title: The Zurich Study: participation patterns and Symptom Checklist 90-R scores in six interviews, 1979-99.
abstract: OBJECTIVE
  The Zurich study is a longitudinal study in psychiatric epidemiology that started in the late 1970s. The sixth interview in 1999 provides the basis to investigate and update the participation and drop-out patterns of the Zurich subjects.
  
  
  METHODS
  Aside from descriptive analyses, particular attention was paid to the Symptom Checklist 90-R (SCL-90-R), used initially to stratify the Zurich sample.
  
  
  RESULTS
  The initial proportions of high-scorers vs. low-scorers (two-thirds vs. one-third) have not changed significantly in the 367 subjects who participated in the 1999 interview. More detailed analyses indicate a selective and changing dependence of participation/drop-out on health status as measured by the SCL-90 R. In recent interviews drop-out has become more likely in subjects with extremely high SCL scores and in subjects with low SCL scores.
  
  
  CONCLUSIONS
  Drop-out in the Zurich Study is associated with extreme SCL scores.
authors.affiliation: Psychiatric University Hospital Zurich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Eich
authors.forename: V
authors.initials: V
authors.lastname: Ajdacic-Gross
authors.forename: M
authors.initials: M
authors.lastname: Condrau
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: A
authors.initials: A
authors.lastname: Gamma
authors.forename: J
authors.initials: J
authors.lastname: Angst
authors.forename: W
authors.initials: W
authors.lastname: Rössler
mesh_terms: D000328:Adult; D016021:Epidemiologic Studies; D005260:Female; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D010352:Patient Dropouts; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index; D013557:Switzerland / Q000453:epidemiology