal efficacy?

Digging Deeper

Cannabinoids such as CBD and THC interact with the human body via a network of microscopic cellular receptors called the endocannabinoid system (ECS). The ECS extends beyond humans to all mammals—including common household pets like dogs, cats, and even hamsters—and is directly responsible for management of critical bodily systems such as mood, appetite, metabolism, sleep, and the ability to fight off infection and disease.

Only when a patient or cannabis consumer understands some of the underlying mechanisms within the mammalian ECS can they better comprehend the delicate relationship between “non-psychoactive” cannabinoids like CBD and their universal psychoactive sibling, THC.

Scientists have identified the specific manner in which CBD molecules bind, or “dock,” with cellular receptors. The ECS is comprised of two primary receptor types, CB1 and CB2. THC binds with CB1 receptors located throughout the brain and central nervous system. It was originally believed that CBD binds only with the CB2 receptors of the ECS found in the organs and tissues of the immune system.

Recent research has shown, however, that CBD does, in fact, bind with CB1 receptors. In a model involving a single docking site (binding receptor) per cell, THC and CBD molecules would obviously compete for binding preference at a particular CB1 receptor site. Scientists have learned, however, that an individual CB1 receptor on a cell features at least two docking sites, allowing a single receptor to accommodate two or more cannabinoid molecules.

When CBD molecules bind with a CB1 receptor, it is called “allosteric modulation,” something discovered only as recently as 2005. It wasn’t until 2015 that scientists leveraged this knowledge to uncover the fact that CBD “lowers the ceiling on the ability of THC and endogenous cannabinoids to stimulate CB1,” according to Project CBD. This results in CBD delivering a buffering effect to THC, decreasing the potency of the latter and assisting patients and consumers who may be prone to panic attacks or extreme anxiety (especially in certain sativa strains).

Allosteric molecules such as CBD work in tandem with sibling molecules such as THC that bind and modulate in a manner called orthosteric. Allosteric molecules like CBD are typically able to alter receptor modulation and, thus, patient efficacy, only when THC or another orthosteric cannabinoid is present at the binding site. According to Project CBD, “In terms of whole plant cannabis therapeutics, CBD’s efficacy as an allosteric modulator requires the co-presence of THC.”

The mere observation of the complex interaction between CBD and THC can be of great value to patients and adult users when attempting to predict and adjust the potency, psychoactivity, and other characteristics of their cannabis medicine.