This Mentored Patient-Oriented Research Career Development Award is focused on elucidating neural and psychosocial mechanisms of eating disorders in adolescence. The research and training plans are designed to prepare the investigator to conducted independent research in adolescent eating disorders through training in biobehavioral and psychosocial mechanisms and sophisticated methods for their assessment. Eating disorders are characterized by high rates of physical and psychiatric morbidity, and adolescence is a developmental phase in which eating disorders commonly emerge. Negative self-related schema (i.e., low self-esteem) and poor social functioning are hypothesized to contribute to the onset and/or maintenance of eating disorders by promoting maladaptive restrictive eating and recurrent binge eating. However, few studies have investigated these constructs outside the self-report domain, and examinations of direct associations with eating disorder behavior are limited. Thus, the role of self-related schema and poor social functioning as eating disorder etiologic and maintenance factors, as well as their utility as treatment targets, remain key empirical gaps. This K23 aims to address these gaps by testing associations among negative self-related schema, social functioning, and eating disorder behavior across units of analysis including neurophysiological activity, phenotypes, and real-time passive monitoring. Participants will include female adolescents aged 14-17 years with maladaptive restrictive eating (defined by a diagnosis of AN, n = 30), recurrent binge eating (defined as a diagnosis of bulimia nervosa (BN) or binge eating disorder (BED), n = 30), and healthy controls (n = 30). At baseline, adolescents will complete a self-referential encoding task while electroencephalography data are acquired to probe behavioral and neurophysiological processes of self-related schema. To probe real-time social processes, we will leverage smartphone technology and use a passive sensing application over a 6- month period to continuously measure key aspects of social functioning—size of social network, frequency of interactions, and negative content of interactions. Adolescents in the eating disorder groups will complete ecological momentary assessment 1 week/month for six-months to assess the frequency and intensity of maladaptive restrictive and binge eating in the natural environment. The following aims will be addressed: First, we will compare self-related schema and social functioning between adolescents with an eating disorder and healthy controls (Aim 1). Second, we will test the associations between self-related schema and social functioning with the frequency and intensity of eating disorder behavior over 6-months (Aim 2). Last, we will test the interaction between negative self-related schema and social functioning to predict eating disorder behavior. The current project will elucidate whether self-related schema and social functioning distin...