A community-based sample of 122 adolescents aged 12-14 years with chronic daily headache (CDH) was established in 2000 at University centers in Taiwan by a survey of 7,900 students in 5 selected public middle schools. CDH was defined as >15 headache days/month, average >4 hours/day for >3 months. At short-term 1 and 2-year follow-up, CDH persisted in 40% subjects in 2001 (average monthly headache frequency of 11.0+/-9.7 days), and in 25% subjects in 2002 (7.7+/-6.5 days). At long-term 8-year follow-up, the headache profile for the past year was determined by the Migraine Disability Assessment (MIDAS) questionnaire. Outcome measures were headache frequency, MIDAS score, and presence of CDH in 2008. When re-interviewed by physicians via telephone, of a total of 103 subjects who completed the study, 26 were male and 77 were female, mean age 21.6+/-0.9 years. Moderate or severe headache disability (MIDAS >11) persisted in 28 (27.2%) subjects. Of 12 (12%) who met CDH criteria in 2008, 10 (83%) had chronic migraine, the most common subtype; 2 (2%) overused medication. Migraine diagnosed at baseline predicted poorer outcome after 8 years follow-up. CDH onset <13 years of age, duration >2 years, and medication overuse were predictive of either higher headache frequencies or CDH in 2008. 
COMMENT. Chronic daily headache in adolescents resolves in 75% subjects at 2-year follow-up, but the 25% with persistent CDH still have a headache disability at 8-year follow-up and 12% have CDH, the majority diagnosed with chronic migraine. Factors predicting persistence of CDH into young adulthood include a history of migraine, early onset, longer duration than 2 years, and medication overuse. Of interest, only 5 (5%) subjects in this study used preventive agents, and neurology consultation was obtained by only 4%. Only 30% subjects used painkillers, the majority over-the-counter medications.
In an Editorial , Mack KJ and Hershey AD at the Mayo Clinic emphasize the variability of symptoms of CDH between patients and in an individual. CDH presents as severe intermittent migraine attacks, intermittent low severity headaches, continuous headache, or as a combination of these headache types. CDH affects 1 – 2% of middle-school children. A family history of migraine is common. Most patients are headache-free within 1 to 2 years. A small proportion has a continuing problem, usually an episodic migraine.