We are examining psychiatric and health outcomes in a 5-year follow-up of 200 well-characterized, very high-risk, maltreated and non-maltreated children. Risk and protective factors, psychiatric outcomes, DNA, and physiological outcomes were initially captured when children were 3-5 years of age. Our longitudinal follow-up of this sample at child ages 9-11 includes gold-standard assessments of psychiatric outcomes, health outcomes, and pre-clinical indicators of malfunctioning in the metabolic, inflammatory, and endocrine systems. This is an ideal study in which to examine patterns of stability and change in the regulation of stress-sensitive genes over time. We will measure DNA methylation in this sample at multiple points in both early and middle childhood to tackle critical gaps in knowledge regarding the longitudinal course of epigenetic processes over time. Our longitudinal design allows us to consider the prospective development and onset of health conditions following maltreatment, and the potential critical role of methylation in the emergence of these conditions. Embedding the proposed research in the ongoing study will result in significant cost efficiency by capitalizing on the rich observational and pathophysiological data already being collected. We hypothesize that methylation will mediate the association of maltreatment and child 1) psychiatric outcomes, including mood, anxiety, and externalizing disorders, 2) the onset of health conditions including obesity, asthma, and allergic rhinitis, and 3) pre-clinical indicators of malfunctioning in the metabolic (blood pressure, anthropometrics), pulmonary (pulmonary function tests), and cognitive/affective (cognitive tasks) systems.