Headache attributed to psychiatric disorders.

The association between psychiatric illness and headache is widely recognized. "Headache attributed to psychiatric disorder" is a new category of secondary headache introduced in the 2004 revision of the International Classification of Headache Disorders (ICHD-II) (Headache Classification Subcommittee of the International Headache Society, 2004). It represents a new, but not conclusive, step toward a better systematization of the topic "headache and psychological factors." From the early 1990s the involvement of psychological factors in headache disorders has been clearly identified as "psychiatric comorbidity." The current conceptualization of the term implies an association, more than casual, but likely not causal, between an index disease or disorder and one or more coexisting physical or psychological pathologies. Additionally, clarifying the direction, meaning, and weight of comorbidities has pathophysiological, nosological, course, and treatment implications. However, the study of comorbidity may present a series of difficulties related to the current understanding of the etiology and pathophysiology of diseases at the center of our attention. Sometimes, as happens in the subject of headache, we proceed against a background where many issues need to be clarified. In this chapter, we analyze the past and current literature, tracing the line from "migraine personality" to "psychiatric comorbidity" to "headache attributed to psychiatric disorders." Questions related to etiology, pathophysiology, and treatment options are discussed for different headache subtypes.