1. Week 2 Lesson 1 – Bio explanations (AO1)
Lesson 2 – Psycho explanations (AO1)
Lesson 3 – Evaluating bio explanations

2. Explanations of schizophrenia
Psychological
Family dysfunction (double bind and expressed emotions)
Cognitive explanation (dysfunction thought processing)
Biological
Genetics
Dopamine hypothesis
Neural correlates

3. Today…. Biological explanations Building on prep work so you can…
Outline the bio explanations effectively
Apply bio explanations to scenarios

4. Group the following key terms/studies in relation to what biological explanation they relate to:
Scanning techniques e.g. fMRI
Candidate gene
Prefrontal cortex
Polygenic
Kety and Ingraham (1992)
Glutamate
Monozygotic and dizygotic
Gottesman (1991)
Neurotransmitter
Superior temporal gyrus and Anterior cingulate gyrus
Subcortex
Enlarged ventricles
Prefrontal cortex
Concordance

5. Answers Genetics: Gottesman (1991) Candidate gene Polygenic
Kety and Ingraham (1992)
Monozygotic and dizygotic
Concordance
Dopamine hypothesis:
Neurotransmitter
Glutamate
Prefrontal cortex
Subcortex
Neural correlates:
Scanning techniques e.g. fMRI
Superior temporal gyrus and Anterior cingulate gyrus
Enlarged ventricles
Prefrontal cortex

6. Twin studies – answers in notebooks
1. There are two versions of twins – draw stick people to show the difference between these types.
Twin type:___ AKA:____
Genes shared = ______
Twin type:___ AKA:____
Genes shared = ______
2. Dave is one half of a Mz twin pairing. He suffers from Schizophrenia. Assuming Sz is completely genetic. What are the chances of his identical twin Arnold developing the disorder. Explain your answer?
3. Arnold does not suffer from Sz. Are Dave and Arnold concordant? What is meant by a concordance rate?
4. It is assumed that MZ and DZ twins share ‘equally similar environments’; what does this mean?

7. Answers:
MZ (identical)- 100% genes shared; DZ (non-identical) -50% genes shared
If you assume that schizophrenia is completely genetic, the chances of Arnold developing the disorder is 100%. This is because Dave and Arnold are genetically identical so the gene(s) determining Dave’s disorder will also be present in Arnold.
No they are not concordant as they BOTH do not have SZ.
Concordance rate refers to the percentage of twins that share a particular trait. If a behaviour is completely genetic, the percentage in MZ twins should be 100%, and in DZ twins should be somewhere around 50% (if concordance rate was 27%, 27 out of 100 twins would BOTH have the disorder)
MZ twins usually grow up in the same household, with the same parents, in the same area and culture, share friends etc. They have very similar environments. This is the same for DZ twins. Therefore, MZ and DZ twins share ‘equally similar environments’

8. Genetics
Concordance rates for developing schizophrenia (Gottesman, 1991): DZ – 17% MZ – 48% Task: Write a short paragraph explaining what this data suggests about the role of genes in schizophrenia

9. E.G.
Suggests schizophrenia is at least in part genetically influenced because MZ twins share 100% of their genes and DZ share only 50% which may explain the higher concordance rates for schizophrenia in MZ twins.
Twin studies assume that MZ and DZ twins share equally the similar environments e.g. both MZ & DZ share the same parents, home, schools etc.
Therefore only the difference in genes shared can explain the difference in MZ and DZ concordance rates thus suggesting a genetic role in the development of schizophrenia.

10. Pre-frontal cortex (front of frontal lobe.
Thought processing, memory, decision making, learning
Speech production
Dopamine hypothesis
Which of the pictures above is the correct hemisphere for Broca’s area?
Very briefly sketch the correct hemisphere and label where Broca’s area and the pre-frontal cortex is.
What is the function of Broca’s area?
What are some of the primary functions of the pre-frontal cortex

11. Dopamine hypothesis
What do different theories say about how levels of dopamine lead to the symptoms we see?
Fill in the blanks with:
high/low levels of dopamine
the brain area it affects
the resulting symptom
1)______ -> 2)_______e.g. -> 3)_________
1) ______ -> 2)_______e.g. -> 3) _________

12. answers High levels -> 2) subcortex e.g. Brocas area
-> 3) poverty of speech, auditory hallucinations
Low levels
-> 2) cortex e.g. prefrontal cortex
-> 3) negative symptoms e.g. decision making

13. Neural correlates- based on knowledge from prep work
Why do researchers use brain scanning techniques to investigate schizophrenia?
Who do they compare?
What sort of tasks might they ask someone to do in the scanner and why?
Whose early research found that schizophrenics have larger _________?
________ symptoms are associated with larger ________?
Research by Allen et al. found lower activation levels in which 2 of these brain areas: superior temporal gyrus, anterior temporal gyrus, basal ganglia, anterior cingulate gyrus
This was associated with which positive symptom?

