Depression is one of the most common mental disorders among adolescents and has many negative consequences including impaired functioning and risk for future problems, (e.g., poor school performance, impaired relationships, substance abuse, and suicide). Mental health problems in youth often go unrecognized, and, even when they are recognized, most do not receive any treatment. Information on the burden of youth depression could show health system and public health policymakers the importance of teen depression as a health issue--they need accurate information to set priorities and fund programs to encourage youth depression treatment. Public health policymakers are increasingly using measures of health-related quality of life (HRQL) to compare the burden of disease between health conditions and HRQL is especially important in illnesses such as depression, where traditional measures of disease burden, such as mortality and morbidity, do not adequately capture the impact of the illness. Measures that rate the value of different health states, such as utility-based HRQL measures, are particularly helpful in demonstrating the burden of disease, analyzing the cost-effectiveness of new interventions, and setting priorities for clinical and reimbursement policies. No studies that have examined the use of utility-based HRQL measures in youth with depressive disorder. Our ultimate aim is to develop recommendations and guidelines for the assessment of HRQL in youth depression studies and clinical policymaking. This study will extend the understanding of HRQL in teens with depression by completing the following specific aims. First, we will evaluate the cross-sectional validity and reliability of several widely-used generic health status and utility-based HRQL measures in teens. Second, we will examine the sensitivity of the HRQL instruments in detecting clinically meaningful depression symptom change over 12 weeks following depression diagnosis. PUBLIC HEALTH RELEVANCE: Depression in teens is common and disabling. Currently available measures of the burden of depression in teens, such as symptom ratings, do not capture the full impact of depression on teens'lives. Improved measurement of the impact of depression on teen's quality of life would aid in evaluating new treatments and in setting public health policies to address teen depression.