Chronic Migraine

What is Chronic Migraine?

What is chronic migraine? The International Headache Society's International Classification of Headache Disorders, 2nd edition, has defined chronic migraine as 15 or more migraine days a month in someone with no medication overuse that has lasted for three months or more. A revised version of this diagnostic criteria has been proposed for inclusion in the next edition. These are 15 or more headache days a month, at least 8 of which are migraines, and present for three months or longer. (And without evidence of medication overuse.)

What Causes Chronic Migraine?

Why some people get chronic migraine and some people don't is not always entirely clear. There is some evidence that chronic migraine may be on a spectrum of headache frequency between episodic migraine (less than 15 days a month) and transformed migraine, which is migraine occurring very frequently, similar to chronic daily headache, but with clear migraine features to the headaches. Research into why headaches become chronic has shown the following risk factors for headache chronicization. This research did not focus on chronic migraine specifically, but looked at chronic daily headache.

Risk factors for chronic migrane are:

  • History of head or neck trauma
  • Female
  • Habitual snoring
  • Sleep apnea and other sleep disorders
  • Obesity
  • High caffeine intake
  • Smoking
  • Coexisting pain disorders
  • Overuse of pain medications
  • Major life changes (moving, getting married, etc.) were associated with the onset of chronic headache

What Can You Do About Chronic Migraine?

If you have any of the risk factors above, work with your doctor to minimize the ones you can control. However, not everyone with chronic migraine will necessarily have something on this list.

It's best to be certain that you are not overusing abortive migraine medication, and that you are on an effective prevention regimen.


1. Bigal ME, Rapoport AM, Sheftell FD, Tepper SJ, Lipton RB. Chronic migraine is an earlier stage of transformed migraine in adults. Neurology. 2005;65(10):1556-1561. Available at: [Accessed July 17, 2010].
2. Olesen J, Bousser M, Diener H, et al. New Appendix Criteria Open for a Broader Concept of Chronic Migraine. Cephalalgia. 2006:742 -746. Available at: [Accessed July 17, 2010].
3. Bigal M, Sheftell F, Rapoport A, Lipton R, Tepper S. Chronic Daily Headache in A Tertiary Care Population: Correlation Between the International Headache Society Diagnostic Criteria and Proposed Revisions of Criteria for Chronic Daily Headache. Cephalalgia. 2002:432 -438. Available at: [Accessed July 17, 2010].
4. Scher AI, Stewart WF, Lipton RB. Caffeine as a risk factor for chronic daily headache: A population-based study. Neurology. 2004;63(11):2022-2027. Available at: [Accessed July 17, 2010].
5. Scher A, Lipton R, Stewart W. Habitual snoring as a risk factor for chronic daily headache. Neurology. 2003;60(8):1366-1368. Available at: [Accessed July 17, 2010].
6. Katsarava Z, Schneeweiss S, Kurth T, et al. Incidence and predictors for chronicity of headache in patients with episodic migraine. Neurology. 2004;62(5):788-790. Available at: [Accessed July 17, 2010].
by Christina Peterson, M.D.
updated July 17, 2010