Introduction to the Special Series on the Chronification of Headache: Mechanisms, Risk Factors, and Behavioral Strategies Aimed at Primary and Secondary Prevention of Chronic Headache

Abstract

The transformation or clinical progression of headache from episodic to “chronic daily headache” is a well-evidenced and long-recognized phenomenon. Citing several demonstrations of brain abnormalities in migraineurs (eg, brain infarction and white matter lesions, iron deposits in periaqueductal gray correlating with headache duration, central sensitization), Lipton and Pan suggested that clinical progression may be accompanied by progressive changes in the brain and that in some cases it could be conceptualized as a chronic progressive disorder. While migraine progresses in some patients, it does not progress in all or even most patients, leading Bigal and Lipton to conclude that migraine is best understood as a chronic disorder with episodic attacks and that it is progressive in some patients. The conceptualization of migraine, chronic daily headache, and perhaps eventually other forms of chronic headache, as sometimes progressive disorders highlights the importance of identifying potentially modifiable risk factors associated with onset and progression, screening and risk factor modification (primary prevention), and early intervention to limit progression (secondary prevention). Clear identification of such risk factors could provide a foundation for the development of preventive interventions. Some of the risk factors for headache chronification identified to date are nonmodifiable (eg, age, low socioeconomic status, head injury), other risk factors have a key behavioral component that can be recognized and modified. Thus, screening and behavioral risk-reduction (ie, behavioral self-management) strategies may serve to prevent chronification. Analgesic overuse is probably the most widely recognized and best empirically established risk factor associated Address all correspondence to Donald B. Penzien, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.