title: Prevalence of narcolepsy symptomatology and diagnosis in the European general population.
abstract: OBJECTIVE
  To determine the prevalence of narcolepsy in the general population of five European countries (target population 205,890,882 inhabitants).
  
  
  METHODS
  Overall, 18,980 randomly selected subjects were interviewed (participation rate 80.4%). These subjects were representative of the general population of the UK, Germany, Italy, Portugal, and Spain. They were interviewed by telephone using the Sleep-EVAL expert system, which provided narcolepsy diagnosis according to the International Classification of Sleep Disorders (ICSD).
  
  
  RESULTS
  Excessive daytime sleepiness was reported by 15% of the sample, with a higher prevalence in the UK and Germany. Napping two times or more in the same day was reported by 1.6% of the sample, with a significantly higher rate in Germany. Cataplexy (episodes of loss of muscle function related to a strong emotion), a cardinal symptom of narcolepsy, was found in 1.6% of the sample. An ICSD narcolepsy diagnosis was found in 0.047% of the sample: The narcolepsy was severe for 0.026% of the sample and moderate in 0.021%.
  
  
  CONCLUSIONS
  This is the first epidemiologic study that estimates the prevalence of narcolepsy in the general population of these five European countries. The disorder affects 47 individuals/100,000 inhabitants.
authors.affiliation: Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, CA 94305, USA. mrcohayon@aol.com
authors.forename: M M
authors.initials: MM
authors.lastname: Ohayon
authors.forename: R G
authors.initials: RG
authors.lastname: Priest
authors.forename: J
authors.initials: J
authors.lastname: Zulley
authors.forename: S
authors.initials: S
authors.lastname: Smirne
authors.forename: T
authors.initials: T
authors.lastname: Paiva
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002385:Cataplexy / Q000175:diagnosis / Q000453:epidemiology; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D007407:Interviews as Topic / Q000379:methods; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis* / Q000453:epidemiology*; D015995:Prevalence