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Biological explanations of schizophrenia Flashcards

1
Q

what are genes?

A

genes are sections of DNA that control the production of particular proteins

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2
Q

what do we call the different versions of a specific gene ?

A

alleles

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3
Q

what influence do genes have on complex behaviours?

A
  • there are multiple genes associated with complex behaviour
  • it is unlikely that one gene is responsible for for a behaviour
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4
Q

what does the genetic explanation say about schizophrenia ?

A

the more genetic alleles a person carries the more likely they are to develop schizophrenia. according to the genetic explanations of schizophrenia, if some family members have schizophrenia, then it is more likely that you will develop schizophrenia. this is because you may inherit a specific allele associated with schizophrenia

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5
Q

what does inherit mean?

A

the process by which genetic trait is passed on from parent to child.

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6
Q

what does allele’s mean?

A

the multiple variations of a DNA section that lead to different biological outcomes

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7
Q

what does concordance rate mean ?

A

the percentage of twins that both share the same trait, given that at least one twin has the trait

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8
Q

for a particular trait, there might be different concordance rates between monozygotic and dizygotic twins. what does this difference tell us about the influence that genetics has has on this trait?

A

a big concordance rate shows that genetics has a big influence on the trait compared to other factors

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9
Q

for Gottesman and shield’s study- as the concordance rates for monozygotic twins was not 100%, what can we say about schizophrenic development ?

A

schizophrenia is not just caused by genetics. schizophrenia development is also caused by the environment

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10
Q

what was the concordance rate for dizygotic twins in Gottesman and shield’s study?

A

24%

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11
Q

what was the concordance rate for monozygotic twins in Gottesman and shields study?

A

74%

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12
Q

what does the concordance rate for monozygotic twins (74%) show in Gottesman and shield’s study

A

the concordance for monozygotic twins shows that the environment also plays a role in the development of schizophrenia

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13
Q

what did Gottesman and Shield find in their study?

A

genetics contributes to the development of schizophrenia

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14
Q

what is one assumption that twin studies make?

A

the environment will have the same impact on phenotype for both monozygotic and dizygotic twins

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15
Q

what is a weakness of Gottesman and Shield’s study?

A

the study assumes that monozygotic twins and dizygotic twins have similar amount of shared environment. this is not true because identical twins are more likely to be treated the same than dizygotic twins. this mean that the high concordance rate for schizophrenia observed in monozygotic twins might be caused by shared environmental factors as well as shared genetic factors

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16
Q

what did Gottesman (1999) find about schizophrenia in families ?

A

studied families and concluded that if both your parents suffer from schizophrenia, then you have a 46% chance of developing it yourself, with 1 schizophrenic parent 13% chance and with a sibling a 13% chance and with a sibling with schizophrenia 9% chance. the more genetically similar relatives are the higher concordance is found

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17
Q

what do twin studies offer?

A

a unique opportunity for inventions of relative contributions of genetic and environmental influences

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18
Q

what did Gottesman find when he studied 40 pairs of twins

A

the concordance rate of MZ twins approximately 48% and 17% for DZ twins

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19
Q

what was the method for Tienari’s experiment?

A

the experimental group was adopted children whose biological children had schizophrenia. the control group was adopted children whose mothers didn’t not have schizophrenia

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20
Q

what are the limitations for adoption studies?

A
  • they assume that nay similarity between biological parent and adoptive child is solely down to genetics.
  • they ignore similarities in environments shared between adoptive children and their biological parents
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21
Q

if adopted children are often matched with adults to their similar to their biological parents, what does this mean for our interpretation of adoption studies?

A
  • similarities between adopted children and biological parents may also be a result of environmental influences.
  • adopted studies may over exaggerate the role of genetics.
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22
Q

evaluation of family studies

A

this evidence strongly suggests genetics is a factor. However, it could also explained in terms of the fact that genetically similar family members tend to spend more time together and so environment and recurring patterns rearing patterns could also affect the development of schizophrenia

23
Q

evaluation of twin studies

A

twin studies also suggest a genetic factor but they fail to look at the social class and social-psychology differences between twins. they also tend to use very small samples. environmental influences also fail to be considered. concordance rates should be 100% in MZ twins if there is a purely genetic cause

24
Q

what does the genetic explanations say about schizophrenia

A

schizophrenia is inheritable. there are particular gene alleles that increase the risk of developing schizophrenia

25
Q

what are the two main hypothesis for what brain abnormalities cause schizophrenia?

A

Neural correlates hypothesis

Dopamine hypothesis

26
Q

what does the neural correlates explanation say the disorder is caused by?

A

abnormal brain structures. for instance people with schizophrenia have large ventricles and a smaller frontal context

27
Q

what does an MRI scan do?

A

provides an image of the structure of the individual’s brain

28
Q

what are neural correlations ?

A

patterns of structure and activity in the brain that occur with a schizophrenic experience. as they occur simultaneously, this could lead us to believe that the patterns observed are implicated in causing schizophrenia.

