Schizophrenia: Genes and environment

The historical and genetic foundations of our current understanding of schi zophrenia are reviewed, as are the present and future directions for resear ch. Genetic epidemiological investigations, including family, twin, and ado ption studies have confirmed the contributions of genetic and environmental determinants of schizophrenia. For example, identical twins show average c oncordance rates of only 50%; rates of 100% would be expected on the basis of genetic equivalence alone, Genetic factors may cause errors in brain dev elopment and synaptic connections. A broad range of environmental component s may further damage the brain. Biological components may include pregnancy and delivery complications, such as intrauterine fetal hypoxia, infections , malnutrition. Primarily nonbiological components may include psychosocial stressors, such as residence in an urban area and dysfunctional family com munication. It is likely that the environmental factors interact with the g eneric liability in a negative manner to produce disorders in the schizophr enic spectrum. Genetic and environmental components of the disorder are exa mined, as well ns their interactions in producing either neurodevelopmental syndromes or schizophrenia itself: The implication of these findings for p revention and treatment are considered. Biol Psychiatry 2000;47:210-220 (C) 2000 Society of Biological Psychiatry.