Biological Dysfunction as a Cause for Schizophrenia Essay

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Biological Dysfunction as a Cause for Schizophrenia

Schizophrenia is a mental disorder, which is characterised by a number of both positive and negative symptoms. Positive symptoms are behaviours which are present although should be absent. Examples of these are thought disorders resulting in difficulty in arranging thoughts logically, jumping from one topic of conversation to another and speaking random words. Other positive symptoms of schizophrenia include delusions whereby the effected person may feel that people are plotting against them and trying to kill them as well as hallucinations whereby the schizophrenic person hears voices in their head telling them to do things. Negative
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Kendler conducted a twin study and found that the concordance rate for monozygotic twins was 53% and the concordance rate for dizygotic twins was only 15%. This shows solid evidence for there being a hereditary component in the cause of schizophrenia. However as the concordance rate is not 100% and 50% for monozygotic and dizygotic twins respectively then this study also shows that environment does play some role. This theory was criticised as it was suggested that the higher concordance rate was due to monozygotic twins being exposed to a more similar environment than dizygotic twins. However the theory was proved wrong by a study, which showed that monozygotic twins that were reared apart still showed a 65% concordance rate.

Adoption studies strengthen the evidence to show how there is a hereditary component in the cause of schizophrenia by showing whether biological or adoptive relationships explain the familial transmission of the disease. Heston conducted a study whereby a
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