Chronic Migraine vs. Episodic: What You Need to Know

Migraine is not just a really, really bad headache. It is an illness with a constellation of neurological symptoms, including really, really bad headaches, usually on only one side of the head. The symptoms vary from person to person but can include nausea, vomiting, dizziness, and sensitivity to touch, smells, and light, and in a few people, numbness and difficulties with speech.

More than 37 million Americans, including children, suffer from migraine, according to the National Headache Foundation (NHF). The condition often starts in childhood; in fact, half of all people with migraine experienced their first attack before age 12, and children as young as 18 months have been known to have migraine.

Episodic vs. chronic

Most migraine sufferers get a headache every few months or less often; this is called episodic migraine. But some people have attacks much more frequently. When migraines occur 15 or more days per month over a period of three months or more, the condition is called chronic migraine.

Episodic and chronic migraine are not two separate illnesses, explains Robert Pearlman, M.D., associate professor of neurology at the University of Alabama at Birmingham Hospital. “Migraine is there all the time,” he says, “but people with chronic migraine have more attacks.”

According to Juliette Preston, M.D., director of the headache clinic at Oregon Health & Science University in Portland, over time people with episodic migraine may develop more and more headaches for various reasons, including changes in hormones, increased stress, illness, or simply an increase in the use of pain medications. Having more headaches decreases the threshold for new headaches, and the condition can become chronic and less responsive to medications.

Why me?

Both genetics and environment play a role in who gets migraine. Four out of five people who suffer from migraine have a family history of the illness. According to the NHF, if one of your parents has migraine, you have a 50 percent risk of having it as well. If both parents do, that risk is 75 percent.

Caffeine, some foods, certain medications, stress, and changes in weather or routines can trigger attacks. It is important to understand that a trigger isn’t the same thing as a cause; a trigger is just something that is likely to set off a migraine attack at any given time. Triggers vary greatly from person to person, and can even vary for the same person—something that triggers an attack one day might not have that effect on another.

The cause of migraine is something else entirely, and in some ways, more mysterious. “No one knows for sure exactly what causes migraine,” explains Pearlman, “but changes in the levels of serotonin and other neurochemicals are definitely involved. This affects the trigeminal nerve system, a constellation of nerves in the face and head. The thinking now is that patients with migraine have some basic neurological problem that manifests as migraine headaches.”

Both men and women get migraine. Prior to puberty, boys are more likely to experience attacks than girls, but women are three times more likely to suffer from migraine than men. It is not entirely clear why.

Many women find that they are more likely to have headaches just before or during their periods, and often women find that their migraines lessen after menopause. This suggests that hormones (probably estrogen) are involved. However, the situation is likely more complex than that, says Dr. Preston. “Estrogen is a trigger for some women, but not all,” she says. “Some women find that their headaches lessen after menopause, but others, unfortunately, do not.”

The burden of migraine

It is hard to overestimate the costs, both personal and economic, of suffering from migraine.

When you have a migraine, it is difficult, if not impossible, to work, study, or conduct any of the routine activities of daily life. Add to that the fact that attacks typically last between four and 72 hours (and in some cases as long as a week), and it’s not surprising that, according to the Migraine Research Foundation, migraine in general is one of the top 20 most disabling illnesses, and chronic migraine much more so.

“If you have chronic migraine, it can be very difficult to maintain employment or keep up in school. It really changes daily life,” says Pearlman. “When you’re experiencing an attack, you’re just miserable; you’re unable to do much of anything.”

The good news is that complications from migraine are rare. “Generally, there is no long-term issue,” says Pearlman, “though there may be a slight increase in the risk of stroke for some people with migraine with aura.”