Describe and Evaluate Biological Explanations for Schizophrenia [12 Marks]

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Describe and Evaluate Biological Explanations for
Schizophrenia. Refer to Evidence in your Answer. [12 Marks]
The biochemical explanation offers one explanation for the cause of schizophrenia
in terms of neurotransmitter release. It suggests that an excess of dopamine and a
message overload in the brain could cause schizophrenia. This is due to receptor
cells requiring dopamine to fire so with a large amount of dopamine present it is
activated too much and too many messages are sent. This is what could account for
the confused and erratic behaviour seen in schizophrenic patients.
Support for this theory is the effect of amphetamines: type of drug commonly
known as `speed'. These drugs work by significantly increasing dopamine levels.
When given to a non- schizophrenic the individual has been found to develop
schizophrenic-like symptoms, this therefore suggests that the increased
dopamine levels is likely to be linked to the disorder. In addition patients with
schizophrenia have been found to have symptoms worsen when they've taken
Further support is the use of antipsychotics, drugs that work by blocking
dopamine receptor cells and thus inhibiting firing and message overload. These
drugs are used to treat schizophrenics and so have been proven effective in
reducing symptoms. This supports the explanation as the drug is clearly effective
and so reinforcing the fact there may well be a causal relationship between
dopamine message overload and schizophrenia.
Antipsychotic support can be criticised since once individuals begin taking the
drug the blocking occurs relatively quickly so symptoms should improve straight
away. This however is not the case, it take a while for schizophrenic patients to
have improved symptoms so the disorder can't be purely dopamine and other
factors must be involved having an effect.
It can also be criticised due to the treatment aetiology fallacy (TAF) whereby you
cannot necessarily assume excess dopamine is the direct cause. TAF essentially
works backwards in the sense that from an effective treatment, a cause can be
established. For example a drug that prevents dopamine message overload helps
relieve schizophrenic symptoms so it is therefore assumed schizophrenia is
caused by message overload of excess dopamine. It is much better to firstly find
the cause of the disorder and then develop treatments after. In response to this

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criticism a second dopamine hypothesis was introduced which suggests rather
than excess dopamine causing the message overload, it may in fact be that
schizophrenics have too many receptor cells and thus more cells than normal fire,
causing the message overload. Owen's research supports this theory, since in
autopsy's taken on schizophrenic and non- schizophrenic individuals have shown
more dopamine receptor cells to be present in schizophrenics.…read more

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Richardson…read more


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