Biological explanations for schizophrenia

Question 1

What are the 3 parts of the genetic basis for SZ explanation

Answer 1

• Family studies
• Candidate genes
• Role of mutation

Question 2

Gottesman research

Answer 2

• Controlled genetic study
• Found risk of developing SZ was proportional to the amount of genetics they share with a schizophrenic

Question 3

Basic percentages of schizophrenia according to Gottesman’s research

Answer 3

• MZ twin = 48% risk
• Children with 2 affected parents = 46%
• DZ twin or children with 1 affected parent = 17% risk

Question 4

Candidate genes

Answer 4

• SZ appears to be polygenic
• Coding of neurotransmitters like dopamine
• Aetiologically heterogeneous

Question 5

Ripke research

Answer 5

• 37,000 patients with SZ genetic make up
• 108 separate genetic variations associated with increased risk of developing SZ

Question 6

Role of mutation

Answer 6

• Mutated parental DNA
• From poison, radiation or viral infection

Question 7

Browns research on the role of mutation

Answer 7

Comes from positive correlation between parental age and risk of sz

0.7% risk to fathers under 25
2% risk to fathers over 50

Question 8

Neural correlates

Answer 8

Patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience

Question 9

What are the 2 parts of the neural correlates explanation of SZ

Answer 9

• The original dopamine hypothesis
• Updated versions of the dopamine hypothesis

Question 10

Dopamine

Answer 10

A neurotransmitter that generally has an excitatory effect and is linked to the sensation of pleasure

Question 11

The original dopamine hypothesis

Answer 11

• SZ caused by high DA in subcortex
• Antipsychotics reduced the symptoms of SZ, but caused symptoms similar to the condition of Parkinson’s (Low DA)

Question 12

Hyperdopaminergia in the subcortex

Answer 12

• The original dopamine hypothesis
• High levels of DA in the subcortex

Question 13

Updated dopamine hypothesis

Answer 13

High DA in subcortex plus low DA in cortex explains negative symptoms

Question 14

Hypodopaminergia

Answer 14

• Low dopamine in the brain’s cortex
• Explain negative symptoms

Question 15

Biological explanations for schizophrenia (Genetic factors) evaluation points- Research support

Answer 15

STRENGTH

Family and adoption studies show heightened risk from biological parents (Tienari et al)
Twin studies show MZ 33% and DZ 7% concordance

Question 16

Biological explanations for schizophrenia (Genetic factors) evaluation points- Environmental factors

Answer 16

LIMITATION

• Biological factors (Birth complications and cannabis use)
• Psychological factors (Childhood trauma)

Question 17

Biological explanations for schizophrenia (Neural correlates) evaluation points- Evidence for dopamine

Answer 17

STRENGTH

• Amphetamines (increase DA) mimic symptoms
• Antipsychotic drugs (reduce DA) reduce intensity of symptoms
• Some candidate genes

Question 18

Biological explanations for schizophrenia (Neural correlates) evaluation points- Glutamate

Answer 18

LIMITATION

• Post mortem and scanning studies show high levels in people with SZ
• Some candidate genes associated with glutamate