Migraines affect at least 2.7 million Canadians a year, but for all their familiarity, they are still painfully disruptive.
Migraines are also mysterious. Over the centuries, migraines have been assigned a range of causes, including: possessing a volatile spirit or an overly warm constitution, suffering from excessive vapours of the stomach, being poor and a mother, being a woman and unmarried, and being a woman who feels feelings. Currently, doctors define migraines as a neurological condition, although the origin story for these super-villains is still hazy.
Some people are genetically predisposed to migraines – that’s one thing we know for sure. We also know they can be triggered by bright lights, strong smells, certain foods, and hormonal fluctuations.
But a trigger is not a cause, and researchers are still theorizing on why they happen in the first place. Some say migraines are the result of a hyperactive brain stem, others think they can occur when a body doesn’t supply enough of its own cannabinoids. (And yes, if you think that theory is suggesting that people get migraines when they don’t get enough cannabis, it kind of is. More on that one below.)
Migraines: they’re not just headaches
Migraine pain is typically experienced in the head, but a migraine is more than a headache. Along with throbbing in the head, symptoms can also include nausea, vomiting and blurred vision, as well as sensitivity to light, sound, smell and touch.
A typical migraine takes four to 72 hours to run its course, but its consequences last longer. A 2014 Statistics Canada report found that people diagnosed with migraines report a variety of adverse social, physical and psychological outcomes.
“I think the key finding that was quite interesting was the impact of migraine,” said the report’s author, Pamela Ramage-Morin, in an interview with CBC. “For three-quarters to say that it had an impact on their getting a good night sleep, over half said it prevented them from driving on some occasions, even people feeling left out of things because of their condition. There’s some social isolation that could be occurring. It may be limiting on people’s education and employment opportunities. That can have a long-term effect.”
How cannabis helps
Cannabis is one of migraine’s most enduring treatments, and has been in continuous use as a headache therapy for more than four thousand years. Cannabis fell out of favour with Western doctors in the mid-20th to early 21st century, when it was illegal, but even skeptics are likely to agree that it’s a more appealing treatment than other historical migraine remedies. (Depending on the century, migraineurs could expect to have any of the following applied to their heads: earthworm poultices, hot irons, heated glass tubes, leeches, magnets, electricity and dead moles.)
Cannabis likely helps migraines on several fronts: it’s a well-established anti-inflammatory agent, with pain and nausea-relieving qualities. It’s also promising as a treatment for neuropathic pain, which is notable because some researchers believe migraines may actually be a neuropathic syndrome, caused by inflammation arising in the nervous system. Additionally, cannabis can provide powerful distraction from pain, allowing migraineurs to disassociate from the unpleasantness of an attack.
A 2017 pilot study found that cannabis was “just as suitable as a prophylaxis for migraine attacks as other pharmaceutical treatments,” producing a little more than a 40 per cent reduction in attacks after three months’ treatment.
Could endocannabinoid deficiency cause migraines?
Clinical endocannabinoid deficiency (CED) is not a diagnosis, but a theory that proposes that migraines – as well as fibromyalgia and irritable bowel syndrome (IBS)– are caused by insufficient endocannabinoid levels. Humans naturally produce endocannabinoids, which derive their name from the fact that they are naturally present, or endogenous, and because they behave like cannabinoids, the active ingredients in cannabis.
Every human has an endocannabinoid system (ECS), which regulates a range of processes, including pain, appetite, digestion, memory, fertility, inflammation, immune response, and more. Naturopathic doctor Jacqueline Jacques calls it “the most important system you’ve never heard of.”
The first cannabinoid receptor was discovered by molecular biologist Lisa Matsuda in 1990. Nearly a decade later, neurologist and psychopharmacology researcher Ethan Russo suggested CED as a possible explanation for fibromyalgia, IBS and migraines. In 2016 he revisited his theory with a comprehensive review of new studies that support it.
We have plenty of clues, but it will be some time before we have a precise understanding of why cannabis works on migraines – and why migraines happen in the first place. In the meantime, there’s a mounting body of studies that show chronic pain patients who use medical cannabis report substituting it for pharmaceutical pain medications, with fewer side effects and better pain management.