Recent scientific studies suggest cannabis's active molecules (called "cannabinoids") can reduce the symptoms of migraine headaches. Cannabinoids act in multiple ways to block pain, reduce inflammation, and provide effective relief from migraine headaches.
Migraines are complex biological events, making them difficult to treat. Multiple events such as stress, hormonal changes, and alcohol can trigger a migraine headache, and patients often have completely different migraine triggers. Ultimately, scientists believe that migraines are caused by a combination of hyperactive cranial nerves (which carry a "pain" signal to the brain) and too much inflammation in the brain's protective lining.
Because migraines are so complicated, current pain treatments are often ineffective and can have serious side effects. Cannabinoid administration could provide some patients with effective migraine relief with fewer side effects than current therapies. Cannabinoids bind to two "endocannabinoid receptors" (called CB1 and CB2) expressed in the immune and nervous systems, reducing migraine symptoms in two main ways.
Firstly, cannabinoids reduce migraine symptoms by reducing inflammation. Migraine patients have overactive inflammation in brain's protective linings (collectively called the "meninges"). When the meninges become inflamed and swollen, they activate nerves which transmit a pain signal into the brain. Cannabinoids reduce inflammation specifically by reducing the activity of "mast cells": specialised immune cells that trigger the inflammatory response. By binding to CB1/CB2 receptors expressed in mast cells, cannabinoids stop the release of pro-inflammatory molecules into the meninges, reducing overall swelling and pain.
Secondly, cannabinoids act directly on sensory nerves to reduce the pain signal being transmitted into the brain. Specifically the "trigeminal nerve" is responsible for transmitting pain signals from the scalp, skull, and meninges into the brain. By binding to CB1 receptors located in the trigeminal nerve, cannabinoids reduce the intensity of this pain signal. Cannabinoids also bind to CB1 receptors within the brain itself to further reduce pain.
Cannabinoids reduce both inflammation and pain, making them promising targets for anti-migraine therapies. In fact cannabinoids have anti-nausea and anti-convulsive properties, avoiding some of the nastier side effects of other anti-inflammatory painkillers (like nausea).
Scientists are currently studying the best way to administer cannabinoids to migraine patients. For example, cannabidiol (CBD) is a promising cannabinoid that is legal in many places around the globe, and avoids the psychoactive effects of marijuana. However, more study is needed to determine the best cannabinoid compound and dosage to treat migraine headaches. A detailed review of cannabinoid therapy for migraines can be found here.
Especially in light of increasingly common cannabis legalisation, cannabinoids have a promising future as a treatment for migraine headaches. Cannabinoid therapy can offer life-changing pain relief to migraine patients, greatly enhancing their quality of life.