title: Insomnia symptoms, depressive symptoms, and suicide ideation in Japanese white-collar employees.
abstract: BACKGROUND
  Although poor sleep quality is the most common subjective complaint of workers and is a risk factor for depressive symptoms and suicide, researchers have not yet provided definitive links between insomnia symptoms, depressive symptoms, and suicide.
  
  
  OBJECTIVE
  In our mediation model, we hypothesized relationships among insomnia symptoms, depressive symptoms, and suicide ideation. The purpose here was to use structural equation modeling (SEM) to test our mediation model.
  
  
  METHODS
  Three hundred forty-three Japanese full-time white-collar workers completed the measures to assess insomnia symptoms, depressive symptoms, and suicide ideation over an approximately 3-month period.
  
  
  RESULTS
  A SEM analysis revealed that insomnia symptoms were positively and significantly associated with depressive symptoms, and depressive symptoms were positively and significantly associated with suicide ideation. Two tests showed a significant indirect effect of insomnia symptoms on suicide ideation through depressive symptoms. Thus, these results supported our mediation model.
  
  
  CONCLUSIONS
  We conclude that insomnia symptoms were positively associated with suicidal ideation, though this relation was accounted for by depressive symptoms in Japanese white-collar workers.
authors.affiliation: Department of Social Psychology, Toyo University, 5-28-20 Hakusan, Bunkyo-ku, Tokyo, 112-8606, Japan, mtsukasa@hotmail.com.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Kato
mesh_terms: D000328:Adult; D000368:Aged; D003863:Depression / Q000453:epidemiology*; D005260:Female; D015438:Health Behavior; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009790:Occupations / Q000145:classification*; D015279:Organizational Culture; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D012959:Socioeconomic Factors; D059020:Suicidal Ideation; D011795:Surveys and Questionnaires; D055815:Young Adult