The Zurich study--a prospective epidemiological study of depressive, neurotic and psychosomatic syndromes. I. Problem, methodology.

The purpose and methodology of a 4-year longitudinal study based on a cohort aged 20 years are presented. A two-stage procedure was chosen; in 1978, 2201 males and 2346 females, aged 19-20, were examined. This sample was representative of the respective age group in the Canton of Zurich. From high and low-scorers (SCL-90), 292 males and 299 females were randomly selected for interview and for a prospective study. Subsequent investigations were carried out by questionnaires and by a personal interview. The instruments chiefly consisted of a semi-structured interview (SPIKE), a clinical syndrome list (SL), a 90-item symptom check list (SCL-90R), a life-event-inventory, scales measuring coping behavior and dissimulation, and an extensive sociological interview dealing with sociodemographic characteristics and social adjustment. This paper gives an account of the methodological aspects of the study.