title: Prevalence of causes of insomnia in primary care: a cross-sectional study.
abstract: BACKGROUND
  As a result of a research interest in primary insomnia, the prevalence of other causes of insomnia in primary care must be ascertained. No source was found in the literature. It is also essential to know the epidemiology of the common causes of a condition to make  an accurate diagnosis in primary care.
  
  
  OBJECTIVE
  To determine the prevalence of causes of insomnia in primary care, as part of a method of identifying patients with primary insomnia.
  
  
  METHODS
  Cross-sectional study in three general practices in Auckland,  New Zealand.
  
  
  METHODS
  Consecutive patients from the waiting room were asked to complete a nine-page questionnaire on possible causes of insomnia.
  
  
  RESULTS
  In total, 1517 patients were approached and 955 completed the nine-page questionnaire (63%). Of the  41% (388) who reported difficulty with sleeping, primary insomnia occurred in 12% (45) of the population (95% confidence interval = 9% to 15%); 50% (195) had depression, 48% (185) had anxiety and 43% (165) had general (physical) health problems. Obstructive sleep apnoea occurred in 9% (34)  and delayed sleep phase disorder in 2% (7). Only primary insomnia and delayed sleep phase disorder are mutually exclusive; the others can co-exist.
  
  
  CONCLUSIONS
  This is the first description of the prevalence of causes of insomnia in primary care. It is hoped that the focus  on primary insomnia will result in more behavioural treatments and lower the use of hypnotics in primary care; it should also assist in the appropriate detection and treatment of other causes of insomnia in primary care.
authors.affiliation: Department of General Practice and Primary Health Care, University of Auckland, Auckland, New Zealand. b.arroll@auckland.ac.nz
authors.forename: Bruce
authors.initials: B
authors.lastname: Arroll
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernando
authors.forename: Karen
authors.initials: K
authors.lastname: Falloon
authors.forename: Felicity
authors.initials: F
authors.lastname: Goodyear-Smith
authors.forename: Chinthaka
authors.initials: C
authors.lastname: Samaranayake
authors.forename: Guy
authors.initials: G
authors.lastname: Warman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000453:epidemiology; D005260:Female; D058006:General Practice; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000209:etiology; D011795:Surveys and Questionnaires; D055815:Young Adult