scientists have long known that schizophrenia runs in families. it occurs in 1 percent of the general population but is seen in 10 percent of people with a first-degree relative (a parent brother or sister) with the disorder. people who have second-degree relatives (aunts uncles grandparents or cousins) with the disease also develop schizophrenia more often than the general population. the identical twin of a person with schizophrenia is most at risk with a 40 to 65 percent chance of developing the disorder. our genes are located on 23 pairs of chromosomes that are found in each cell. we inherit two copies of each gene one from each parent. several of these genes are thought to be associated with an increased risk of schizophrenia but scientists believe that each gene has a very small effect and is not responsible for causing the disease by itself. it is still not possible to predict who will develop the disease by looking at genetic material. although there is a genetic risk for schizophrenia it is not likely that genes alone are sufficient to cause the disorder. interactions between genes and the environment are thought to be necessary for schizophrenia to develop. many environmental factors have been suggested as risk factors such as exposure to viruses or malnutrition in the womb problems during birth and psychosocial factors like stressful environmental conditions.
can schizophrenia be inherited?