title: A 10-year trend of insomnia prevalence in the adult Norwegian population.
abstract: OBJECTIVE
  We aimed to investigate the 10-year trend in the prevalence of insomnia symptoms, insomnia cases, and use of hypnotic agents in the adult Norwegian population.
  
  
  METHODS
  Data from two representative surveys assessing identical insomnia symptoms in the adult population of Norway, one conducted in 1999-2000 (N=2001) and one conducted in 2009-2010 (N=2000), were compared.
  
  
  RESULTS
  Controlling for basic demographic variables, significant increases were found over the 10-year study period in the prevalence of sleep-onset insomnia from 13.1% to 15.2%, dissatisfaction with sleep from 8.2% to 13.6%, daytime impairment from 14.8% to 18.8%, Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) insomnia cases from 11.9% to 15.5%, and hypnotic agent use from 6.9% to 11.1%. No secular trend was found for maintenance insomnia or for early morning awakening insomnia. Across the two surveys, women reported a higher prevalence of insomnia than men. Age was positively associated with the prevalence of nocturnal sleep problems and use of hypnotic agents but was inversely associated with daytime impairment. Individuals with low socioeconomic status (SES) reported a higher prevalence of several insomnia symptoms.
  
  
  CONCLUSIONS
  Insomnia seems to be on the rise in the general adult population, which gives reason for concern. Prevention of insomnia and cost-effective interventions should receive higher priority in the future.
authors.affiliation: Department of Psychosocial Science, University of Bergen, P.O. Box 7807, N-5020 Bergen, Norway; Norwegian Competence Center for Sleep Disorders, Jonas Lies vei 65, 5021 Bergen, Norway. Electronic address: staale.pallesen@psysp.uib.no.
authors.forename: Ståle
authors.initials: S
authors.lastname: Pallesen
authors.affiliation: Department of Public Mental Health, Norwegian Institute of Public Health, Kalfarveien 31, 5018 Bergen, Norway; Uni Health, Uni Research Bergen, P.O. Box 7810, N-5020 Bergen, Norway; Department of Psychiatry, Helse Fonna HF, P.O. Box 2170, N-5504 Haugesund, Norway.
authors.forename: Børge
authors.initials: B
authors.lastname: Sivertsen
authors.affiliation: Norwegian Competence Center for Sleep Disorders, Jonas Lies vei 65, 5021 Bergen, Norway; Department of Clinical Psychology, University of Bergen, P.O. Box 7807, N-5020 Bergen, Norway.
authors.forename: Inger Hilde
authors.initials: IH
authors.lastname: Nordhus
authors.affiliation: Norwegian Competence Center for Sleep Disorders, Jonas Lies vei 65, 5021 Bergen, Norway; Department of Public Health and Primary Health Care, University of Bergen, P.O. Box 7804, N-5020 Bergen, Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Bjorvatn
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D012737:Sex Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D006993:Hypnotics and Sedatives
keywords: Epidemiology; Insomnia; Prevalence; Secular; Sleep; Trend