What Causes Headaches?

Tension and Migraine Headaches: Doctors aren't entirely sure what causes headaches, but they now believe that tension and migraine headaches--even though they lie at opposite ends of the same spectrum--are related to one another. What's more, both headache types are likely inherited: It appears that tension and migraine headache sufferers have a genetically predisposed defect that involves the brain chemical serotonin. This chemical, which seems to be on the tip of every scientist's tongue these days, regulates your mood, how well you sleep, and the narrowing and widening of your blood vessels.

Here's what likely happens when you get a migraine and probably a tension headache, too:

An electrical wave sweeps over the brain.
The electrical activity causes a surge in the serotonin level, which causes blood vessels to constrict.
Serotonin seeps into the surrounding tissues, which lowers the level of serotonin in the brain.
The blood vessels expand and the nerves in the brain become irritated by the lack of serotonin.

What brings on the electrical activity and the rise and fall in serotonin? The answer is triggers.

Common triggers for tension and migraine headaches include:

Stress
Worry
Anxiety
Depression
Anger
Too much or too little sleep
Changes in weather and seasons
Missing a meal
Drinking too much caffeine

Eating certain foods:
Chocolate
Aged cheeses
Citrus fruits
Pickled, fermented, or marinated foods
Cured meats (hot dogs, luncheon meats)
Aspartame (NutraSweet)
Monosodium glutamate (MSG)
Drinking alcohol (especially red wine)
Getting too much sun or overexposure to bright, glaring indoor lights

Female hormones:
Menstruation
Oral contraceptives
Estrogen replacement therapy
Pregnancy
A change in altitude or pressure
Strong odors (perfume, cigarette smoke, paint, etc.)
Motion (in a car or boat)

Cluster Headaches:
Doctors don't believe that cluster headaches, which are potentially the most painful headaches, are inherited. They may, however, be caused by a serotonin imbalance and/or by a defect in the body's biological clock.

Who is affected?

Tension and Migraine Headaches:
At some point in their lives, 90% of people will get a tension headache; migraines affect about 15% of the total population. Both headache types affect women three times as often as men.

Cluster Headaches:
Cluster headaches affect 1% of the population overall, and strike men four times more often than women.