Biological Explanations of Sz

Question 1

Outline the genetic theory as a biological explanation of Sz (3 marks)

Answer 1

Sz is hereditary and passed on from generation to the next via genes. A person can be born with a genetic predisposition. Sz is believed to be due to several maladaptive genes such as PCM1 interacting with other genes suggesting Sz is more likely to be polygenic so these genes increase vulnerability. These studies show 108 separate genetic variations associated with developing Sz. Gottesman studied 40 twins and found a concordance rate for MZ twins at 48% and DZ twins at 17% so the stronger the genetic link the higher the chance of developing Sz.

Question 2

Outline the dopamine hypothesis (3 marks)

Answer 2

Dopamine Hypothesis is where the neurotransmitters work differently in a brain with Sz. Dopamine may be released too much or there may be too many D2 receptors. Hyperdopaminergia in the subcortex is where there is high activity in dopamine in central areas such as Broca’s area which may be associated with auditory hallucinations. Hypodopaminergia in the cortex is low levels of dopamine in the prefrontal cortex and is associated with negative symptoms of Sz such as avolition.

Question 3

Outline neural correlates (3 marks)

Answer 3

Neural correlates is abnormalities in specific brain areas . Brain scanning techniques used to compare brains and identify areas that may be linked to Sz. One neural correlate of Sz is enlarged ventricles. Raz and Raz found that over half of participants, with Sz, studied had increased ventricle size compared to a control group who didn’t have Sz. This suggests enlarged ventricles are linked to damage to central brain areas and the pre-frontal cortex, argued to explain negative symptoms of Sz.