title: Using difficulty resuming sleep to define nocturnal awakenings.
abstract: OBJECTIVE
  Nocturnal awakenings are one of the most prevalent sleep disturbances in the general population. Little is known, however, about the frequency of these episodes and how difficulty resuming sleep once awakened affects subjective sleep quality and quantity.
  
  
  METHODS
  This is a cross-sectional telephone study with a representative sample consisting of 8937 non-institutionalized individuals aged 18 or over living in Texas, New York and California. The interviews included questions on sleeping habits, health, sleep and mental disorders. Nocturnal awakenings were evaluated according to their frequency per week and per night, as well as their duration.
  
  
  RESULTS
  A total of 35.5% of the sample reported awakening at least three nights per week. Of this 35.5%, 43% (15.2% of the total sample) reported difficulty resuming sleep once awakened. More than 80% of subjects with insomnia symptoms (difficulty initiating or maintaining sleep or non-restorative sleep) also had nocturnal awakenings. Difficulty resuming sleep was associated with subjective shorter sleep duration, poorer sleep quality, greater daytime impairment, greater consultations for sleep disturbances and greater likelihood of receiving a sleep medication.
  
  
  CONCLUSIONS
  Nocturnal awakenings disrupt the sleep of about one-third of the general population. Using difficulty resuming sleep identifies individuals with significant daytime impairment who are most likely to seek medical help for their sleep disturbances. In the absence of other insomnia symptoms, nocturnal awakenings alone are unlikely to be associated with daytime impairments.
authors.affiliation: Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Stanford, CA 94303, USA. mohayon@stanford.edu
authors.forename: Maurice M
authors.initials: MM
authors.lastname: Ohayon
authors.forename: Andrew
authors.initials: A
authors.lastname: Krystal
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Roehrs
authors.forename: Thomas
authors.initials: T
authors.lastname: Roth
authors.forename: Michael V
authors.initials: MV
authors.lastname: Vitiello
mesh_terms: D000367:Age Factors; D000368:Aged; D002140:California / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D016017:Odds Ratio; D015995:Prevalence; D012737:Sex Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D013781:Texas / Q000453:epidemiology
chemical_list: D006993:Hypnotics and Sedatives