Outline and evaluate two biological explanations of schizophrenia

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  1. Outline and evaluate two biological explanations of schizophrenia

        There are many biological explanations of schizophrenia. In this essay I will concentrate on the genetic explanation and biochemical explanation of the disorder. There are many studies that look in to genetics and the link to schizophrenia. This is dues to an original finding that schizophrenia runs in families and therefore suggests that genes are responsible for the disorder. I study was preformed by Janicak et al 2001; they found that monozygotic twins have a 48% concordance rate. This is considerably less in dizygotic twins where the concordance rate falls to 17%. This would suggest there is a strong case for genetics being involved with schizophrenia. However if the disorder was caused entirely by genetics then we would expect a 100% concordance with monozygotic twins. A supporting study is one by Kety et al. 1988. This study found 14% of biological relatives of schizophrenic adoptee were schizophrenic, and only 2.7% of adoptive relatives. This backs up the claim for genetics although it still suggests there are other factors involved. The stress diathesis model could explain the differences in concordance rates. Gottesman also supports the genetic link, showing schizophrenia is more common in close biological relatives of a schizophrenic. However genetic explanations cannot account for the patients who have no family history of the disorder.

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        Biochemical factors are used to suggest that schizophrenia is caused by abnormal neurotransmitter activity. The main aspect of this explanation is the Dopamine hypothesis. Schizophrenia has been linked to with high levels of dopamine in the brain. Dopamine is a neurotransmitter associated with attention. Schizophrenics seem to have an increased number of D2 dopamine receptors on receiving neurons. This theory is support by the fact that Phenothiazines bind with D2 receptors and reduce positive symptoms. Another piece of supporting evidence is that Parkinson’s disease drug L-dopa, increase the level of dopamine and causes schizophrenic like symptoms in some people. However ...

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