The Zurich Study. XVI. Early antecedents of depression. A longitudinal prospective study on incidence in young adults.

The purpose of this study was to investigate antecedents of first incidence of major depressive disorder and recurrent brief depression with the help of a cohort of 20 year-old Swiss, who was interviewed four times up to age 30. Cases diagnosed as depressed at the third or fourth interview (age 28 or 30) were compared with never diagnosed controls for antecedents at the first and second interview (age 21 and 23). Besides retrospectively assessed childhood precursors, later depressives showed slight differences in their relationship to parents and friends and early symptoms of subclinical depression, persistent helplessness and a surplus of life events. These antecedents were mainly found in females. The most persistent antecedent of later depression for both sexes was a higher score than controls' on the SCL-90R ("negative affectivity"). Whether this finding signifies that proneness to the milder depressions in young adults is rooted in personality is subject to discussion.