Lesson 4 - Biological explanations for skiz- genetics

Question 1

study by ripke

Answer 1

candidate genes may be responsible
- meta analysis done , 37k skiz compared to 11k ctrl
- 108 diff genetic variations were associated with increased risk of skiz
- these genes code for dopamine
- high dopamine = skiz

Question 2

weakness of ripke study

Answer 2

w- diathesis stress model , p more likely to be skiz if they have the gene for it & environment(stress) can trigger it
w- could be behavioural rather than genetic , learnt through operant conditioning

Question 3

strength of ripke study

Answer 3

+ lots of supporting research, genetics cannot be ignored as a cause for skiz
+ supported by dopamine hypothesis (high level of dopamine = skiz) this theory links high dopamine to genetics

Question 4

gottesman and shields twins study

Answer 4

• 224 sets of twins investigated
• one twin was already skiz
• 17% of DZ twins were concordant for skiz
  -48% MZ concordant
  result: skiz does have a genetic basis
• for DZ twins, genetics is less prominent as a cause(still greater risk than general public)

Question 5

strength of twin study

Answer 5

+ longitudinal, development of skiz monitored
+ reliable and valid bcs they diagnosed skiz using :
- in depth interviews
- doctor case notes
-DSM
more chance of inter rater reliability

Question 6

weaknesses of twin study

Answer 6

w- ignores behavioural approach. identical twins often copy each other(SLT) thus healthy twin copies skiz twin rather than genetics
w- relied on interviews w Ps, skiz p may find it difficult to communicate their issues and symptoms effectively, therefore negative effect on diagnosis of skiz