Do Scientists Know What Causes 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.

Genetic Influence and Schizophrenia
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.

Environmental "Schizophrenia Causes"
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.

Schizophrenia and the Brain
It is likely that an imbalance in the complex, interrelated chemical reactions of the brain plays a role in schizophrenia. Imbalances of the neurotransmitters dopamine and glutamate (and possibly others) are currently being studied. Neurotransmitters are substances that allow brain cells to communicate with one another. Basic knowledge about brain chemistry and its link to schizophrenia is expanding rapidly and is a promising area of research.

The brains of people with schizophrenia look a little different from the brains of people without it, but the differences are small. Sometimes, the fluid-filled cavities at the center of the brain, called ventricles, are larger in people with schizophrenia. Also, the overall gray matter volume is lower, and some areas of the brain have less or more metabolic activity than normal.

Microscopic studies of brain tissue after death have also revealed small changes in the distribution or characteristics of brain cells in people with schizophrenia. It appears that many of these changes occurred in the womb, because they are not accompanied by glial cells, which are always present when a brain injury occurs after birth. One theory suggests that problems during brain development lead to faulty connections that lie dormant until puberty. The brain undergoes major changes during puberty, and these changes could trigger psychotic symptoms.

The only way to answer these questions about the cause of schizophrenia is to conduct more research. Scientists throughout the world are studying schizophrenia and trying to develop new ways to prevent and treat this disorder. emedtv