S2. Biological Explanations For Schizophrenia Flashcards
1
Q
Schizophrenia Genetic Basis
A
- runs in families
- positive correlation between: genetic similarity between family members and risk of schizophrenia
2
Q
Schizophrenia Concordance Rates
A
- MZ Twins = 48% (due to sharing 100% of genes)(< 100% CR suggests environmental influence)
- DZ Twins = 17%
- Siblings = 9%
- Parents = 6%
3
Q
The Original Dopamine Hypothesis
A
hyperdopaminergia (abnormally high dopamine levels) in sub cortex is responsible for SZ
4
Q
The Revised Dopamine Hypothesis
A
hypodopaminergia (abnormally low dopamine levels) in sub cortex is responsible for SZ
5
Q
Modern Understanding of Dopamine Hypothesis
A
- both hypo and hyperdopaminergia in different areas of the brain contribute to SZ development
- HYPERdopaminergia in Broca’s Area responsible for auditory hallucinations due to over activity of neurotransmission in auditory areas of brain
- HYPOdopaminergia in prefrontal cortex (associated with logical thinking) impairs individuals ability to construct sentences (speech poverty) or function adequately (avolition)
6
Q
Neural Correlates
A
specific patterns of cortical activity, or neural structures, which coincide with specific psychological symptoms (and are therefore assumed to contribute to those symptoms)
7
Q
Neural Correlates Examples
A
- abnormally low activation levels in ventral striatum (associated with evaluating reward value, predictability, and risks)
- low activation/neurotransmission levels means that individuals cannot accurately assess the reward of having the motivation to carry out everyday tasks (avolition)
8
Q
+ Eval: Evidence supporting biological/genetic basis of schizophrenia
A
- risk of having SZ offspring increased by 1.3% if father was over 50, compared to u25
- suggests mutations in serotonin/dopamine production genes means SZ has strong heritability basis
9
Q
- Eval: Dopamine Hypothesis Evidence ‘Mixed’
A
- antipsychotics (dopamine antagonists/reducers) alleviated SZ symptoms
- however, role of dopamine overemphasised; roles of neurotransmitters glutamate and serotonin are key; antipsychotic Clozapine acted upon both substances (and more effective than other dopamine-focused antipsychotics)
