Childhood adversity, gender and depression over the life-course.

BACKGROUND: Full investigation of hypotheses concerning early risk factors and episodes of depression in adult life requires consideration of the separate risks of first onset and of recurrent episodes. This paper is based upon such an investigation.
METHODS: A sample of participants in a large-scale population study (n=3491) provided information through retrospective assessment of lifetime history of (putative) major depressive disorder and of their adverse experiences in childhood. A statistical model based on Poisson regression, that combined both the (survival) distribution of first onset times with the subsequent rate of episode recurrence was specified to permit investigation of the gender difference in lifetime depression and the influence of childhood adversities on adult depression.
RESULTS: A gender difference (with women at increased risk) was revealed for first onsets of depression only and was found to decrease with increasing age, being no longer apparent in those aged over 50. Experience either of a frightening event or of physical abuse in childhood was associated with an increased risk of first onset in younger adults (those aged < or =30). LIMITATIONS: The method of data collection used in this study warrants some caution in the interpretation of substantive findings.
CONCLUSIONS: The relationships revealed concerning the risk for early and for late first onset and the risk of recurrence suggest different causal pathways underlying the associations between risk factors experienced early in life and depression in adulthood. Analyses that take full account of episode history can aid understanding of the origins of depression in adulthood.