No single factor has been found to cause schizophrenia. However, genetic and environmental factors are thought to play a role in the development of this disorder. Ongoing research in these areas aims to help scientists develop new ways to prevent and treat schizophrenia.
At this time, researchers have not pinpointed a specific schizophrenia cause. But, as is the case for many other illnesses, it is believed to result from a combination of environmental and genetic factors.
While genetics are not an exact cause, genes are thought to play a role in a person's risk of developing schizophrenia.
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 schizophrenia. 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, having a 40 to 65 percent chance of developing the condition.
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 currently believe that each gene has a small effect and that no single gene is the schizophrenia cause by itself. It is still not possible to predict who will develop the disease simply by looking at a person's genetic material.
So, although there is a genetic risk for schizophrenia, genes are unlikely to cause the disease on their own. It is believed that interactions between genes and the environment are necessary for schizophrenia to develop.
Many environmental factors have been suggested as risk factors for schizophrenia, such as:
- Exposure to viruses
- Malnutrition in the womb
- Problems during birth
- Psychosocial factors, like stressful environmental conditions.