title: Validation of the Long-term Difficulties Inventory (LDI) and the List of Threatening Experiences (LTE) as measures of stress in epidemiological population-based cohort studies.
abstract: BACKGROUND
  Stress questionnaires are included in many epidemiological cohort studies but the psychometric characteristics of these questionnaires are largely unknown. The aim of this study was to describe these characteristics for two short questionnaires measuring the lifetime and past year occurrence of stress: the List of Threatening Events (LTE) as a measure of acute stress and the Long-term Difficulties Inventory (LDI) as a measure of chronic stress.
  
  
  METHODS
  This study was performed in a general population cohort consisting of 588 females (53.7%) and 506 males (46.3%), with a mean age of 53.5 years (s.d.=11.3 years). Respondents completed the LTE and the LDI for the past year, and for the age categories of 0-12, 13-18, 19-39, 40-60, and >60 years. They also completed questionnaires on perceived stress, psychological distress (the General Health Questionnaire, GHQ-12), anxiety and depression (the Symptom Checklist, SCL-8) and neuroticism (the Eysenck Personality Questionnaire - Revised Short Scale, EPQ-RSS-N). Approximately 2 years later, 976 respondents (89%) completed these questionnaires for a second time.
  
  
  RESULTS
  The stability of the retrospective reporting of long-term difficulties and life events was satisfactory: 0.7 for the lifetime LDI and 0.6 for the lifetime LTE scores. The construct validity of these lists is indicated by their positive associations with psychological distress, mental health problems and neuroticism.
  
  
  CONCLUSIONS
  This study in a large population-based sample shows that the LDI and LTE have sufficient validity and stability to include them in major epidemiological cohort studies.
authors.affiliation: Interdisciplinary Center for Psychiatric Epidemiology, University Medical Center Groningen, University of Groningen, The Netherlands. j.g.m.rosmalen@umcg.nl
authors.forename: J G M
authors.initials: JG
authors.lastname: Rosmalen
authors.forename: E H
authors.initials: EH
authors.lastname: Bos
authors.forename: P
authors.initials: P
authors.lastname: de Jonge
mesh_terms: D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control / Q000523:psychology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000517:prevention & control / Q000523:psychology; D008016:Life Change Events; D008297:Male; D008875:Middle Aged; D000075384:Neuroticism; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012307:Risk Factors; D011795:Surveys and Questionnaires