Background: Daily-life stress sensitivity is associated with depression, but prospective data are lacking.
Aims: To examine associations between baseline ecological daily-life stress sensitivity and later depression, and to identify genetic and non-genetic factors moderating the transition from stress sensitivity to depression.
Method: Daily-life stress sensitivity was assessed at baseline in twins (n = 502). One baseline and four follow-up measurements of depressive symptoms and negative life events were collected, as well as interview-based diagnoses at baseline and last follow-up. Hypothesised genetic markers were determined.
Results: Baseline stress sensitivity was associated with increased depressive symptoms at follow-up and risk of major depressive disorder. Both genetic liability and major life events moderated the probability of transition from stress sensitivity to depression.
Conclusions: Onset of depression is attributable to pre-onset ecological measurements of stress sensitivity, particularly where genetic liability is high and individuals have reached a stage where the influence of competing environmental causes is low.