In over two dozen studies, disability from the main forms of headache has been quantified (see Table 1). Absenteeism from tension-type headache alone is the equivalent of 0.4 to 1.2 days per year for every person in the workforce (Pryse-Phillips, Findlay, Tugwell, Edmeads, Murray, & Nelson, 1992; Schwartz, Stewart, Simon, & Lipton, 1998). Migraines cause the average sufferer to lose approximately 4.6 workdays annually (e.g., Steiner, Scher, Stewart, Kolodner, Liberman, & Lipton, 2003; Von Korff, Stewart, Simon, & Lipton, 1998). With a 1-year migraine prevalence of about 10% in the United States and Europe (Rasmussen, 2001), this translates to 0.5 days per year of migraine-related absenteeism in the general population.