The underlying causes of migraines are unknown; however, they are thought to be caused by both environmental and genetic factors. They run in families in about two-thirds of reported cases.
There are four stages of a migraine headache, although all people do not experience all of the stages. These stages include the Prodrome, Aura, Headache, and the Postdrome.
The first phase is the Prodrome, occurring in about 60% of those with migraines. The Prodrome has an onset anywhere from two hours to one or two days before you experience a migraine, when you may begin to notice some subtle changes. These changes can include depression, constipation, food cravings, hyperactivity, irritability, stiffness in your neck, and sometimes uncontrollable yawning. Other changes may occur. Every person is unique.