The biological approach states that psychological disorders are physical illnesses, and that the cause may be one or more of the following: brain injury, infection, neurotransmitters or genetics.

Accidental brain damage can lead to psychological disorders. Some examples are, a degeneration or malformation of brain cells can cause memory loss often present in Alzheimer’s disease. Korsakoff’s syndrome occurs when alcohol and drugs damage part of the brain involved with memory. We are familiar with the idea that bacteria or viruses causing physical illnesses, e.g. flu or meningitis, however it seems that infection can also cause mental illnesses. For example, influenza has been linked to schizophrenia. Torrey found that the mothers of schizophrenic people had contacted a particular strain of influenza during pregnancy. The virus may enter the unborn child’s brain where it is dormant until puberty, when other hormones activate it, producing schizophrenic symptoms. Neurotransmitters are thought to be out of balance in the nervous systems id individuals with certain psychological disorders/ mental illnesses. Depression has been associated with decrease availability of serotonin, and has also been associated with higher than normal levels of the cortisol hormone. Images of the brain have measured the action of neurotransmitters and associated illness like depression, (Mann et al. 1996). Important new genetic research has highlighted the possibility that some people may be genetically at risk of developing mental disorders, specifically schizophrenia and bipolar depression, in order to investigate genetic links researchers carry out family twin and adoption studies. Zimbardo et al. suggested that at a ‘first degree relative’ (e.g. son or daughter) is 10% more likely to inherit the bipolar disorder r schizophrenia due to genetics than a ‘second degree relative’ (e.g.