Biological explanations for schizophrenia - AO1 Flashcards
What do family studies show about schizophrenia and who did this study?
Show that genes and schizophrenia are interlinked: the risk of schizophrenia increases in line with genetic similarity to our relatives
Gottsman (1991)
- MZ = 47%
- DZ = 17%
- Parents = 6%
What is a candidate gene?
A gene that is believed to be related to a particular trait, such as a disease or physical attribute
What is polygenic?
There are a number of different genes involved
Schizophrenia is polygenic
What did Ripke et al. (2014) do?
Identified 108 separate genetic variations that were associated with slightly increased risk of schizophrenia
- Schizophrenia is aetiologically heterogeneous
How can a person have schizophrenia when there is no family history of it and what study finds this out?
Mutation in parental DNA
- Parental age is both associated with increased risk of sperm mutation and role of schizophrenia
- Brown et al. (2002): risk of SZ increased from 0.2% with fathers under 25 to 2% in fathers over 50
What is dopamine?
A neurotransmitter that generally has an excitatory effect and is linked to feelings of pleasure
What is the original dopamine hypothesis?
- High levels of dopamine are associated with SZ
- SZ is associated with hyperdopaminergia in subcortical areas of the brain
- This could explain positive symptoms such as hallucinations
What is the updated dopamine hypothesis and who proposed this?
Davis et al. (1991) proposed that cortical hypodopaminergia was also associated with SZ
- Low dopamine levels in the pre-frontal cortex could explain the negative symptoms experienced by those with SZ such as avolition
What is neural correlates?
Patterns of structure or activity in the brain that occur in conjunction with an experience
These “neural patterns” may be implicated in the origins of social experiences
