title: Primary chronic daily headache and its subtypes in adolescents and adults.
abstract: OBJECTIVE
  To determine the relative frequency of chronic daily headache (CDH) subtypes in adolescents and to compare the distribution of CDH subtypes in adolescents and adults of various ages.
  
  
  METHODS
  Adolescents (13 to 17 years, n = 170) and adults (18 or older, n = 638) were recruited during the same time frame. CDH subtypes were classified according the criteria proposed by Silberstein and Lipton (1996) as transformed migraine (TM), chronic tension-type headache (CTTH), new daily persistent headache (NDPH), and hemicrania continua (HC).
  
  
  RESULTS
  Among adolescents and adults there were substantial differences in the distribution of CDH subtypes. The relative frequency of TM was lower in adolescents (68.8% vs 87.4%, p < 0.001), while NDPH (21.1% vs 10.8%, p < 0.001) and CTTH (10.1% vs 0.9%, p < 0.0001) were more common. HC (0 vs 0.9%, NS) was equally rare. The lower relative frequency of TM in adolescents was accounted for by TM with medication overuse (TM+), much more common in adults (28.2% vs 62.5%, p < 0.001). In fact, TM without medication overuse (TM-) was more common in adolescents (40.5% vs 24.9%, p < 0.001). The relative frequency of TM+ increased until the age of 50 years (p < 0.001).
  
  
  CONCLUSIONS
  In adolescents with CDH, TM usually develops without medication overuse. Adolescents with the early onset form of TM may develop the disorder in the absence of medication overuse because they are at increased biologic risk.
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine, 1165 Morris Park Avenue, Bronx, NY 10461, USA. mbigal@aecom.yu.edu
authors.forename: M E
authors.initials: ME
authors.lastname: Bigal
authors.forename: R B
authors.initials: RB
authors.lastname: Lipton
authors.forename: S J
authors.initials: SJ
authors.lastname: Tepper
authors.forename: A M
authors.initials: AM
authors.lastname: Rapoport
authors.forename: F D
authors.initials: FD
authors.lastname: Sheftell
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D005260:Female; D020773:Headache Disorders / Q000145:classification / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000453:epidemiology; D018710:Pain Clinics / Q000706:statistics & numerical data; D015995:Prevalence; D011795:Surveys and Questionnaires; D018781:Tension-Type Headache / Q000453:epidemiology