About 1 out of 8 Americans has migraines. They usually begin during the teenage years. After puberty, migraines are more likely to affect girls and women.
Experts still aren't sure what causes these headaches. But they seem to involve a wave of unusual activity in brain nerve cells, along with changes in blood flow in the brain.
Though migraines can trigger severe pain in the head, they aren't simply headaches. They often also cause other uncomfortable symptoms, such as: