NEW YORK (NYTIMES) - If you do not suffer from migraine headaches, you probably know at least one person who does.

Nearly 40 million Americans get them - 28 million of them women and girls - making migraine the second most disabling condition in the world after low back pain. Several studies have found that migraine became more frequent during the pandemic too.

Despite its ubiquity, research on migraine has long been underfunded.

The National Institutes of Health spent only US$40 million (S$55.2 million) on migraine research in 2021. By comparison, it spent US$218 million researching epilepsy, which afflicts one-twelfth as many Americans.

Why is this devastating condition so woefully understudied?

"It's a woman's disease," said Dr Robert Cowan, a neurologist and a former director of the Stanford Headache Program. In other words, he said, sexism almost certainly plays a role in medicine's apathy towards the condition.

The good news is that over the past several years, the medical establishment has become more interested in the issue, and a handful of new treatments for migraine have been approved by the Food and Drug Administration (FDA).

Here is what migraine sufferers should know.

Recognise the symptoms of migraine and get a diagnosis

Far too many people with migraine suffer in silence.

"Fewer than 30 per cent of people suffering with migraine seek medical advice, and only some of those patients will receive an appropriate migraine treatment," said Dr Santiago Mazuera, a neurologist at the Sandra and Malcolm Berman Brain & Spine Institute in Baltimore.

Migraine is a neurological disorder and it differs from garden-variety headaches.

People are likely to suffer from migraine if they have had at least five headache attacks in their lives, each lasting between four and 72 hours, and if the pain fulfils two out of these four criteria: It throbs or pulsates; it is on one side of the head; it is moderate to severe; and it worsens with activity. Also, these attacks must cause either nausea or sensitivity to light and sound.

If you think you might have migraine, see your primary-care practitioner, Dr Mazuera suggested. "There is better understanding of migraine within the primary-care community in recent years and more knowledge about the newer treatments," he said.

But if you are not getting the help you need, you might want to see a headache specialist or neurologist, said Dr Seniha Ozudogru, a neurologist at Penn Medicine. People with migraine are also at increased risk for other disorders, including heart disease, stroke, epilepsy, anxiety and depression.

Try lifestyle changes and first-line treatments for a start

If you have migraine, consider keeping a headache diary, or downloading a migraine app, to identify possible triggers.

Women, for instance, often have migraine pain right before their period. It can be treated in a variety of ways, including with an oestrogen patch, Dr Cowan said.

Other common migraine triggers include stress, too much or too little sleep, caffeine, alcohol, weather changes, certain foods, dehydration, light and particular smells, according to the American Migraine Foundation.

Often, triggers are partial and additive. You might not get a migraine attack after drinking one glass of red wine, but a glass of red wine and a bad night's sleep might do it, Dr Cowan said.

A headache diary can also help you identify your triggers and figure out if you have chronic migraine, which is defined as having headaches on 15 or more days a month for more than three months, and when at least eight of those headaches have migraine-like features.

Based on the symptoms and their frequency, your doctor may recommend a preventive migraine treatment to stop the headaches from starting. These types of medicines include antidepressants such as amitriptyline, blood pressure medications such as propranolol and epilepsy drugs including valproate, Dr Cowan said.

The problem with these drugs is that often "they have nasty side effects", he said, so they are not always recommended or tolerated.

If you cannot get relief, discuss new treatments with your doctor

Over the past five years, a handful of new drugs and devices have been approved for prevention and acute treatment of migraine.

Many of these drugs block the activity of a pain-related protein called CGRP, said Dr Ozudogru.

These include, for migraine prevention, monoclonal antibodies that are periodically injected or administered intravenously. There are also pills, called gepants and ditans (with brand names like Nurtec ODT, Ubrelvy and Reyvow) that can be taken at the onset of migraine to block the activity of CGRP.

Rimegepant (Nurtec ODT) has been approved by the FDA to both prevent and treat migraine, Dr Ozudogru said, which is notable because most drugs do only one or the other.

These drugs do not seem to have significant side effects, Dr Cowan said - though they can cause mild nausea - yet they are not usually prescribed until after a person has tried several first-line treatments. That is in large part because the new drugs are expensive, he said.

Dr Ozudogru said some doctors are also cautious about trying the latest treatments because they are so new, and nobody can say how safe they are over the long term.

Among other things, CGRP helps the body heal from strokes, so drugs that inhibit CGRP activity might hinder recovery in someone who has a stroke, she said.

Another medication that has been approved to treat chronic migraine in particular is the cosmetic drug Botox. It is injected into areas around the head and neck, and is thought to work by blocking chemicals that carry pain signals to the brain.

"I like Botox a lot," Dr Cowan said. But, he added, "not everybody can tolerate being stabbed in the head 31 times, even with a tiny needle". Usually, too, Botox treatment is repeated every 12 weeks.

Several medical devices have also been approved in recent years to manage migraine. "These have good data," Dr Cowan said, and they are ideal for people who cannot tolerate medicines or are pregnant.

GammaCore, a hand-held device, targets the vagus nerve in the neck. Nerivio, a smartphone-controlled device worn on the arm, uses electrical signals to disrupt pain pathways. Cefaly stimulates the trigeminal nerve on the forehead, and Relivion stimulates the trigeminal and occipital nerves.