The Zurich Study: participation patterns and Symptom Checklist 90-R scores in six interviews, 1979-99.
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.
Eich
D
D
Psychiatric University Hospital Zurich, Switzerland.
Ajdacic-Gross
V
V
Condrau
M
M
Huber
H
H
Gamma
A
A
Angst
J
J
Rössler
W
W
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