A hypnic headache is a rare headache form that occurs in people between the ages of 40 and 80. It is unique in that it is a headache that occurs exclusively at night, typically lasting between 15 and 60 minutes. The headaches tend to occur at the same time each night tend to be global (not just on one side) and are not associated with runny nose, tearing or other "cluster" features. There are specific treatments for this kind of headache which does not typically respond to the usual headache medications.