title: Excessive daytime sleepiness in young adults: a 20-year prospective community study.
abstract: OBJECTIVE
  Excessive daytime sleepiness (EDS) is a symptom with high clinical and public health importance because of its association with increased risk for accidents, decreased productivity, and impaired quality of life. Little information is available regarding the longitudinal course or clinical correlates of EDS. The aim of this study was to explore associations between self-reported EDS, sleep disorder symptoms, major depression, and anxiety in a longitudinal community study of young adults.
  
  
  METHODS
  A prospective single-age community study of young adults (Zurich Cohort Study) was conducted from 1978 through 1999. Information was derived from 6 interviews administered when participants (N = 591) were ages 20, 22, 27, 29, 34, and 40 years. Trained health professionals administered a semistructured interview for health habits and psychiatric and medical conditions. The presence of either or both of 2 symptoms-accidentally falling asleep or excessive need for sleep during the day-was used to establish the presence of EDS.
  
  
  RESULTS
  EDS was a common complaint among the study participants, with increasing prevalence with age. Cross-sectionally, EDS was associated with insomnia symptoms, nocturnal hypersomnia, anxiety disorders, somatization, and reduced quality of life. Longitudinally, impaired sleep quality, waking up too early, and anxiety were associated with later EDS. Conversely, EDS was not significantly associated with later anxiety or depressive disorders.
  
  
  CONCLUSIONS
  Insomnia symptoms and anxiety are associated with the subsequent occurrence of EDS. Although these findings do not demonstrate causality, insomnia and anxiety disorders are prevalent and treatable conditions, and our results may have important clinical implications for the prevention and treatment of EDS. Whether the results of this study are limited to populations with elevated levels of psychopathology remains to be tested.
authors.affiliation: Mood and Anxiety Disorders Program, Intramural Research Program, National Institutes of Health, National Institute of Mental Health, Bethesda, MD 20892, USA. g.hasler@bluewin.ch
authors.forename: Gregor
authors.initials: G
authors.lastname: Hasler
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Buysse
authors.forename: Alex
authors.initials: A
authors.lastname: Gamma
authors.forename: Vladeta
authors.initials: V
authors.lastname: Ajdacic
authors.forename: Dominique
authors.initials: D
authors.lastname: Eich
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
authors.forename: Jules
authors.initials: J
authors.lastname: Angst
mesh_terms: D000328:Adult; D000367:Age Factors; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003625:Data Collection / Q000706:statistics & numerical data; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010555:Personality Inventory; D015995:Prevalence; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D011795:Surveys and Questionnaires; D013557:Switzerland / Q000453:epidemiology