We’ve been trying to cure migraines – without much success, until relatively recently – for as long as we’ve been able to identify them as a distinct ailment. The Ebers Papyrus, a scroll dating back to 1550BC that mentions a “disease of one half of the head”, suggests anointing the scalp with fried catfish; Galen, the second-century Roman physician whose term “hemicrania” evolved into the modern word, recommended blood-letting (this, to be fair, was his answer to a lot of things). By the 20th century, doctors were suggesting repressed emotions might be at fault, leading to suggestions that women – who suffer from migraines far more than men – were simply too fragile and neurotic. As recently as a couple of decades ago, “vascular theory” – the idea that blood vessels in the brain expanding and contracting were to blame – was still the standard explanation in many medical schools.
Over the last decade, though, our understanding of what causes these neurological disorders, which are technically a sub-category of headache, has progressed enormously, alongside the options for treating them. One of the biggest problems, as in centuries past, is a lack of sympathy for sufferers. The biggest difference, these days, is that we actually understand what is happening, and why.
Before we get into the brain science, it’s helpful to understand that headaches, more generally, fit into two broad categories: primary headaches, which don’t come from any underlying structural cause, and secondary headaches, which could be caused by anything from stroke, meningitis or a tumour, to bleeding on the brain. A hangover, which is caused by a number of factors (some of them related to dehydration), is secondary – but a cluster headache, a very unpleasant neurological condition that can be triggered by alcohol in a matter of minutes, is primary. Migraines are primary, but are frequently mistaken for secondary: one of the many reasons that sufferers have often been poorly served.
“As doctors, we’re taught to ask the right questions to determine which type of headache it is,” says Alexandra Sinclair, a professor of neurology at the University of Birmingham and chair of the British Association for the Study of Headache. “We use the International Headache Society classification, which you can see online – but actually, for the individual patient, many headaches feel quite similar, so the precise classification can be difficult to understand. Generally, though, a headache that is moderate to severe, where a patient wants to lie down, keep away from light, and noise, keep still, may feel nauseated, and feels pounding pain, often on one side – that’s most often going to be migraine.”
Migraines, we now understand, come from the activation of the trigeminovascular system – a network of nerves and blood vessels that detects pain in the brain. The core of this system is the largest and most complex sensory nerve in your head: the trigeminal nerve, which deals with sensory information (including touch, pain, temperature) and motor control (chewing). When something goes wrong, the nerve fibres in this system pump out a chemical called CGRP (calcitonin gene-related peptide), which activates the brain’s pain network and causes headaches that range from moderate to crippling.
Something else that’s now better understood is that migraines typically occur over four phases, including a warning period that might include excess yawning, urination or fatigue. A common occurrence at this stage is odd food cravings – which can lead to an element of victim-blaming. “Historically, there used to be a sense of ‘Well, you may have caused your headache by eating a piece of cheese or chocolate,’” says Prof Sinclair. “But actually, the research has completely turned that upside down. Functional brain imaging shows activation of the brain areas that might make you crave food in the 24 hours or so before the actual pain. Hence, you didn’t cause the migraine – the migraine caused the craving.”
After this period – technically called the “prodrome” – about 30% of sufferers experience what is known as the “aura”, which can include visual disturbances, numbness in the face or arms or legs, or speech difficulties. Then there’s the migraine itself, which typically lasts anywhere from four to 72 hours. Then finally the “postdrome”, where you may feel washed out or exhausted for up to two days. It’s typically only after that, after several days of disruption to your body’s typical way of functioning, that things go back to normal.
Like other systems in the body, this network of sensations probably evolved for good reasons. “There are schools of thought that would say that when you get meningitis or when you have a head injury or something going on in your brain like a tumor, you may be primed to get more headaches, which actually may be good – because it alerts you that something’s happened within your brain,” says Prof Sinclair. “There are also schools of thought that say that back in our caveman days, if you were primed to have migraines, you’d be quite vigilant, to noise, light, or movement – you probably wouldn’t be sleeping deeply – and so those genes might have stayed with us by giving humans a survival advantage.”
This, in a nutshell, is the issue for severe migraine sufferers. Hormonal, lifestyle and even environmental changes can change your susceptibility to what is technically a neurological disease, but you can also have a brain that’s genetically primed to be more headache-prone. These days, of course, more of us are working in fluorescent-lit offices than keeping watch around a campfire – and if a migraine hobbles our ability to get any work done for most of the week, then it’s no longer a survival advantage (the World Health Organization, for instance, lists migraine in the top 10 “most disabling” diseases globally).
“It affects a huge number of people for what should be the most productive years of their lives, frequently between puberty and menopause,” says Prof Sinclair. “For some people, their ability to function properly is impaired for much of the month – and then there’s the stigma around it not being a ‘real’ issue, and being sort of pushed to the back of the queue for medical treatment.” About twice as many women seem to suffer from migraine as men, for reasons that run from hormonal differences to differences in brain susceptibility to pain chemicals. That might be another reason it traditionally hasn’t been treated seriously enough.
There are things sufferers can do to mitigate the likelihood of migraine: lack of sleep, too much sleep, caffeine withdrawal, dehydration and significant stress all play a part. Screen time, according to the available evidence, presents a murkier picture: migraine sufferers are typically sensitive to light, but it’s not totally established that there’s a correlation between phone or monitor use and the onset of attacks.
The good news? The identification of CGRP means that migraine treatments are now improving rapidly, consisting of inhibitors built specifically to block the pain chemical. “We have a class of drugs usually taken as a tablet called Gepants that work by blocking the CGRP receptor,” says Prof Sinclair. “We also have CGRP monoclonal antibodies, often referred to as Mabs, which are typically administered via monthly injection. Together, they have truly revolutionised headache care over the last four or five years.” The problem is, these treatments are expensive, and can be difficult to access. “We need more healthcare professionals able to provide headache management, alongside a simpler prescribing process, so patients can access treatment when they need it and recover faster,” says Prof Sinclair. “But we also need to educate patients to seek help. Effective management is essential and can sometimes be the difference between losing your job or keeping it. So I think it’s really about understanding that, if you’re a migraine sufferer, things really have changed.”
Headaches might not have altered in 2,000 years, but thankfully we’ve moved past seeing them as a badge of character.
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