Biological Explanations For Schiz Inc Bio-chemistry, genetics

Question 1

Bio-chemistry

The dopamine hypothesis

Answer 1

Messages from neurons that transmit dopamine fire too easily/too often

Abnormally high numbers of DZ receptors result in more dopamine binding and more neurons firing

Dopamine neurons play a key role in attention so disturbances may lead to schizophrenic symptoms like attention and perception problems

Anphetamines - stimulates nerve cells containing dopamine causing synapse to be flooded - large doses cause characteristic hallucinations of schiz

Anti - psychotics - all block dopamine action in the brain - by reducing stimulation these eliminate symptoms

Parkinson’s disease - low levels of dopamine found in sufferers - people taking L-dopa were developing schiz symptoms

Question 2

Bio-chemistry

Dopamine hypothesis AO2

Answer 2

Post mortem studies - drugs used to treat schiz by blocking dopamine actually increase as neurons struggle to compensate for sudden deficiency

Neuroimaging research - allows researchers to investigate dopamine activity more closely but has failed to provide convincing evidence so far

Question 3

Bio-chemistry

Structural brain abnormalities

Answer 3

Torrey - enlarged brain ventricles - sufferers brain ventricles 15% larger - not ventricles that are the problem but loss of brain tissue that would have occupied them

Structural abnormalities around hippocampus inhibits emotional response

Question 4

Bio-chemistry

Structural brain abnormalities AO2

Answer 4

Cause and effect? Difference in neuroanatomical structure causing schiz or vice versa?

Conflicting research - ventricles diff sizes anyway - males naturally large, increase with age

Question 5

Genetics

Gottesmann and Shields

Tienari

Kety et al

Answer 5

G+S - 57 twins, 23 MZ, 34 DZ
If one MZ twin had schiz - 48% concordance rate
DZ - 17%
Sibling 9%

Tienari - 164 adoptees - biological mothers diagnosed with schiz - 11 (6.7%) recieved diagnosis comp to 2% of control group - nearly 7x higher than risk of general pop

Kety et al - 5483 Danish children - 32% of adoptees with schiz biological mothers developed disorders comp to 18% of control adoptees
Children born to non schiz parents and raised by schiz parents did not show any higher rates than norm pop

Question 6

Genetics AO2

Answer 6

Assumptions about twin environment - Joseph - MZ twins are widely more treated more similarly and identity confusion (“the twins”) - environment more similar

Rearing patterns - schiz may run in families due to rearing patterns - reasearch in EE showed negative emotional climate can lead to schiz outbursts