Genetics - (Biological explanation)

Question 1

What does the genetic explanation believe?

Answer 1

• schizophrenia tends to run in families

- schizophrenia is hereditary

Question 3

What are the 3 types of methods used to study genetic role in schizophrenia?

Answer 3

• family studies
• twin studies
• adoption studies

Question 4

What is the extent of genetic relatedness in families?

Answer 4

• compare parents and children

- share 50% of DNA

Question 5

Describe the key research into family studies

Answer 5

Gottesman (1991):

• p’s w/ 2 schizophrenia parents - 46% chance
• p’s with 1 schizophrenia parent - 13% chance
• higher genetic similarity = higher concordance rate

Question 6

What is the extent of genetic relatedness in twin studies?

Answer 6

• compare concordance of MZ twins to DZ
• MZ - 100% DNA
• DZ - 50% DNA

Question 7

What are the key findings for twin studies?

Answer 7

Gottesman and Shields (1966):

• used psychiatric home records over 16 years
• studied 57 pairs
• half were MZ twins
• concordance rate: MZ = 54%, DZ = 18%
• higher genetic link = higher concordance rate

Question 8

What is the extent of genetic relatedness for adoption studies?

Answer 8

• compare child and biological parent

- look’s at their different environments

Question 9

What are the key findings for adoption studies?

Answer 9

Tienari (2000):

• looked at 164 adoptees
• their bio mums were schizophrenic
• 6.7% adoptees diagnosed as schizophrenic vs 2% of control adoptees
• higher rate of schizophrenia in the biologically similar relatives

Question 10

What other studies have been used to study genetics role in schizophrenia?

Answer 10

• genetic mapping studies
• found that there are multiple genes affect development of schizophrenia
• polygenic

Question 11

What research was done into gene mapping studies?

Answer 11

Ripke (2014):

• DNA of 36,989 schizophrenics vs 113,000 non schizophrenics
• identified 128 genetic variations at 108 locations
• contribute to developing schizophrenia
• higher genetic expression = schizophrenia

Question 12

Why are families looked at to study schizophrenia?

Answer 12

• to assess the concordance rate of developing schizophrenia between p’s of different genetic relatedness

Question 13

what are the strengths of the genetic explanation?

Answer 13

• supporting research

- practical applications

Question 14

what is the supporting research for the genetic explanation?

Answer 14

Heston (1966):

• researched 50 adoptees w/o schz parents and 47 w/ schz parents
• all p’s separated from parents at birth
• 10.6% of p’s w/ schz parents developed schz
• 0 p’s w/o schz parents developed schz
• suggests a genetic link

Question 15

what are the practical applications of the genetic explanation?

Answer 15

• if child has schz parents they’re at higher risk
• can intervene early
• try to manage childs environment to prevent triggers
• reduce p’s w/ schz
• therefore NHS spends less money on schz

Question 16

what are the weaknesses of the genetic explanation?

Answer 16

• nature/ nurture
• ignores role of the family
• methodology

Question 17

how is nature/ nurture a weakness of the genetic explanation?

Answer 17

• ignores environment
• just cause we have a gene doesn’t mean it’ll be expressed
• environment affects if gene is switched on or not
• more likely an interaction of nature and nurture

Question 18

how does the genetic explanation ignore the role of the family?

Answer 18

• cold / rejecting mum can cause a tense environment
• can be catalyst for schz symptoms
• genetics can’t be the sole reason for such a complex disorder
• e.g consider family dysfunction explanation

Question 19

how is methodology a weakness of genetics?

Answer 19

• research with twins never finds 100% concordance rate
• MZ treated more similar than DZ
• MZ more likely to share environment than DZ
• MZ more likely experience ‘identity confusion’
• can’t ignore environment factors