The broad, long-term objectives of this proposed project are to develop and test an integrative model of biological and psychosocial variables influencing the course of post-traumatic symptoms in children who have experienced acute injuries. It is hoped that the funding permitted by this grant application will contribute to the understanding of risk factors for Post-traumatic Stress Disorder (PTSD) in children who have experienced injuries and to advance knowledge regarding the way in which biological and psychosocial variables interact to produce this debilitating disorder. This project aims to develop a comprehensive understanding of variables influencing the course of post-traumatic symptoms in injured children in order to eventually enable the early identification of children 'at risk' for post-traumatic stress disorder and to develop effective interventions. Methodological strengths of this project include: 1) the evaluation of injured children shortly after the traumatic event, 2) the sequential assessment of subjects over an 18-month time course, 3) the integration of biological and psychosocial assessment and data analysis, and 4) the use of innovative techniques for analyzing longitudinal data. A bio-behavioral conceptual framework is used in order to understand how psychobiological and psychosocial variables may influence each other to lead to the symptoms of PTSD. ? ?