Mental disorders will be studied and analyzed with a view to determining the genetic components in their etiology. Schizophrenia, affective disorders as well as other disorders will be studied in multigeneration families. Where data collection has just started, both genetic and environmental aspects will be examined. Appropriate modifications to existing computer programs will be made to suit specific problems relating to each data set. These will be applied to the data already collected and those that are currently being gathered with the special purpose of identifying major genes, by segregation and linkage analyses between such genes and polymorphic markers in blood. This research will lead to a more complete understanding of the determinants involved in mental disorders studied, to more accurate genetic counseling and hence to increased possibilities for prevention and or early treatment.