biological explanations

Question 1

genetic explanations

Answer 1

family studies
candidate genes
mutation

Question 2

family studies

Answer 2

if one family member has schizophrenia then the chance of another member also being diagnosed increases as they become more genetically similar

Gottsman (1991)
- found identical twins have a 48% concordance rate
- fraternal twins 17%
- parents 6%
- compared to the general population is 1%

Question 3

candidate genes

Answer 3

schizophrenia appears to be polygenic
- a combination of different genes may cause it

genes responsible for coding dopamine neurotransmitters are most likely to be involved

Question 4

mutation

Answer 4

even with no history of schizophrenia it can be caused by a mutated gene of a parent

may be through :
- radiation
- viral infection
- poisoning

Question 5

evaluation of genetic explanation

Answer 5

environment
diagnostic criteria
addition studies

Question 6

environment (GENETIC EXPLANATION EVALUATION)

Answer 6

concordance rate for twins is not 100%

schizophrenia cannot be accounted for by genetics alone

Marked et al (2017)
- found that 67% of patients had experienced childhood trauma

Question 7

diagnostic criteria (GENETIC EXPLANATION EVALUATION)

Answer 7

Cardno et al (1999)
- used the ‘Maudsley Twin Register’
- uses strict diagnostic criteria
- found a concordance rate of 26% for identical twins and 0% for fraternal twins

cannot compare studies using different criteria

Question 8

adoption studies (GENETIC EXPLANATION EVALUATION)

Answer 8

Hiker et al (2018)
- found a concordance rate of 33% for identical twins and 7% for fraternal twins even though they were adopted

suggests a genetic basis

Question 9

neural correlates

Answer 9

dopamine hypothesis
ventral striatum
superior temporal gyrus and anterior cingulate gyrus

Question 10

dopamine hypothesis

Answer 10

hyperdopaminergia
- excess levels of dopamine receptors in the pathway from the sub cortex to the Broca’s area
-causes speech poverty / auditory hallucinations

hypodopaminergia
- low levels of dopamine in the prefrontal cortex
- causes problems with linking and decision making

Question 11

ventral striatum

Answer 11

used in the anticipation of reward

Juckel et al (2006)
- measured activity levels
- found lower levels of activity in schizophrenics compared to controls

Question 12

superior temporal gyrus and anterior cingulate gyrus

Answer 12

Allen et al (2007)
- reduced activity in these parts of the brain is a neural correlate for auditory hallucinations
- superior temporal gyrus and anterior cingulate gyrus

Question 13

evaluation of neural correlates

Answer 13

drug therapy
glutamate
correlations

Question 14

drug therapy (NEURAL CORRELATES EVALUATION)

Answer 14

antipsychotics reduce symptoms by reducing dopamine

amphetamines worsen symptoms as they increase dopamine

gives evidence for the dopamine hypothesis

Question 15

glutamate (NEURAL CORRELATES EVALUATION)

Answer 15

McCutcheon et al (2020)
- found schizophrenics have a deficiency in glutamate function
- could have a more important role in schizophrenic symptoms

Question 16

correlations (NEURAL CORRELATES EVALUATION)

Answer 16

correlations with brain areas does not imply causation

studies cannot explain why these areas have higher or lower activity