What are the key features of the biological approach?
Genetics, biochemistry and brain structure.
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How does genetics link with SZ?
100s of genes involved (polygenic), genes associated with the risk of SZ include those associated with coding for a number of neurotransmitters e.g. type 3 dopamine receptor gene.
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What is the evidence for SZ being linked to genes?
Gottesman - concordance rate of SZ was 17% for DZ twins and 48% for MZ. Shows strong evidence that genetics are an important cause of SZ.
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What is the 1/2 problems with using twin studies as evidence?
Concordance rates - MZ twins are genetically identical but CR aren't 100%, suggests other factors e.g. hostile family relationships or drug abuse.
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What is the 2/2 problem with using twin studies as evidence?
Sample size - MZ twins are rare and only 1% of them would be expected to have SZ so conclusions should be drawn cautiously.
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What is the evidence for SZ in adopted siblings?
Tienari - group 1 (155 adopted children who biological mum had SZ) group 2 (adopted children with no family history of SZ). 10% of group 1 developed SZ and 1% of group 2 developed SZ. Genetics are important but not complete explanation.
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What is dopamine?
A neurotransmitter found in the limbic system associated with attention and motivation.
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How is dopamine linked with SZ?
SZ symptoms due to increased dopamine activity at certain synaptic sites.
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What processes could explain why there is more dopamine activity in the synapse?
Release of excess dopamine by presynaptic neurons, more dopamine receptors on receiving neurons resulting in more dopamine binding to these receptors which triggers more neurons firing,
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What do dopamine neurons do and what may disturbances lead to?
Dopamine neurons help guide attention, so disturbances may lead to problems with perception, attention and thought, characteristic of SZ.
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What is the support for the dopamine hypothesis?
Antipsychotic drugs - Dopamine antagonists, which block the activity of dopamine in the brain, have reduced positive symptoms of SZ. This evidence supports the dopamine hypothesis because it suggests that dopamine imbalance is important in SZ.
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What is the problem with the dopamine hypothesis?
Antipsychotic drugs - not all patients benefit from drugs. Clozapine is a very effective treatment for SZ, it binds to dopamine and serotonin receptors. This suggests dopamine imbalance is not the only cause of SZ.
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What are neural correlates?
Measurements of the structure/function of the brain that correlate with symptoms of SZ.
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What are enlarged ventricles?
Fluid filled gaps between the brain areas.
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What have enlarged ventricles been associated with?
Damage to the prefrontal cortex.
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What's the support for neural correlates?
Weyandt found that enlarged ventricles were associated with negative symptoms of SZ. This is support because shows evidence for a relationship between SZ and enlarged ventricles.
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What is the problem of neural correlates?
Weyandt found that enlarged ventricles were associated with negative symptoms of SZ. This is a problem as it doesn't explain all symptoms (incomplete explanation).
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What are the problems with biological explanations?
Genes/excess dopamine activity/increased ventricles is only correlated with SZ. This means it's not possible to say that that these factors definitely cause SZ.
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What are the other explanations of SZ other than the biological explanation?
Psychological functions - family dysfunction and cognitive explanations.
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What is the interactionist approach?
SZ caused by interaction between biological, psychological, environmental factors. Diathesis stress model links genetic predisposition with life events. A genetic vulnerability leads to biochemical abnormality. Addition of drugs etc could trigger SZ.
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What are the practical applications of the biological explanation of SZ?
Having knowledge of biological explanations for SZ allows researchers to develop treatments to reduce symptoms e.g. antipsychotic medication. This shows that the research could have a positive impact in the real world.
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What are the issues and debates that link to the biological explanation of SZ?
Reductionism - oversimplifying a complex disorder however a reductionist explanation does offer avenues for treatments e.g. drugs.
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Other cards in this set
Card 2
Front
How does genetics link with SZ?
Back
100s of genes involved (polygenic), genes associated with the risk of SZ include those associated with coding for a number of neurotransmitters e.g. type 3 dopamine receptor gene.
Card 3
Front
What is the evidence for SZ being linked to genes?
Back
Card 4
Front
What is the 1/2 problems with using twin studies as evidence?
Back
Card 5
Front
What is the 2/2 problem with using twin studies as evidence?
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