Research on behaviorally defined childhood neuropsychiatric disorders such as autism and ADHD suggests that the elucidation of underlying genetic, neurobiological and environmental factors may be impeded by the etiological heterogeneity of individuals meeting current diagnostic criteria. Accordingly, child and adolescent psychiatry is in great need of biological markers and new methodology to improve our understanding of etiologically meaningful subgroups and the pathophysiology of childhood onset mental health disorders. In response to this challenge, an innovative research strategy was developed and promoted by the Candidate during the first five years of this Independent Research Award. This research strategy focuses on the multi-level scientific study of individuals with known or suspected homogenous genetic etiology for neuropsychiatric, cognitive and developmental dysfunction. The term "behavioral neurogenetics" was coined by the Candidate to represent this methodology. In this application, three primary objectives are described: (1) To apply behavioral neurogenetics research methods to specific pediatric disorders such as fragile X syndrome, Turner syndrome and velo-cardio- facial syndrome. Data will be obtained from genetic analyses, neuroimaging studies, assessment of neuroendocrinological status, neurobehavioral assessment, and environmental analysis; (2) To enhance the Candidate's repertoire of research-related skills and knowledge in specific areas including functional neuroimaging and the investigation of new groups of children with genetic etiologies for neuropsychiatric disability; and (3) To significantly increase the scope and rigor of pediatric mental health research training and clinical research at Stanford University. The information gained from this work will contribute to our fundamental knowledge of linkages among gene, environment, brain, and behavior in specific neurogenetic conditions, and increase our understanding of the pathogenesis of mental disorders in children from the general population. It is anticipated that funding of this award will have an impact on science through facilitation of the Candidate s own research, and the overall pediatric mental health research enterprise that will be implemented at Stanford over the next five years.