Chronic migraine and chronic tension-type headache: are they the same or different?

The question in the title of this article arises from ambiguities in the diagnostic criteria for chronic migraine (CM) included in the 2004 International Classification of Headache Disorders, 2nd Edition (ICHD-II), and in the 2006 revision. More broadly speaking, it also arises from the fact that to date the general subject of chronic daily headaches (CDH) has not been approached in a correct and appropriate way. For all its limitations, ICHD-II has unquestionable merits and remains a fundamental tool. However, it is a tool that gets a snapshot picture of headache; so, it is not applicable to a dynamic form that evolves from and is transformed by a chain of events. If these events are ignored, there will be no accurate interpretation of the final clinical picture. Today, we still do not have any classification of headache syndromes to complement ICHD-II. Currently, then, the only way to approach the CDH issue is to put patients at the center and to focus on their life histories. If we reason strictly in terms of diagnostic classification criteria, which for this headache subtype are artificial and ambiguous, we may have trouble finding an answer to the title question. However, if we reason in broader clinical terms, putting at the center of our reasoning not only headache features, but patients with all their histories, the answer can only be that CM and chronic tension-type headache are two different clinical entities.