Abnormality is caused by physical factors.
The biological model assumes that all mental disorders are related to some change in the body. Mental disorders are like physical disorders i.e. they are illnesses. Such changes or illnesses may be caused by one of four possible factors; genes, biochemistry and neuronatomy.
Abnormalities in the brain anatomy or chemistry are sometimes the result of genetic inheritance, and so are passed parent to child. By studying identical twins, to see if one twin has the disorder, does the other? There are low concordance rates for some mental disorders (e.g. phobias) but relatively high concordance rates for others (e.g. schizophrenia). Many of the genes responsible for abnormal behaviours are the product of evolutionary adaptations in our ancestors.Gottesman reviewed the results of five studies of twins, looking for concordance rates for schizophrenia. They found that in mono-zygotic (identical) there was a concordance of around 50%.
Human or inhumane?
Recent critics have claimed that the medical model is inhumane. Thomas Szas 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.
Cause and effect?
The available evidence does not support a simple cause and effect link between mental illnesses such as schizophrenia and altered brain chemistry.
Experiments- If patients fare better when given a drug which alters brain chemistry. Kirsch et al reviewed 38 studies of antidepressants and found that patients whho received placebos fared almost as well as those getting real drugs.
Biological therapies: Drugs
Anti-psychotic drugs - These drugs block the action of the neurotransmitter dopamine in the brain by binding to, but not stimulating dopamine receptors. The drugs act by only temporarily occupying dopamine receptors and then rapidly dissociating to allow normal dopamine transmission.
Anti-depressant drugs- Depression is thought to be insufficient amounts of neurotransmitters such as serotonin being produced in the nerve endings, stimulating the…