Frontiers in Pharmacology in April 2018 reviewed several publications on the mechanism of migraines as it relates to the effectiveness and safety of cannabinoid migraine treatment. The occurrence of a migraine is multifaceted. However, it is believed that the initiation of a migraine is caused by lowering the nociceptive signal processing in response to release of pro-inflammatory agents.
Endocannabinoid system (ECS) is a comprehensive signaling system present in virtually every cell type and plays a critical role in maintaining body homoeostasis. It functions to reduce pain and to alleviate neurodegenerative and inflammatory damage. The ECS signals are relayed by two primary types of receptors: Type 1 cannabinoid receptor (CB1) and type 2 cannabinoid receptor (CB2).
The most abundant cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD) function at the level of these receptors (CB1 and CB2) which correct the improper anti-inflammatory effect of cytokine production. The abundance of CB1 receptors in the brain and CB2 receptors in the immune tissue/peripheral nervous system makes them an attractive target for migraine treatment by reducing enhanced cortical excitability and inflammation, respectively. This suggests that the anti-inflammatory potential of cannabinoids represent a promising target and therapy to counteract migraine.
CBD does not have the intoxicating and psychoactive effects linked with CB1 receptor activation as caused from THC use. Since CBD is non-psychotropic and has a better side effect profile than THC, CBD therapy is the best initial choice for migraine prevention/treatment from a cannabinoid therapy standpoint. Full spectrum CBD products which contain very small amounts of THC (less than 0.3% THC) are the most appropriate choice of CBD in this setting if the patient is not concerned of THC drug testing.