Biological explanation for Schizophrenia

Question 1

What chance do you have of developing SZ if your sibling has it? (Gottesman)

Answer 1

9%

Question 2

What chance do you have of developing SZ if your MZ twins? (Gottesman)

Answer 2

48%

Question 3

What chance do you have of developing SZ if your DZ twins? (Gottesman)

Answer 3

17%

Question 4

What is polygenic, and what correlation does that have with SZ?

Answer 4

Polygenic = when there are a number of candidate genes which make up one disorder.
-> SZ is polygenic.

Question 5

What is the most common neurotransmitter which codes for SZ?

Answer 5

Dopamine.

Question 6

How many people did Ripke have in his sample who were diagnosed with SZ?

Answer 6

37,000

Question 7

How many controls (without SZ) did Ripke have in his sample?

Answer 7

113,000

Question 8

How many separate genetic variations were associated with an increased risk of SZ?

Answer 8

108 candidate genes.

Question 9

What did the findings from Ripke’s study tell us about SZ?

Answer 9

It’s aetiologically heterogeneous.

Question 10

What did Ripke’s study consist of?

Answer 10

He compared the genetic makeup of people with SZ to controls to find candidate genes with risk the onset of SZ.

Question 11

What causes mutation in parents DNA?

Answer 11

Radiation, poison or viral infection.

Question 12

What’s the risk of fathers with mutated sperm having kids who develop SZ according to Brown et al (2002)?

Answer 12

-0.7% in fathers under 25.
-2% in fathers over 50.

Question 13

What is the best known neural correlate for SZ?

Answer 13

The neurotransmitter dopamine.

Question 14

What was the original dopamine hypothesis based on?

Answer 14

Based on the discovery that drugs used to treat SZ caused symptoms similar to those in people with parkinson’s disease.
(Parkinsons = a condition associated with low DA levels).

Question 15

What might SZ be a result of according to the original dopamine hypothesis?

Answer 15

High levels of DA (hyperdopaminergia) in the subcortical areas of the brain.

Question 16

What part of the brain may explain specific symptoms like speech poverty/ auditory hallucinations?

Answer 16

Excess levels of DA receptors in pathway from the subcortex to Broca’s area.

Question 17

What did David et al (1991) propose in the updated dopamine hypothesis?

Answer 17

The addition of cortical hypodopaminergia (abnormally low DA in the brains cortex).

Question 18

What does the updated dopamine hypothesis tell us about SZ?

Answer 18

Cortical hypodopaminergia leads to subcortical hyperdopaminergia; so meaning both high and low levels of DA in different brain regions are part of the updates version (increase risk of SZ).

Question 19

What does the neural explanation say about SZ according to Howes (2017)?

Answer 19

Both genetic variations and early experiences of stress, both psychological and physical, make some people more sensitive to cortical hypodopaminergia and hence subcortical hyperdopaminergia.