Biological Explanations for Schizophrenia

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Submitted By LucyBeer
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Outline and evaluate 2 biological explanations for schizophrenia.’ 24 Marks

One biological explanations for schizophrenia is genetic factors, which can be studied through twin studies. If the concordance rate is 100% in MZ twins it means that the characteristic is genetically determined because monozygotic twins share the same genes and environment. This was shown by Gottesman and Shields, who reviewed the results of 5 twin studies looking for concordance rates for schizophrenia. These studies looked at 210 MZ twins and 319 DZ twins. It was found that in MZ twins there was a concordance rate of 35-58% compared with dizygotic (DZ) twin rates that ranged from 9-26%. They also found a concordance rate in MZ twins of 75-91% when the sample was restricted to the most severe form of schizophrenia. This can show that there is a link with genetics and schizophrenia. However, the twin studies have all assumed that the shared environmental effects for MZ and DZ twins are equal which may be incorrect. In addition twins are not representative of the wider population. This is because it is a very small sample and there are very few MZ twins in the population and only 1% are Schizophrenic. This shows the sample may not be generalizable to the public.

In addition family studies support the idea that there is a genetic influence in schizophrenia. For example, if a parents is schizophrenic and a child becomes schizophrenic it would be likely that genetic factors responsible because children share 50% of their genes with each of their parents. Research has shown that the risk of schizophrenia risk rises with degree of genetic relatedness. For a child of someone who has schizophrenia, they have a 13% risk of getting schizophrenia. Whereas a spouse only has a 1% chance of getting schizophrenia which is the same as the general public. This shows that there could be a…...

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