Considerable evidence has accumulated during the past thirty years which suggests that "perinatal complications", broadly defined, may be considered as one of the major known risk factors for a variety of psychiatric and neurologic disorders. Further investigation is required to support this claim, to further clarify the definition of risk and to quantify the magnitude of risk for specific disorders. Research in this area could result in the early identification of individuals at risk for subsequent psychiatric disorder and the implementation of preventive measures. We are proposing to complete a twenty-five year prospective study of the association between perinatal complications and psychiatric disorders. We will select a sample of 500 births with perinatal complications (prolonged fetal hypoxia, non-hypoxic complications and prematurity) and a matched control sample of 500 normal births from the Providence cohort of the National Collaborative Perinatal Project (NCPP) who were assessed at age seven. The mothers of these subjects were monitored systematically during pregnancy, and the children were evaluated at birth and throughout the first seven years of life on a wide range of neurological, cognitive, developmental and behavioral measures. Using follow-up methods tested and refined through two years of pilot work, we will contact these subjects (now ages 20-26) and administer the Diagnostic Interview Schedule, the Wechsler Adult Intelligence Scale and other instruments designed to gather psychiatric, psychosocial and neuropsychological outcome data. Quantitative estimates of the risk for various forms of psychiatric disorder will be obtained for a number of previously suggested risk conditions, including "perinatal complications", "prolonged fetal hypoxia", "non-hypoxic complications", "prematurity" and a range of additional variables contained in the baseline NCPP data set. The primary psychiatric disorders we plan to study are alcohol abuse and dependence, drug abuse and dependence, antisocial personality disorder, affective disorders, and minimal brain dysfunction. In addition to the quantification of the magnitude of risk associated with these risk conditions, our analyses will investigate potential etiologic mechanisms which have been proposed to account for the association between perinatal events and psychiatric outcomes.