Describe and Evaluate the Biological Explanations of Schizophrenia (12marks)

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Describe and evaluate the biological explanations of schizophrenia. (12 marks) Schizophrenia is a psychotic disorder (or a group of disorders) marked by severely impaired thinking, emotions, and behaviors. The biological explanations for schizophrenia suggest that it is biological faults with the sufferer that induce schizophrenia. Included is that the condition is a genetic predisposition and is inherited from those who carry the gene, although the phenotype isn’t necessarily expressed. This is already a fault with the theory because this suggests that there must need to be an environmental trigger to set the condition off (therefore not wholly biological). The diathesis-stress model suggests that mental disorders occur when there is a genetic vulnerability, which is triggered by environmental conditions. However, Rabkin (1980) found that schizophrenics didn’t report any significant stressful event before the onset of the condition. However, these self-reports aren’t particularly reliable as the patient may not actually remember (possibly due to repression), want to say or be able to communicate an event which may have triggered it. Gottesman (1991) investigated twin studies of monozygotic and dizygotic twins. He summarized 40 concordance studies and found that when one of the twins was diagnosed with schizophrenia, monozygotic twins showed a 48% concordance rate over a 17% concordance rate in dizygotic twins. Due to the monozygotic twins sharing 100% of their DNA and dizygotic sharing only 50%, this shows that genetics are very likely to play a role in someone developing schizophrenia. However, due to concordance rates not being 100% in MZ twins, it also suggests that some environmental factors must play a role too. Loehlin and Nichols (1976) suggested that the high concordance rates in MZ twins is most likely to be due to the fact they will be treated very
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