Cluster Headache

The pain comes like a drill. One-sided, behind the eye, so intense that some describe it as the worst pain a human being can experience. It often comes at night — tearing you from sleep as if someone were driving a glowing needle through your eye socket. It lasts thirty minutes, an hour, sometimes three. Then it disappears. And returns the next day. For weeks, sometimes months — in clusters, in series, in waves.

Medically, cluster headache is a neurovascular condition in which blood vessels in the area of the trigeminal nerve dilate and trigger a massive inflammatory response. It affects men significantly more often than women. The attacks often follow a biological clock — always at the same time, like an alarm that delivers pain instead of sound.