29
Q

how did Torrey’s conduct his study to support neural correlates explanation

A
  • Torrey conducted an MRI scans with people with schizophrenia.
  • Torrey compared scans between people with schizophrenia and people with healthy brains.
30
Q

what are the findings of Torrey’s brain imaging study?

A
  • Torrey found that people with schizophrenia had 15% larger ventricles than those in the control group.
  • Torrey’s study supports the neural correlates explanation of schizophrenia
31
Q

people with schizophrenia are show to have enlargement in which part of the brain?

A

ventricles

32
Q

what rule do we have to keep in mind when looking at the results of the correlational study?

A

even if two variables correlate, it does not necessarily mean that one caused the other

33
Q

what are the limitations of the neural correlates hypothesis ?

A
  • the correlation between schizophrenia and brain abnormalities doesn’t mean that brain abnormalities cause schizophrenia. the medication that patients use may act as a confounding variable in studies of neural correlates
  • the neural correlates hypothesis ignores individual differences. there are individual differences in brain abnormalities displayed in patients with schizophrenia. not all schizophrenia patients display enlarged ventricles. the study support for the hypothesis doesn’t always replicate
34
Q

what can the enlarged ventricles be cause by?

A

the enlarged ventricles observed in patients with schizophrenia might be a side effect of the medication that the patients take

35
Q

what method is typically used to investigate the neural correlates hypothesis of schizophrenia?

A

MRI scans

36
Q

what is a strength of the neural correlates research?

A

the research into enlarged ventricles has high reliability. the reason for this is because research is carried out highly controlled environments which specialists high tech accurate leadings of the brain. the machine takes accurate readings of the brain regions such as frontal and pre-frontal cortex. this suggest that if this research was tested and retested the results would be achieved.

37
Q

what does dopamine do?

A

Dopamine is is a neuro transmitter that is involved in processing reward and in controlling attention

38
Q

what does dopamine deficiency results in?

A

Parkinson’s disease and people with low dopamine may be prone to addiction.

39
Q

in the mesolimbic system, dopamine has an excitatory effect. this means that there is high levels of dopamine ?

A

neurons generate more electricity activity than normal

40
Q

what does the dopamine hypothesis suggest schizophrenia is caused by?

A

abnormal brain function

41
Q

what are the dopamine levels in schizophrenia?

A
  • people with schizophrenia have higher levels of dopamine than healthy people.
  • the neurons of people with schizophrenia generate more electrical activity as those of healthy people
42
Q

where are neurons only overactive?

A

neurons are only over active in the mesolimbic system

43
Q

according to the dopamine hypothesis, in which area of the brain is there too much dopamine

A

mesolimbic pathway

44
Q

what does increased dopamine in the mesolimbic pathway lead to ?

A

according to dopamine hypothesis, increased levels of dopamine in the mesolimbic pathway cause neurons to become over active

45
Q

what do the revised dopamine hypothesis suggest about schizophrenia?

A
  • people with schizophrenia have levels of dopamine in the mesolimbic pathway.
  • Overactivity in the mesolimbic system causes the positive symptoms of schizophrenia.
  • people with schizophrenia have lower levels of dopamine in the frontal cortex than usual
  • underactivity causes negative symptoms
46
Q

according to dopamine hypothesis, what dysfunctional of the mesolimbic system commonly found in people with schizophrenia?

A

overactivity due the increase in dopamine levels

47
Q

according to the dopamine hypothesis, which symptoms of schizophrenia are caused by overactivity of the mesolimbic symptom?

A

hallucinations and delusions

48
Q

what does the revised dopamine hypothesis state about the frontal cortex ?

A

there is a lack of dopamine in this area, which manifests as the negative symptoms of schizophrenia

49
Q

what do revised dopamine hypothesis

A

states the positive symptoms of schizophrenia are caused by hyperactivity in the mesolimbic pathway, and that negative symptom of schizophrenia are caused by underactivity in the frontal cortex

50
Q

according to the dopamine hypothesis, if a person take an amphetamine, which increase dopamine, what should occur?

A

increased activity in the mesolimbic pathway.

51
Q

what combinations of schizophrenia symptom are likely to occur if someone takes an amphetamine, causing dopamine to increase in the mesolimbic pathway

A

hallucinations and delusions

52
Q

what are the two explanations for the role of dopamine of schizophrenia

A

hypERdopaminergia: excessive levels of dopamine in the sub cortex and broca’s area

hypOdyaminergia: low levels of dopamine in the prefrontal cortex

53
Q

limitations to the dopamine hypothesis

A

One of the biggest criticisms of the dopamine hypothesis came when Farde et al found no difference between schizophrenics’ levels of dopamine compared with ‘healthy’ individuals in 1990.

Noll (2009) also argues around one third of patients do not respond to drugs which block dopamine so other neurotransmitters may be involved.

A final weakness of the dopamine hypothesis is that it is biologically deterministic. The reason for this is because if the individual does have excessive amounts of dopamine then does it really mean that thy ey will develop schizophrenia? This suggests that the dopamine hypothesis does not account for freewill.

Schizophrenia (7 decks)

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