The major aim of this study is to complete coding and carry out analyses of an extensive set of diagnostic, interview, and test data being collected on a large sample of schizophrenic and control adoptees and their respective biological and adoptive relatives. The sample is the Provincial subsample of a national sample of non-familial adoptions of schizophrenics compiled by Kety, Rosenthal, Wender, and Schulsinger over a period of two decades in Denmark -- a unique total national sample of particular value in investigating genetic and environmental contributions to etiology of schizophrenia. The probands for the sample are 42 pairs of schizophrenic and control adoptees placed for adoption in Danish provinces outside of Copenhagen and matched for age, sex, age at adoption, and socioeconomic status of the adoptive parents. The 582 biological and adoptive parents, siblings, and half-siblings of these adoptees have been identified, and over 90% of those alive and residing in Denmark have participated in an extensive psychiatric interview, including the SADS-L. DSM-III diagnoses, and other diagnostic and test evaluations, are made blind with respect to each other and to subjects' relationship to a schizophrenic or control proband. To elucidate the role of genetic and environmental factors in schizophrenia, the study will use this sample and several innovative research strategies to help: a) separate the influence of genetic and environmental factors, b) distinguish environmental factors that contribute to schizophrenia from those that are feedback effects of schizophrenics on their environments, c) contrast environments of schizophrenic and nonschizophrenic individuals who are likely to carry genes predisposing to schizophrenia, to help reveal genotype-environment interactions in schizophrenia. Several new methods of analysis have been developed, and will be applied to a number of variables that previous investigation has indicated may be of etiological relevance to schizophrenia. We will test specific hypotheses about measures of eye-tracking, thought disorder, communication deviance, platelet MAO, obstetrical complications, and their interactions. Results could significantly advance our knowledge of schizophrenia.