Migraine is a neurological syndrome characterized by altered bodily experiences, painful headaches, and nausea. It is a common condition which affects women more frequently than men.
The typical migraine headache is one-sided and pulsating, lasting 4 to 72 hours. Accompanying complaints are nausea and vomiting, and a heightened sensitivity to bright lights (photophobia) and noise (hyperacusis).  Approximately one third of people who experience migraines get a preceding aura, in which a patient may sense a strange light or unpleasant smell. 
Although the exact cause of migraine remains unknown, the most widespread theory is that it is a disorder of the serotonergic control system. Recently, PET scans have demonstrated the aura to coincide with spreading cortical depression after an episode of greatly increased blood flow (up to 300% higher than baseline). There also appear to be migraine variants that originate in the brainstem and involve dysfunction in calcium and potassium ion transport between cell membranes. Genetic factors may also contribute. Studies on twins show that genes have a 60 to 65% influence on the development of migraine. Fluctuating hormone levels show a relation to migraine in several ways: three quarters of adult migraine patients are female while migraine affects approximately equal numbers of boys and girls before puberty, and migraine is known to disappear during pregnancy in a substantial number of sufferers.
Migraine is three times more common in women than in men. Some people can tell when they are about to have a migraine because they see flashing lights or zigzag lines or they temporarily lose their vision.
Many things can trigger a migraine. These include:
- Lack of food or sleep
- Exposure to light
- Hormonal changes (in women)