Biological and Cognitive Explanations For Schziophrenia


- Dopamine Hypothesis and Evaluation

- Genetic Explanation and Evaluation


- Processing Explanation and Evaluation

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Preview of Biological and Cognitive Explanations For Schziophrenia

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Biological Explanation for Schizophrenia
Genetic Factors:
Schizophrenia appears to run in families and therefore has a genetic link. Generally it is
thought that schizophrenia is caused by a number of genes rather than just one gene.
For example, Hong et al found that the THP gene was more common in Chinese
Schizophrenics, and the International Schizophrenia Consortium found that schizophrenics
are more likely to have structural changed to their genes. Abnormalities were found in
chromosomes 22, 1 and 15 where they all had missing DNA compared to normal genes.
Both family and twin studies have been used to study the genetic factors to
Strengths Weaknesses
Gottesmen show that there is a genetic Although Gottesmen show that there is a
link as the chances of the general genetic link, it also shows there are
population getting schizophrenia is 1%. other factors which contribute to
However, it rises to 48% of you have an schizophrenia. If the environment had no
identical twin with the condition. influence, any pair of identical twins
Heston shows a genetic link too. 10% of would have a 100% chance of
adopted children whose biological developing schizophrenia.
mother had schizophrenia developed it, The study is reductionist as there are
where as none of the other adopted other factors which play a huge part in
children who mothers didn't have people developing schizophrenia.
schizophrenia developed it.
Biochemical Factors:
The dopamine hypothesis looks at the role of the neurotransmitter dopamine as a cause
of schizophrenia.
The drugs that are used to treat schizophrenia cause symptoms similar to Parkinson's
disease, which are low levels of dopamine.
It is therefore assumed that drugs administered to cure schizophrenia because dopamine
levels to drop, as they block the dopamine receptors and as these drugs treat
schizophrenia. It must therefore be high levels of dopamine or too many dopamine
receptors which cause schizophrenia.
Strengths Weaknesses
Lindstroem found using PET scans that It is hard to know if excess dopamine
show more dopamine is made in causes schizophrenia or schizophrenia
schizophrenics. causes excess dopamine.
Donnelly found that more homovanillic Depatie and Lal found that a drug that
acid (a waste product of dopamine) is increases dopamine levels did not cause
produced in schizophrenic patients, schizophrenic symptoms.
suggesting they produce more

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Cognitive Explanation for Schizophrenia
Processing Factors:
The approach sees the cause of schizophrenia coming from issues with processing
information. It is thought that schizophrenics have distorted beliefs and that these beliefs
influence their behaviour.
They may process what was meant to be a neutral message, as something directive
negatively. They also can't reflect on their own thoughts and behaviour, so they have
problems recognising that they are in control of themselves. They often feel that their
behaviour is controlled by an outside agency.…read more


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