PROJECT SUMMARY/ABSTRACT Adolescence is a developmental period characterized by increased reward responsivity; it also reflects a high- risk period for the emergence of depression. Adolescence represents an ideal time to identify risk factors and refine the specificity of models of the development and pathophysiology of depression. Most research elucidating the role of reward processing during development and depression has studied reward liking, as indexed by the reward positivity (RewP) event-related brain potential (ERP); however, previous work indicates that reward processing may be better conceptualized in terms of multiple aspects beyond liking, including wanting—a process also impaired in depression. Using a novel effort-reward task developed by our group, the primary goal the research is to determine the impact of effort expenditure on multiple reward processing stages (i.e., effort- based reward processing) using several ERPs in a well-characterized adolescent sample. In the proposed study, 150 adolescents (aged 14 to 17) and their caregivers from the greater Tallahassee, FL community will complete self-report questionnaires and clinical interviews as part of three-year follow-up visit of an ongoing longitudinal study. Adolescents will complete the effort-doors task to elicit ERPs linked to multiple reward processing stages: effort complete, reward anticipation, and sensitivity to reward receipt. Consistent with developmental research, we predict age to be associated with a larger impact of effort on multiple stages of reward processing, such that older adolescents will exhibit larger ERPs across multiple stages of reward processing following high effort (Aim 1). In terms of depression, we predict that increased depressive symptoms will relate to blunted effort-based reward processing, such that the impact of effort on multiple reward processing stages will be potentiated among adolescents with increased depressive symptoms (Aim 2). A secondary goal of this research is to elucidate diathesis-stress models in relation to depression. The proposed study will also examine whether lifetime stress exposure, as measured using the Adolescent Stress and Adversity Inventory, impacts ERPs linked to specific or multiple stages of reward processing–and whether lifetime stress exposure interacts with specific reward processing stages to explain emerging symptoms of depression. We predict that lifetime stress exposure will potentiate the impact of effort on reward processing following high effort completion (Aim 3). We also predict that increased lifetime stress exposure will interact with deficits in multiple stages of reward processing to explain increased depressive symptoms among adolescents (Aim 4). The proposed study will provide expertise in developmental psychopathology, broaden knowledge of multiple reward-related processes and their measurement, and provide training in clinical interviewing and life stress assessment in the context of emergin...