Schizophrenia Hereditary?
People who have a relative with schizophrenia have a greater risk of developing the disorder than the general population. For example, if you have an identical twin with schizophrenia, your chance of having schizophrenia is 50% in contrast to the 1% chance for the public at large. Adoption studies have shown that biological relatives have an increased risk for schizophrenia whereas adoptive relatives have no increased risk. Such studies clearly point to the contribution of a genetic component in the development of schizophrenia. Nongenetic factors can also influence the development of schizophrenia, as evidenced by the fact that, even in people with identical genes (i.e., monozygotic twins), only in about 50% of the cases are both twins ill.
