A study published in The British Journal of Pharmacology in 2009 looked at the mechanism of action for cannabidiol (CBD), which the authors admitted was not fully understood. After running several tests on rodents using varying amounts of CBD, the researchers found that the cannabinoid reduced acute stress response and delayed emotional consequences. Looking at the data and other studies, the researchers suggested two possible mechanism for the anxiolytic effects, which were as follows:
CBD increases endocannabinoid levels by blocking the reabsorption of the body’s natural cannabinoids and the enzymes that metabolize them
CBD activates 5-HT1A serotonin receptors in the brain that affect blood pressure, heart rate and mood levels
As a binding site for serotonin, the 5-HT1A receptor is typically associated with depression, and its role in anxiety is still debated. However, numerous studies suggest that activating the receptor can protect against stressful emotional change, reduce anxiety-like behavior and improve coping abilities. The receptor is heavily clustered in areas of the brain associated with mood, and a person who lacks receptors and/or sensitivity could have issues with anxiety and depression. Neurotransmission problems (e.g., neurotransmitters failing to reach or activate receptors) can also play a role in anxiety disorders. When CBD molecules bind to 5-HT1A, they activate inhibitory serotonergic effects that slow signaling and promote homeostasis within the body. CBD also activates the TRPV1 (pain, inflammation, body temperature) and adenosine A2A (cardiovascular, respiratory) receptors, the latter of which appears to aid in anxiety management.