Biological Explanations of SZ

Question 1

What are the 4 AO1 points?

Answer 1

Family Studies
Twin Studies
Adoption Studies
The Dopamine Hypothesis

Question 2

What are the the 5 AO2 points?

Answer 2

Family Studies
Twin Studies
Methodological Flaws
Post Mortem Studies
An Evolutionary Perspective

Question 3

What do family studies investigate?

Answer 3

Whether SZ relatives are more likely to be affective by non relative, as higher proportion of shared genes

Question 4

What has been established from family studies?

Answer 4

SZ more common among biological relatives of SZc

Question 5

Family Studies: the closer the degree of genetic relation…

Answer 5

The higher the risk of SZ dvlpt

Question 6

What have family studies concordance rates shown?

Answer 6

46% with 2 SZ parents
13% with 1 SZ parent
9% SZ sibling

Question 7

What does concordance rates in family studies demonstrate?

Answer 7

Lend support to theory of genetic basis

Question 8

Twin Studies..If MZ twins (share 100% of their genes)

Answer 8

Are concordant in a trait such as SZ compared to DZ twins, there must be a genetic basis

Question 9

Twin studies. If MZ twins are concordant in SZ then?

Answer 9

Nurture can be discounted to some extent, as twins would share same environment

Question 10

What did Joseph find in relation to twin studies?

Answer 10

Identical twins - 40%
Non I twins - 7.4%
Strong argument for genetic factors

Question 11

In adoption studies, why are genetically related individuals reared apart used?

Answer 11

To disentangle environmental influences from genetics (compared to control group of adoptees with non SZ parents)

Question 12

What did Tineari find?

Answer 12

11/164 children whose mothers have SZ

4/197 of control group with no SZ genes

Question 13

What do Tinearis findings show?

Answer 13

Supports the role of genes in influencing onset of SZ

Question 14

What is a flaw of Twin Studies?

Answer 14

Assumed that high concordance rates are a product of greater genetic similarity rather than environmental similarity - CRITICAL

Question 15

What might higher concordance rates be due to rather than genetic similarity?

Answer 15

Identical twins being more inclined to similar treatment/viewed as one person so sharing the same environment (Joseph)

Question 16

How is the idea that it might be environment rather than genes reinforced?

Answer 16

40% concordance not 100%? Environment must play a large mitigating role…

Question 17

A third and final reason why higher concordance rates might be due to environment rather than simply genetic vulnerability?

Answer 17

• Diathesis Stress Model, g/e interaction

- Environmental triggers and stressors might activate genetic vulnerability for SZ

Question 18

What is a problem with adoption studies?

Answer 18

Assumption that SZ children not selectively placed

Question 19

What did Joseph claim regarding placement of SZ children?

Answer 19

• Parents informed of genetic vulnerability
• Might wonder what sort of parents would continue with adoption
• Skewing results

Question 20

What is a methodological issue regarding SZ adoption studies?

Answer 20

• SZ spectrum broadened to accomodate sz spectrum disorders

Question 21

What would might have happened if SZ definition wasnt broadened for adoption studies?

Answer 21

Same statistical would not have been found

Question 22

What is the Dopamine Hypothesis?

Answer 22

• Neurons transmitting dopamine fires too easily/often

- Strangely high numbers of D receptors on receiving neutrons, so more dopamine binding/neuron firing

Question 23

What do D neurons play a role in?

Answer 23

Guiding attention, so disturbances may well lead to problems relating to attention such as SZ

Question 24

How do AP’s strengthen the case of Dopamine playing a role in SZ?

Answer 24

Block dopamine activity and in turn eliminate symptoms such as hallucinations

Question 25

What is a major problem with the Dopamine hypothesis?

Answer 25

-Dopamine blocking drugs can actually increase D levels

Question 26

Why can dopamine blocking drugs increase D levels?

Answer 26

Neutrons struggle to compensate for D deficiency

Question 27

What do post mortem studies show?

Answer 27

• Those with increased D levels

- Many of which had received APs shortly before death

Question 28

Why might Sz be an ancestral/evolutinary disorder?

Answer 28

Originated in ancestral humans

Australian Aborigines became isolated from rest of human kind yet SZ still observed

Question 29

Why might SZ be adaptive?

Answer 29

• Help split tribal communities to prevent uproar

- Charasmatic ppl facilitate the splitting of groups, bizarre beliefs etc help influence unhappy members in leaving