Schizophrenia Booklet 3: Biological explanation of SZ Flashcards
What are the four sections of AO1 for the biological explanation?
- Overall Biological explanations for SZ
- Genetics
- Dopamine Hypothesis
- Neural Correlates
What would a biological psychologist argue is the cause of SZ?
Due to differences in our Biological Structures within tyhe body, such as genes, neurochemistry and brain structure, thus its aetiology has a physical basis
What does Genes refer to in SZ?
Genes and heredity. So for example we can identify genetic components through the use of twin and adoption studies
What does Dopamine refer to in SZ?
Neurochemistry. as it’s a neurotransmitter, therefore certain chemicals present in the brain/body that are linked to SZ
What does Neural refer to in relation to SZ?
Relates to the brain and how its structure may differ - e.g. certain structures or brain damages causing SZ
Genetic research highlighted the possibility that some people may be genetically at risk of developing SZ, it may be inherited. How do we investigate this?
Through twin studies, where MZ twins share 100% of genetics, and DZ twins share 50% of genetics.
What research do we have into genetics?
Gottesman reviewed 40 twin studies and found a 48% concordance rate for MZ twins, and a 17% concordance rate for DZ twins
This suggests that genetics do influence SZ as those who are more genetically similar are more likely to have SZ compared to those less genetically similar
What does the genetic explanation of SZ say about candidate genes?
-Researchers identified specific genes which make people more predisposed to SZ, these are known as candidate genes
-These genes associated with an increased risk of SZ and code for functioning of NT including dopamine
-No recognised one specific gene in particular for SZ, unlike OCD and aggression
What is the Dopamine hypothesis?
An explanation using neurochemistry, because dopamine is a NT.
-It suggests that there are actually two hypothesis for sz, these are: Hyperdopaminergia in the subcortex, and Hypodopaminergia in the cortex
Explain Hyperdopaminergia in the subcortex…
This means high levels of dopamine (hyper = surplus) in the subcortex
This excess of dopamine receptors in the Broca’s area is linked to positive symptoms such as auditory hallucinations
(In an exam, explain why this link has been made)
Explain Hypodopaminergia in the cortex…
This means low levels of dopamine in the prefrontal cortex
Low levels of dopamine in the prefrontal cortex, has been linked to negative symptoms such as avolition
(In an exam, explain why this link has been made)
What are Neural Correlates?
When a structure or function of the brain correlates with the development of SZ. Originally, conducted through post-mortem examinations on schizophrenics. Now examined through fMRI scans.
Research shows that enlarged ventricles are associated with SZ, enlarged ventricles also leads to damage to central brain areas and prefrontal cortex, linked to SZ
Explain how neural correlates could cause negative symptoms…
An area of the brain called the ventral striatum has been linked to avolition, as low levels of activity in this part of the brain has been correlated with both avolition and negative symptoms in general
Explain how neural correlates could cause positive symptoms…
Another area of the brain called the superior temporal gyrus has been linked to auditory hallucinations. Low levels of activity in this part of the brain correlate with auditory hallucinations
What are the evaluations of biological explanations of SZ?
🤓Evidence to support genetic exaplanation (Tienari)
🤓Evidence to support dopamine hypothesis (Curran)
🙄Not everyone with SZ responds to drugs (65% of people)
🙄Not clear which causes which (correlation study)
🙄Interactionist approach is better (recognises environmental factors)