14. to compare the functioning of the brains and to identify brain areas that may be linked to the disorder
Sufferers of schizophrenia vs. non-sufferers
tasks associated with types of functioning known to be abnormal in sufferers, for example social cognition, thought processing and working memory tasks.
Johnstone et al., ventricles
Negative symptoms, ventricles
Superior temporal gyrus, anterior cingulate gyrus
Auditory hallucinations

15. Neural correlates- based on knowledge from prep work
Why do researchers use brain scanning techniques to investigate schizophrenia? to compare the functioning of the brains and to identify brain areas that may be linked to the disorder Who do they compare? Sufferers of schizophrenia vs. non-sufferers What sort of tasks might they ask someone to do in the scanner and why? tasks associated with types of functioning known to be abnormal in sufferers, for example social cognition, thought processing and working memory tasks.

16. Whose early research found that schizophrenics have larger _________
Whose early research found that schizophrenics have larger _________? Johnstone et al., ventricles ________ symptoms are associated with larger ________? Negative symptoms, ventricles Research by Allen et al. found lower activation levels in which 2 of these brain areas: superior temporal gyrus, anterior temporal gyrus, basal ganglia, anterior cingulate gyrus Superior temporal gyrus, anterior cingulate gyrus This was associated with which positive symptom? Auditory hallucinations

17. Neural correlates – what came first ?
Did the brain abnormality cause the SZ or did the SZ cause the brain abnormality?
Discussion in pairs:
What do you think?
Is there anyway psychologists can investigate this/find out?

18. Peer or self mark - your choice
Exam practice
Choose one of the following to answer now under timed conditions:
Outline the genetic explanation for schizophrenia (4)
Outline the dopamine hypothesis as an explanation of schizophrenia (4)
Outline the neural correlates explanation of schizophrenia (4)
Outline one or more biological explanations of schizophrenia (4)
Peer or self mark - your choice

19. Outline the genetic explanation for schizophrenia (4)
2 marks for any of the following:
Genetic explanation sees schizophrenia as transmitted through genes passed on to individuals from their families. Family studies such as Gottesman suggests the closer the degree of genetic similarity the higher the risk of developing the disorder. Thus schizophrenia may be due to a genetic predisposition
Twin studies of the differences between concordance rates of Monozygotic and Dizygotic twins indicates a genetic cause, concordance rate for MZ twins is 48% versus 17% for Dizygotic. As twins both MZ and DZ are likely to share similar environments the fact MZ share 100% of their Genes as compared to DZ sharing 50% suggest it must be a genetic cause.
It is not believed there is a single ‘schizophrenic’ gene, there are several genes involved that increase an individuals overall vulnerability – this is a polygenic approach. The are a number of different candidate genes that have been identified, Ripke found 108 separate genetic variations.
Genes associated with increased risk included those in the brain and in tissues with an important role in immunity as well as coding for neurotransmitters such as dopamine.

20. Outline the dopamine hypothesis as an explanation of schizophrenia (4)
2 marks for any of the following:
Dopamine is a neurotransmitter which is thought to work differently in the brains of those with SZ. Dopamine acts to increase the rate of firing in the synapse of neurons, which enhances communication.
Hyperdopaminergic explanations focus on high levels of dopamine in the subcortex such as brocas area which may be associated with poverty of speech/ auditory hallucinations
Hypodopaminergic explanations suggest low levels in the cortex. Such as pre-frontal cortex which expresses negative symptoms e.g. thinking, decision making
It therefore seems to be the case that both high levels of dopamine and low levels can be associated with the onset of SZ
It is likely that differences in dopamine levels are a result of inherited genetic differences in the coding of dopamine.

21. Outline the neural correlates explanation of schizophrenia (4)
1 mark for each of the following:
The Neural correlates explanation focuses on the functioning of specific localised brain areas, suggesting that the brain functioning of those with Sz is different to those without.
Much of the research uses scanning techniques to compare the brain functioning , in which tasks associated with types of functioning know to be abnormal in sufferers are given to participants.
Further 2 marks for one of the following:
One link between brain functioning and SZ is enlarged ventricles (fluid filled gaps) particularly in the pre-frontal cortex which has been associated with negative symptoms such as avolition and speech poverty
Positive symptoms such as auditory hallucinations have been correlated with lower neural activity in the superior temporal gyrus and anterior cingulate and it is thought this is due to this area being associated with ones ability to discriminate between internal and external stimuli