The voluminous scientific literature on the subject of migraine is typical of a disorder of unknown cause. Consequently, it has become difficult to ascertain whether the complexities of the syndrome reflect the nature of the disorder or the multiplicity of causal theories. Surprisingly, there has been little attempt to formulate a unifying hypothesis that would take into account all previous major etiologic concepts. In early years, migraine was attributed to psychologic disturbances. The work by Olesen et al1,2is one of the latest milestones in clearly establishing the organic nature of migraine. The following discussion perhaps represents the marriage of these two schools of thought by adopting the view that migraine is a biobehavioral disorder. The various organic theories for the cause of migraine fall into three broad categories of origin: systemic, neurovascular, or central nervous system (CNS). Unfortunately, during the the-orizing process, cause has become confused with