PROJECT SUMMARY/ABSTRACT One-fifth of adolescents report a lifetime prevalence of depression and as many as one-fourth of adolescents report current use of alcohol and drugs. The proposed project will investigate a novel risk for depression and substance use and lower well-being during adolescence. Specifically, we will examine how adolescents' value and regulation of positive affect (PA) may hinder their adjustment and put them at risk for depression and substance use. Our premise is based on existing work an excessive valuing of positive affect to lower well- being and depressive symptoms. We also will examine how adolescents' motives to pursue PA may lead to substance use, which is crucial in adolescents given their increased freedom coupled with an increased propensity for reward-seeking or sensation-seeking behavior. Further, we will investigate how these values and pursuits of PA are socialized by parents. The project addresses the following aims: (1) investigate how adolescents' beliefs about PA predict negative outcomes; and (2) investigate associations among parents' beliefs about PA (their own and their child's) and the adolescents' beliefs about their PA. Upon completion of the study, we will provide valuable information about the development of psychopathology in adolescents, and identify new points of intervention via our investigation of the antecedents of maladaptive views of PA. Data will be collected from 280 adolescents and at least one of their parents. Parents and adolescents will complete a single in-person session in a laboratory or a home visit and two sets of surveys at 6 and 12 months following the initial session. Adolescents will complete surveys assessing the excessive value of PA, their pursuit of PA, depressive symptoms, well-being, and substance use. Covariates and potential moderators for Aim 1 will include traditional risk factors of depression and substance use (attribution style, gender, pubertal status, using drugs to cope, and impulsivity). Parents will complete similar measures about themselves and their children (the excessive value of PA, their pursuit of PA, as well as how much they value children's PA, and encourage them to upregulate it) and similar outcomes measures (e.g., depressive symptoms, well-being, substance use). Hypotheses for both aims will be analyzed with structural equation modeling. This study is innovative in its focus on PA as an influence on the development of psychopathology in a counter-intuitive manner (more is not necessarily better), and its application of emotion regulation theories to understand how emotion-related beliefs develop and can affect antecedent emotion regulation (i.e., the pursuit of PA) in healthy and unhealthy ways. Overall, the project offers a wealth of novel data, the potential for substantial training graduate and undergraduate students on this research project, and significant contributions to identify risks for depression, substance use, and poorer well-being in youth, thereby opening new pathways to prevention.