Causes+of+Schizophrenia

Causes of schizophrenia.
Like the other mental illnesses discussed here, scientists are still working to determine what causes schizophrenia. Also like the other mental illnesses, genetic and environmental factors most likely interact to cause the disease. Several studies suggest that an imbalance of chemical neurotransmitter systems of the brain, including the dopamine, GABA, glutamate, and norepinephrine neurotransmitter systems, are involved in the development of schizophrenia.20, 36 Family, twin, and adoption studies support the idea that genetics plays an important role in the illness. For example, children of people with schizophrenia are 13 times more likely, and identical twins are 48 times more likely, to develop the illness than are people in the general population.44 Scientists continue to look at genes that may play a role in causing schizophrenia. One gene of interest to scientists who study schizophrenia codes for an enzyme that breaks down dopamine in the synapse.12 Investigations to confirm the role of this and other genes are ongoing. Imaging studies have revealed differences in brain structure and function in individuals with schizophrenia compared with control individuals. Brain imaging studies show that young people who have schizophrenia have structural differences in their brains compared with individuals who do not have schizophrenia. These changes include a reduced total volume of the **cerebrum** (the upper portion of the brain, which is divided into halves), a reduced amount of **gray matter** (the tissue that makes up a majority of the brain and consists mainly of neuron cell bodies and dendrites), enlarged brain ventricles (the cavities, or spaces, in the brain that are filled with cerebrospinal fluid), and other abnormalities.38, 39, 41 PET scans of identical twins have revealed that the twin with schizophrenia has lower brain activity in the frontal lobes (the front section of the cerebral lobes) than does the twin who does not have schizophrenia.47 One group of researchers used MRI to periodically scan the brains of teens with childhood-onset schizophrenia and an age-matched control group over a five-year period. They found that teens with schizophrenia lose four times the amount of neurons in a specific region of the brain that teens in the control group lose.

http://science.education.nih.gov/Supplements/Nih5/Mental/guide/info-mental-c.htm