The biological model compares abnormal behaviour with a disease. It assumes that all mental illnesses have a physiological cause related to the physical structure and brain. Doctors diagnose mental illness using well-established criteria. Psychiatrists also use diagnostic manuals for mental illness and compare symptoms with set classifications of illnesses. According to the biological model, mental illness is caused by one or more of the following factors; genetic inheritance, bio-chemistry and infection. The reason why genetic inheritance could be a possible cause for mental illness is due to the assumption that people have a genetic disposition to certain psychological disorders. For example, Kendler et al found relatives of schizophrenics were 18 times more likely to develop the illness than a matched control group. Bio-chemistry is also a factor that is considered as it is thought that chemical imbalances in the brain may be involved in certain mental illnesses. Neurotransmitters play an important part in behaviour. For example, an excess of dopamine has been detected in the brains of schizophrenics. This finding, however, has been assumed due to correlation which does not prove cause and effect. Infection is also thought to be a factor which could potentially cause mental illness as research suggests that some mental illnesses, such as schizophrenia, may be related to exposure to certain viruses in the womb. For example, Torrey found that the mothers of many people with schizophrenia had contracted a particular strain of influenza during pregnancy. It is supposed that the virus may have entered the unborn child’s brain and remained dormant there until puberty, when other hormones may have activated it.
The biological model is supported by research and has been tested. This shows us that it is reliable and scientific. Also, the increased use of brain scans and post mortems adds to the growing body of