Introduction - Depression, through its conceptual and/or etiological frameworks, is a disease that exemplifies the new approaches developed in social epidemiology: biographical epidemiology and contextual epidemiology. The objective of this study is to propose hypotheses for understanding this illness based on the complementary nature of these two approaches. Its goal is to investigate an association between potentially traumatic life events in childhood and the onset of depression in adulthood, and to determine whether, after adjusting for individual characteristics associated with depression, differences persist depending on the type of neighborhood of residence. Methods - The SIRS (Health, Inequalities, and Social Disruptions) cohort has been tracking a random sample of 3,000 individuals representative of the French-speaking adult population of Paris and its inner suburbs since 2005. This analysis uses individual data collected through face-to-face interviews at enrollment, focusing in particular on the participants’ depressive symptoms as assessed using the Mini-Diag, life events, and social conditions during childhood. The socioeconomic type of the IRIS (Clusters for Statistical Information) area where the individuals reside was also taken into account. The analyses employ logistic and multilevel regression models. Results — After adjusting for the participants’ demographic and socioeconomic characteristics, several biographical events that occurred during childhood, as well as certain characteristics of family functioning, were found to be strongly and independently associated with depression on the day of the survey; notably having been a victim of sexual abuse or a witness to interpersonal violence between parents, as well as the fact that parents experienced long periods of unemployment or severe financial difficulties. Furthermore, after adjusting for these individual characteristics, depression remains more prevalent in neighborhoods classified as “sensitive urban areas.” Conclusion—Several childhood events and living conditions appear to be detrimental to mental health in adulthood, and regional disparities persist even after adjusting for these factors. These findings reignite the debate on approaches to prevention, education, and screening for depression. (R.A.)