in the womb). For example, Torrey (2001) found that the mothers of many people with schizophrenia had contracted a particular strain of influenza during pregnancy. The virus may enter the unborn child’s brain, where it remains dormant until puberty, when other hormones may activate it, producing the symptoms of schizophrenia. The emergence of the medical model in the 18th century led to more humane treatment for mental patients. Until then mental illness was blamed on demons or on evil in the individual. The medical model offered a different source of blame – the illness, which was potentially treatable. However, more recent critics have claimed that the medical model is inhumane. Thomas Szasz (1972) argued that mental illnesses did not have a physical basis, therefore should not be thought of in the same way. He suggested that the concept of mental illness was ‘invented’ as a form of social control. The available evidence does not support a simple cause and effect link between mental illnesses such as schizophrenia and altered brain chemistry. For example, schizophrenia is commonly associated with an excess of the brain neurotransmitter dopamine. However, some studies of schizophrenic patients have shown reduced levels of dopamine in some brain tissues, meaning that there may be simultaneous excesses and deficiencies in different parts of the brain. There is no evidence that mental disorders are purely caused by genetic inheritance – concordance rates are never 100%. Gottersman and Shields (1976) reviewed the results of five studies of twins looking for concordance rates for schizophrenia. They found that in monozygotic twins (identical) there was a concordance rate of around 50%. If schizophrenia was entirely the product of genetic inheritance then this figure should be 100%. It is likely that, in the case of certain disorders, what individuals inherit is…