The Facts

In North America, more than 1 in 10 people have migraine headaches. Most migraine sufferers are women. Migraines usually appear between the ages of 10 and 40. After the age of 50, they tend to disappear, especially among women after menopause.


Migraine is a complex disorder involving the brain and the blood vessels around the brain and head. The brain may become hyperactive in response to certain environmental triggers, such as light or smells, for reasons that are not known. This starts a series of chemical changes that irritate the pain sensing nerves around the head and cause blood vessels to expand and leak chemicals which further irritate the nerves.

While migraine does seem to run in families, a clear genetic cause has only been nailed down for one rare type of the disease called familial hemiplegic migraine.

Although we don't know the precise causes of migraine, we are aware of potential triggers – habits and circumstances that are associated with the onset of a migraine headache.

The number one trigger is hormonal changes. Two-thirds of women sufferers only get their headaches around the time of their period. Migraines in women are usually worse around puberty and they tend to disappear around menopause.

Another common migraine trigger involves food. The most common culprits are:

  • alcohol, especially red wine and beer
  • tobacco
  • aged cheeses
  • chocolate
  • fermented, pickled, or marinated foods
  • monosodium glutamate (MSG)
  • aspartame
  • caffeine

Other triggers include:

  • stress
  • hunger
  • changes in sleeping patterns
  • changes in barometric pressure

Symptoms and Complications

Migraine headaches are more severe and last longer than regular "tension" headaches. The pain is more localized, often concentrated over one eye. Severe headaches that affect only one side of the head are generally due to migraines. Migraine headaches are often associated with nausea and vomiting as well as hypersensitivity to light and noise. The headaches are often made worse by movement or bending over. As a result, migraine sufferers tend to lie still in a dark, quiet room and avoid any type of stimulation.

About 1 in 5 migraine sufferer experiences an "aura" just before the headache comes on. Auras are visual effects that can include flashes of light, lines with vivid colours, or double vision. Occasionally patients may feel weak or slur their words. These symptoms usually disappear after 15 to 30 minutes, only to be replaced by crushing pain and, in some cases, severe nausea.

Migraine headaches should not be confused with rebound headaches (also called medication overuse headaches). Rebound headaches can strike anyone who uses ASA* (acetylsalicylic acid) or other simple pain medications (such as acetaminophen or ibuprofen) for headache pain on more than 15 days a month. They can also occur for people who use narcotic pain relievers (e.g., codeine), medications containing more than one pain reliever, or "triptan" medications (e.g., almotriptan, rizatripan, sumatriptan) on more than 10 days a month. Sometimes these rebound headaches are called medication-induced headaches. The medicine works for a little while, but as it wears off, the pain comes back with a vengeance. If you turn to pain medications for relief, the vicious cycle often continues. The end result is a constant dull headache, affecting both sides of the head. It tends to worsen each time the pain medication wears off. If you think you might have rebound headaches, talk to your doctor about the best way to manage them.

A long-term study suggested that women with migraine have a higher risk of stroke. Migraine generally affects young people, and stroke is rare in this population. The relationship between migraine and stroke is still unclear and further studies are needed.

Making the Diagnosis

None of the common diagnostic tests for the brain (e.g., CAT scan) are successful at detecting migraine, although they may be used to rule out other causes of headache. Doctors rely on a person's symptoms to diagnose the disorder. Your doctor may ask you to keep a headache diary to help diagnose migraine.

Treatment and Prevention

Sometimes you can cut down the number of migraine headaches you have by avoiding potential triggers. Identifying migraine triggers isn't easy. Many doctors recommend keeping a headache diary. By recording the circumstances (e.g., emotions, foods eaten) surrounding your migraines, you may eventually figure out what situations to stay clear of to reduce your risk of migraines.

There are some measures you can take to help reduce the number of migraine headaches: avoid sleep deprivation and undue stress and maintain a regular exercise program and good nutrition. Other techniques such as yoga, meditation, and biofeedback techniques may also be helpful. When these measures do not solve the problem, medication may be required. Document the techniques you've tried and how well they worked in your headache diary, too.

There are two basic types of migraine medication: abortive medications are used to control the symptoms of an existing migraine headache, and prophylactic medications are taken to prevent migraine headaches. The choice of treatment depends on the severity of migraine, other medical problems, and on how often migraines occur.

Abortive medications include:

  • pain medications that contain ASA, acetaminophen, non-steroidal anti-inflammatory agents such as ibuprofen, or naproxen for mild to moderate migraine headaches
  • ergot preparations such as ergotamine or dihydroergotamine (DHE) that constrict dilated blood vessels
  • triptans (e.g., sumatriptan, naratriptan, zolmitriptan, rizatriptan, almotriptan, frovatriptan, eletriptan) that mimic the chemical messenger serotonin, constricting blood vessels to relieve pain
  • metoclopromide, chlorpromazine, prochlorperazine, and dimenhydrinate may also be used

Prophylactic medications include:

  • antiseizure medications such as valproic acid, divalproex sodium, gabapentin, and topiramate – these may stabilize nerve cells and prevent the brain hypersensitivity that triggers the migraine
  • blood pressure medications such as beta-blockers (e.g., propranolol or metoprolol), candesartan, lisinopril, and calcium channel blockers (e.g., flunarizine and verapamil) – these can prevent headaches by stabilizing blood vessels
  • riboflavin (vitamin B2), coenzyme Q10, or magnesium supplements – these may be used for people who are concerned about medication side effects
  • serotonin blockers such as pizotifen may also be effective
  • tricyclic antidepressants such as amitriptyline and nortriptyline – these work like pain medications at lower doses and increase the levels of certain brain chemicals

A headache specialist might recommend other therapies:

  • There are herbal products like butterbur that might help prevent migraines.
  • Relaxation therapy and biofeedback aim to teach people to control body functions such as temperature and pulse.
  • Behavioural therapy involves learning how to avoid headache triggers by changing behaviour.

There is some evidence that suggests chiropractic care, such as spinal manipulation, can help alleviate pain associated with migraine that originates from the neck.

*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.