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BIOLOGICAL EXPLANATIONS - Coggle Diagram
BIOLOGICAL EXPLANATIONS
Sz runs in the family
- Eventhough the biological approach suggests this, there is generally weak evidence because families share aspects of their environment aswell as their genes
- This makes it difficult to distinguish whether genes or environmental factors have a greater influence on behaviour
Gottesman
- Conducted a meta-analysis of 40 European studies
- He then calculated the concordance rate of the relatives of a Sz sufferer
- The percentage risk of developing Sz in the general population is 1% but Gottesman found this increased dramatically to 46% concordance for offspring of 2 Sz parents + increase to 48% for monozygotic twins (Mz)
- Therefore, the closer the degree of relatedness, the higher the risk of Sz
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Neural correlates
- Refers to the structure/function of the brain that correlates with an experience
- Neural correlates for negative symptoms include abnormality e.g. abnormality in the ventral striatum is linked to Sz
- Juckel found out that lower levels of activity in this area of the brain compared to controls suggesting it is linked to Sz
The dopamine hypothesis
- States that dopamine works differently in the brain of Sz's
- Excess dopamine in certain areas of the brain results in hallucinations + delusions (+ symptoms)
- Sz's have abnormally high numbers of D2 receptors on receiving neurons which results in more dopamine binding + more neurons firing
- States that a deficit of dopamine in certain areas of the brain (prefrontal cortex) are linked to negative symptoms e.g. speech poverty
- PET scans have shown lower levels of dopamine in the prefrontal cortex of Sz's + animal studies have shown that depleting dopamine in rats prefrontal cortex = cognitive impairment such as memory loss
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