Women's Brains More Likely to Trigger Migraines

The mechanism of the female brain may be more likely to cause migraine headaches than a man's brain, according to a new animal study from the University of California - Los Angeles.

The study, published in the current issue of Annals of Neurology, found that women are more likely to experience a certain type of brain activity called cortical spreading depression, which is thought to be one of the causes of a migraine headache. During an episode of CSD, the brain undergoes waves of excitability, causing pain as well as nausea and dizziness - three of the classic symptoms of migraine.

During the course of the study, researchers observed brain activity in both male and female mice, and found that female mice were much more susceptible to the CSD trigger than their male counterparts.

"The results were very clear," said researcher Dr. Andrew Charles, who is also the director of the Headache Research and Treatment Program in UCLA's Department of Neurology, in a press release. "The strength of the stimulus required to trigger CSD in males was up to two or three times higher than that required to trigger the response in females."

Women experience migraines about three times as often as men. Hormonal changes during women's menstrual cycles have long been thought to be at least part of the cause, but the results of this study did not appear to be affected by that factor.

"We didn't monitor the estrous cycle in the female mice, so it's likely we sampled from different estrous phases in different animals," Charles said in the release. "Yet we still found a consistent difference in the CSD threshold between males and females."

The study results are promising for the development of new migraine medications. In another study, the same researchers have discovered that an Alzheimer's Disease medication, memantine (brand name: Namenda), appears to inhibit episodes of CSD and has been effective for some patients who get migraines frequently. Of the 54 people studied, 38 reported a significant reduction in the frequency of their headaches after being on the drug for at least two months. This study will be published in the September issue of the Journal of Headache and Pain.

A migraine headache, characterized by intense pain, sensitivity to light, and nausea, is a common phenomenon. According to the American Headache Society, the number of migraine sufferers ("migraineurs") increased from 23.6 million in 1989 to 27.9 million in 1999.

The entire mouse study can be read online at http://www3.interscience.wiley.com/cgi-bin/fulltext/114230925/HTMLSTART (fees apply).

Newswise press release. "Why Women Get More Migraines Than Men." http://www.newswise.com/articles/view/532199/?sc=mwhn

American Headache Society. "Migraine in Women." http://www.achenet.org/education/patients/MigraineinWomen.asp