Abstract Individual differences in brain structure, including cortical morphology and the white matter connectome are associated with risk for psychiatric disorders. The first year of life is a period of rapid and dynamic structural and functional brain development and new data from our cohort suggests that a large portion of individual differences in brain structure in 10 and 12 year olds is already present in the first year or two of life. Early adolescence and puberty is the second major period of postnatal brain development, characterized by dynamic structural and functional brain maturation and reorganization, and emerging risk for psychiatric disorders, though it is not known how this period of development contributes to individual differences in brain structure and risk. The UNC Early Brain Development Study is a unique and innovative longitudinal study that has followed children, enrolled prenatally, with imaging and cognitive/behavioral assessments at birth, 1, 2, 4, 6, 8 and 10 years. 482 children from this cohort are now reaching adolescence, and we propose to follow these children at 12, 14 and 16 years of age. MRIs, including structural, diffusion tensor, and resting state functional imaging, will be performed. Cognitive and behavioral development will be assessed, with a focus on the phenotypes of executive function, attention, and anxiety, consistent with RDoC constructs important for psychiatric disorder risk. We will determine how adolescent brain development contributes to individual differences in relation to early childhood development and whether the white matter connectome is a useful early imaging biomarker. Knowledge gained in this study will improve our basic understanding of human brain development, and ultimately inform early intervention strategies that prevent or mitigate risk and illness severity. Relevance New knowledge gained in this study will provide a dramatically improved framework for understanding childhood brain development and its relationship to cognitive and behavioral outcomes in adolescence, and to risk for subsequent psychiatric disorders.