title: Nighttime insomnia symptoms and perceived health in the America Insomnia Survey (AIS).
abstract: OBJECTIVE
  To explore the distribution of the 4 cardinal nighttime symptoms of insomnia-difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), and nonrestorative sleep (NRS)-in a national sample of health plan members and the associations of these nighttime symptoms with sociodemographics, comorbidity, and perceived health.
  
  
  METHODS
  Cross-sectional telephone survey of 6,791 adult respondents.
  
  
  METHODS
  None.
  
  
  RESULTS
  Current insomnia was assessed using the Brief Insomnia Questionnaire (BIQ)-a fully structured validated scale generating diagnoses of insomnia using DSM-IV-TR, ICD-10, and RDC/ICSD-2 inclusion criteria. DMS (61.0%) and EMA (52.2%) were more prevalent than DIS (37.7%) and NRS (25.2%) among respondents with insomnia. Sociodemographic correlates varied significantly across the 4 symptoms. All 4 nighttime symptoms were significantly related to a wide range of comorbid physical and mental conditions. All 4 also significantly predicted decrements in perceived health both in the total sample and among respondents with insomnia after adjusting for comorbid physical and mental conditions. Joint associations of the 4 symptoms predicting perceived health were additive and related to daytime distress/impairment. Individual-level associations were strongest for NRS. At the societal level, though, where both prevalence and strength of individual-level associations were taken into consideration, DMS had the strongest associations.
  
  
  CONCLUSIONS
  The extent to which nighttime insomnia symptoms are stable over time requires future long-term longitudinal study. Within the context of this limitation, the results suggest that core nighttime symptoms are associated with different patterns of risk and perceived health and that symptom-based subtyping might have value.
authors.affiliation: Sleep Medicine and Research Center, St. Luke’s Hospital, St. Louis, MO, USA.
authors.forename: James K
authors.initials: JK
authors.lastname: Walsh
authors.forename: Catherine
authors.initials: C
authors.lastname: Coulouvrat
authors.forename: Goeran
authors.initials: G
authors.lastname: Hajak
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Lakoma
authors.forename: Maria
authors.initials: M
authors.lastname: Petukhova
authors.forename: Thomas
authors.initials: T
authors.lastname: Roth
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Sampson
authors.forename: Victoria
authors.initials: V
authors.lastname: Shahly
authors.forename: Alicia
authors.initials: A
authors.lastname: Shillington
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Stephenson
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Kessler
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000569:Americas / Q000453:epidemiology; D001294:Attitude to Health; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006306:Health Surveys / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D055815:Young Adult