Family and genetic studies on the relationship of schizophrenia to affective disorders

Schizophrenia is a genetically influenced disease with a broad and heteroge neous phenotype transmitted in families. Of particular interest is the fami lial-genetic relationship between schizophrenia and affective disorders. Ta king advantage of refined epidemiological methods, the dichotomy between bo th groups of disorders is not less consistently found than expected. Recent ly, linkage studies identified multiple candidate regions for susceptibilit y genes for each of both disorders. Several of these candidate regions for schizophrenia are overlapping with candidate regions for bipolar disorder. Thus, the hypothesis of an etiological dichotomy of schizophrenia and affec tive disorders faces a new challenge.