Received: 17 July 2017 | Revised: 15 November 2017 | Accepted: 18 November 2017 DOI: 10.1002/dev.21600 RESEARCH ARTICLE An exploratory analysis of the joint contribution of HPA axis activation and motivation to early adolescent depressive symptoms Karen D. Rudolph 1 | Wendy Troop-Gordon 2 | Haina H. Modi 1 | Douglas A. Granger 3,4,5 1 University of Illinois, Urbana-Champaign, Urbana, Illinois 2 Auburn University, Auburn, Alabama 3 Institute for Interdisciplinary Salivary Bioscience Research, University of California, Irvine, California 4 Johns Hopkins University School of Medicine, School of Nursing, and Bloomberg School of Public Health, Baltimore, Maryland 5 Department of Psychology and Salivary Bioscience Laboratory, University of Nebraska at Lincoln, Lincoln, Nebraska Correspondence Karen D. Rudolph, Department of Psychology, University of Illinois, 603 E. Daniel St., Champaign, IL. Email: krudolph@illinois.edu Funding information University of Illinois; National Institute of Mental Health, Grant number: MH68444 Abstract This study examines the interactive contribution of the hypothalamic-pituitary-adrenal (HPA) axis and approach-avoidance motivation systems to longitudinal changes in depressive symptoms across the adolescent transition. In the summer prior to, or fall of, 4th grade, 132 youth (68 girls; 64 boys; M age = 9.46 years) participated in a social challenge task and reported on their depressive symptoms. In the winter of 6th grade, youth completed a semi-structured interview of depression and a self-report measure of approach-avoidance motivations. Analyses revealed two profiles of risk for adolescent depressive symptoms, with some gender differences: (1) excessive disengagement, reflected in HPA underactivation along with low approach motivation or high avoidance motivation; and (2) excessive engagement, reflected in HPA overactivation along with high approach motivation. This research highlights the importance of a multi-system perspective on development, suggesting that the implications of HPA dysregulation for depressive symptoms are contingent on adolescents’ tendencies toward approach versus avoidance. KEYWORDS adolescence, cortisol, depression, gender, motivation 1 | INTRODUCTION The transition to adolescence is a period of heightened risk for depression (Hankin & Abramson, 2001; Rudolph & Flynn, 2014), stemming, in part, from stage-specific perturbations in the arousal and motivation systems undergirding emotion and behavior. In particular, adolescence is marked by enhanced sensitivity of approach and avoidance systems combined with compromised regulation of arousal (Casey et al., 2010; Crone & Dahl, 2012; Ernst, 2014). Despite the growth of complex theoretical models emphasizing the intersection of multiple systems in determining the development of depression across the adolescent transition, most empirical research focuses on these systems in isolation and relies on concurrent designs. This approach limits our understanding of how systems intersect to predict the unfolding of depression across this stage. To address this gap, the present study used a longitudinal design tracking youth from 4th to 6th grade to examine the interactive contribution of arousal (activation of the hypothalamic- pituitary-adrenal [HPA] axis) and motivations (self-reported approach vs. avoidance) to adolescent depressive symptoms. Given evidence for elevated depression risk (Hankin & Abramson, 2001; Rudolph & Flynn, 2014) as well as stronger links between these risk factors and depression (Gunnar, Wewerka, Frenn, Long, & Griggs, 2009; Llewellyn & Rudolph, 2014; Natsuaki et al., 2009) in adolescent girls compared to boys, we examined gender differences in this joint risk for depression. Developmental Psychobiology. 2018;60:303–316. wileyonlinelibrary.com/journal/dev © 2018 Wiley Periodicals, Inc. | 303