The interplay of familial depression liability and adverse life events in predicting the first onset of depression during a ten-year follow-up

Aim: To explore the interaction and correlation effects between familial depression liability and adverse (separation and traumatic) events in predicting the first onset of a major depressive episode (MDE) in a ten-years-prospective-longitudinal community survey. Methods: Analyses are based on 1982 subjects (aged 14-24 years at baseline) without baseline MDE who participated during the whole study period of ten years and for whom diagnostic information about psychopathology in both parents was available. Information on familial depression was collected from family history data and diagnostic interviews with parents. For assessment the M-CIDI according to DSM-IV algorithms was used. Results: Adverse events predicted a substantially increased incidence of MDE among respondents with familial liability, but not in those without. There was a significant interaction between familial liability and traumatic events (e.g. violence, rape/abuse, serious accident) with the strongest effect for the number of severe trauma (Risk Difference=11.3%; 95%CI=3.55-19.15). Associations with familial liability were most pronounced for separation events (parental divorce/death of a parent). Conclusions: Adverse events are particularly pathogenic in individuals with familial liability. The involvement of interactions and correlations between familial liability and adversity might depend on type, severity, and number of events. Both processes are suggested to be concomitant rather than exclusive.