This is a revised proposal for a Scientist Development Award for Clinicians. Its major long-term objective is to enable the candidate to develop expertise in epidemiology and a working knowledge of neurovirology and neurodevelopment, so that he can independently conduct epidemiologic investigations of schizophrenia and prenatal exposures to viruses and other factors. The training plan will consist of: l) intensive coursework and seminars in epidemiology and biostatistics, sufficient to obtain an M.P.H. degree; 2) direct supervision by senior researchers in schizophrenia, epidemiology, and biostatistics; and 3) learning the essential principles of virology and neurodevelopment through direct supervision by established neurovirologists and developmental neuroanatomists, virological laboratory work, introductory coursework, and directed readings. The proposed research will serve as a vehicle for training in these areas, and seeks to rigorously and systematically determine whether prenatal exposure to specific infectious agents, folate deficiency, and other factors are associated with schizophrenia in adulthood. The research plan consists of: 1) an extension of our study of prenatal influenza and schizophrenia in Holland, which will examine whether urban vs. rural settings modify the effect of prenatal influenza exposure in schizophrenia, and whether misclassification of schizophrenia as affective disorders may have played a role in our findings; 2) epidemiologic studies of schizophrenia and prenatal exposure to 23 infectious diseases in Holland, which seeks to identify candidate viruses that will be tested in the seroepidemiologic studies; and 3) an unprecedented seroepidemiologic investigation of prenatal exposure to influenza, measles, and varicella-zoster virus in schizophrenia. In the later years of the award, the candidate will: l) investigate potential associations between schizophrenia and prenatal exposure to other candidate infectious agents, and to nutritional factors in the seroepidemiologic studies; and 2) pursue the implications of significant findings from the seroepidemiologic studies of infectious agents. This will be accomplished by attempting to characterize schizophrenic patients in whom exposure to prenatal infectious agents has been serologically documented, and by comparing them with respect to clinical characteristics, family history, and neurobiological parameters to schizophrenic patients in whom viral exposures have been ruled out.