Psychological Medicine (2008), 38: 581‐589 doi:10.1017/S0033291708002857 Early childhood adversity and adolescent depression: the mediating role of continued stress N. A. Hazel a1 , C. Hammen a1 c1 , P. A. Brennan a2 and J. Najman a3 a1 University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA a2 Emory University, Department of Psychology, Atlanta, GA, USA a3 University of Queensland, School of Public Health, Brisbane, Australia ABSTRACT Background: While various conceptualizations of the link between childhood adversity and later depression have been offered, most have not accounted for the possibility that early adversity predicts continuing stress proximal to depression onset. Thus, the present study tested the possible mediating role of recent stress in the association between early adversity and depression in late adolescence. Method: Study questions were examined in a longitudinal community sample of 705 youth who were contemporaneously assessed for early adversity exposure prior to age 5 years, chronic and episodic stress at age 15 years, and major depression prior to age 15 years and between 15 and 20 years. Results: Total youth stress burden at age 15 years mediated the effect of early adversity on depression between ages 15 and 20 years, and none of the observed relationships were moderated by onset of depression prior to age 15 years. Conclusions: These findings suggest that continued stress exposure proximal to depression onset largely accounts for the association between early adversity and depression in late adolescence. Intervention should thus focus on disrupting the continuity of stressful conditions across childhood and adolescence. Future studies of the neurobiological and psychosocial mechanisms of the link between early experiences and depression should explore whether the effects of early experiences are independent of continuing adversity proximal to depressive onset. Key Words: Depression; early adversity; stress Correspondence: c1 Address for correspondence: C. Hammen, Ph.D., Department of Psychology, University of California, Los Angeles, CA 90095, USA. (Email: hammen@psych.ucla.edu) INTRODUCTION Early childhood adversities and recent negative life events have been shown to be robust predictors of major depression in adolescents and adults (Kessler & Magee, 1993; Kessler et al. 1997; Mazure, 1998; Hammen, 2005; Garber, 2006), but little research has examined how the two sources of stress might be associated in their link to depression. One approach hypothesizes that childhood adversity alters neurobiological and psychosocial processes whereby individuals may be sensitized to the effects of recent stressful events, responding with depression at lower levels of stress (Hammen et al. 2000) or with greater reactivity to the effects of adult severe events (Heim et al. 2000, 2002;