Schizophrenia is a multifaceted disorder that manifests by both genetic and environmental factors. A plethora of twin and adoption studies suggest major genetic influences on the pathogenesis of schizophrenia; however, a MZ concordance of 50% also suggests environmental factors (Cardno et al., 1999). [Note, a concordance of 100%, or absolute probability that both "identical" twins are afflicted or not, would suggest a single gene disorder, as in sickle cell anemia and cystic fibrosis.] These family studies reveal that schizophrenia is a complex genetic disorder, akin to diabetes and most cancers, where not but multiple causative genes contribute to susceptibility — a polygenetic disease. Moreover, there are presumably environmental factors that contribute to the onset. Read more →