Bryne, Hodges, Rimmington, Best, Owens, & Johnston, 1999). It is also believed that events in a person’s environment trigger schizophrenia. Some studies have shown that influenza infection or improper nutrition during pregnancy and complications during birth may increase the risk that the baby will develop schizophrenia later in life. Many researchers believe schizophrenia is likely caused by a complex combination of gene and environmental factors. Certain people are born with a tendency to develop the disease, but the disease only appears if these people are exposed to unusual stresses or trauma. Nonetheless, most experts agree that symptoms are provoked by chemical disturbances of the brain function, but no mechanism is known. The view that mental disorders result from abnormalities of brain chemistry received the first experimental support during the 1940’s. Hallucinogens such as LSD , and later amphetamine and mescaline, were found to produce schizophrenia-like symptoms in healthy patients. Brain imaging techniques, such as magnetic resonance imaging (MRI) and positron-emission tomography (PET), have led researchers to discover specific structural abnormalities in the brains of people with schizophrenia (Lawrie et al., 1999). For example, people with chronic schizophrenia tend to have enlarged brain ventricles (cavities in the brain that contain cerebrospinal fluid). They also tend to have a smaller overall volume of brain tissue compared to mentally healthy people. Other people with schizophrenia show abnormally low activity in the frontal lobe of the brain, which governs abstract thought, planning, and judgement. There has also been evidence of other possible abnormalities in many other parts of the brain, including the temporal lobes, basal ganglia, thalamus, hippocampus, and superior temporal gyrus. These defects may partially explain the abnormal thoughts, perceptions, and behaviors that characterize schizophrenia....
