title: Measuring depression in South Korea: validity and reliability of a brief questionnaire in the Korean Cancer Prevention Study.
abstract: OBJECTIVE
  To examine the validity and reliability of a new questionnaire for measuring depression in a South Korean population, and then to estimate the prevalence of depression in that country using this tool.
  
  
  METHODS
  In total, 742,600 individuals (123,725 women), aged 30-64 years at entry into the Korean Cancer Prevention Study, completed a depression symptom in 1992 (baseline enrollment) and again in 1994. We examined the concurrent validity of the depression questionnaire by relating data from it to known socio-demographic and behavioral correlates of depression; its predictive capacity by relating scores from the questionnaire to the occurrence of future hospitalization for depression; and the test-retest reliability by comparing scores from its administration in 1992 to those in 1994.
  
  
  RESULTS
  The prevalence of major depression was 7.5% in men and 10.0% in women. Factors significantly related to major depression were being younger (men), being female, not being married, of lower socioeconomic status, being a smoker, a heavy drinker, and not exercising regularly. Men (hazard ratio; 95% confidence interval: 2.0; 1.8, 2.2) and women (1.6; 1.3, 1.9) with questionnaire-ascertained depression experienced an elevated risk of hospitalization for the disorder during follow-up. The rates of agreement between responses to 1992 and 1994 surveys were 91.3% in men and 88.3% in women.
  
  
  CONCLUSIONS
  These findings imply validity of the instrument and support its use in future studies directed at links of depression with somatic disease endpoints.
  
  
  CONCLUSIONS
  The questions do not have a specified time frame of reference.
authors.affiliation: Department of Psychiatry, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hyoung Yoon
authors.initials: HY
authors.lastname: Chang
authors.forename: Yee-Jin
authors.initials: YJ
authors.lastname: Shin
authors.forename: G David
authors.initials: GD
authors.lastname: Batty
authors.forename: Dong-Koog
authors.initials: DK
authors.lastname: Son
authors.forename: Young Duk
authors.initials: YD
authors.lastname: Yun
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Jee
authors.forename: Yejin
authors.initials: Y
authors.lastname: Mok
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Samet
mesh_terms: D000328:Adult; D044466:Asian People; D003863:Depression / Q000453:epidemiology*; D003866:Depressive Disorder / Q000453:epidemiology*; D003865:Major Depressive Disorder / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D011795:Surveys and Questionnaires
keywords: Depression; Epidemiology; Prevalence; Questionnaire