Biological explanation for schizophrenia: Genetic

Question 1

What was Gottesmans study on the genetic explanation of schizophrenia ?

Answer 1

• large scale family studies
• fraternal twins had 17% chance of developing schizophrenia
• identical twins have 48% risk of developing schizophrenia
• this shows that the more genes shared - the higher the likelihood of developing schizophrenia
• Due to the percentage being 48% and not 100% it shows that there is a genetic component but it isn’t fully genetic
• Correlation but not causation

Question 2

Is schizophrenia polygenic ?

Answer 2

• yes
• there is more than one ‘schizophrenic gene’
• E.g. NRG1, NRG3
• different combinations of genes can lead to schizophrenia
• also known as aetiologically heterogeneous

Question 3

What was Ripke’s study ?

Answer 3

• meta analysis
• found 108 separate genetic variations associated with an increased risk of schizophrenia

Question 4

What are the limitations of the genetic explanation ?

Answer 4

Polygenic
- difficult to identify which genes are implicated/involved
- this means it is difficult to predict someones risk of developing SZ

Not 100% genetic
- concordance rates in family studies fail to show a complete genetic explanation
- suggests that other factors are involved
- biological reductionism is limiting - SZ is more than just basic units

Question 5

What are the strengths of the genetic explanation ?

Answer 5

Application to genetic counselling
- parents have an informed understanding of the risk of passing SZ to potential offspring
- allows for an informed decision to be made by parents

Biologically deterministic
- suggests genes cause SZ
- it’s not due to free will
- helps patients know that it’s not their own fault and they aren’t choosing to act this way - out of their control

Biologically reductionist
- more traditional
- objective research helps to identify basic genetic units
- gives psychology greater scientific credibility