The overall goal of this proposal is to advance knowledge on the development of depression in children and adolescents by investigating biased attention to emotional stimuli as an intermediate trait, or endophenotype, for depression. Elucidating novel endophenotypes in youth will help to increase knowledge on developmental pathways to depression initiated by genetic vulnerabilities. Specifically, adult findings suggest that biased attention to emotion may be an endophenotype between genetic markers (e.g., serotonin transporter gene) and depression (Beevers, Gibb, McGeary, &Miller, 2007;Beevers, Wells, Ellis, &McGeary, 2009). Yet, no study to date has examined information processing of emotion as an endophenotype among youth. Furthermore, the study of the development of depression among youth is especially important given that adolescent-onset depression is associated with a 2-7 times increased likelihood of recurrence in adulthood (Rutter, Kim-Cohen, &Maughan, 2006). Therefore, to inform prevention efforts it is important to predict adolescent-onset depression before recurrent episodes occur. The study of developmental pathways to depression is consistent with the mission of the National Institute of Mental Health to understand trajectories of mental illness that can help determine when, where, and how to intervene as well as Director of NIMH Dr. Thomas Insel and colleagues'(2010) research domain criteria (RDoC) regarding the need for identifying biosignatures of mental illness utilizing data from genetics and clinically relevant circuitry-behavior models (e.g., attention bias to emotion). In addition, the proposed project will target the NIMH Division of Developmental Translational Research areas of high priority by 1) identifying behavioral phenotypes reflecting dimensional processes (i.e. attention to emotional stimuli) that will help to discover underlying genetic vulnerabilities, 2) testing a model that incorporates genetics and individual behavioral characteristics in the development of depression, and 3) employing a longitudinal design to examine pathways for depression and trajectories of increasing depression. Additionally, this proposal seeks to address important gaps in the literature on attention bias as an endophenotype of depression by employing a multi-method, multi-informant, and multi-wave design to investigate the long-term effects of possessing this endophenotype by assessing depression diagnoses and symptoms among 682 3rd, 6th, and 9th graders across 7 waves of data with regular follow-ups over a period of 18 months. Moreover, the proposed research will employ strong methodology to assess the potential endophenotype of biased attention to emotional faces by utilizing an objective measure of biased attention via a computer based information processing task. Finally, the research will examine carefully selected and theoretically motivated candidate genes: the serotonin transporter gene (5-HTTLPR), catechol-o- methyl-transferase gene (COMT), and dopamine D2 receptor gene (DRD2). The research will test clear a priori hypotheses about the developmental pathways through which candidate genes may influence depression.
The World Health Organization states that depression accounts for the greatest proportion of disease burden attributed to non-fatal illnesses (Utsun &Chatterji, 2001), and many individuals experience their first clinically significant depression during adolescence (Hankin et al., 1998). Furthermore, the study of the development of depression during adolescence is especially important given that adolescent-onset depression is associated with a 2-7 times increased likelihood of recurrence in adulthood (Rutter, Kim-Cohen, &Maughan, 2006). Therefore, the proposed research aims to study developmental pathways to depression among youth to inform prevention efforts before recurrent episodes occur.