Biological explanation: genetics Flashcards
what does the genetics explanation put an emphasis on ?
- emphasis on the role of inherited factors and dysfunction of brain activity in the development of schizophrenia
what do biological explanation accept ?
- accepts that there is a relationship between the biological predispostion for schizophrenia and the role that psychological factors may play in the onset of schizophrenia
- diathesis stress model
what does the genetic explanation suggest ?
- suggests that schizophrenia tends to run in families
- and amongst individuals that are related
what is the risk of developing schizophrenia for individuals who have family members who have it ?
- it is greater than it is for those who don’t
what has not been identified ? and why ?
- a single gene responsible for schizophrenia has not been identified
- seems that different combinations of genes make an individual more vulnerable
what is meant by a candidate gene ?
- gene that is potentially linked with schizophrenia
what kind of genes are associated with the risk of inheritance ?
- individual genes
what is it meant by schizophrenia is polygenic ?
- a number of factors need to work in combination to develop schizophrenia
what is meant by schizophrenia being aetiologically heterozygous ?
- different combinations of factors can lead to schizophrenia
how can you determine if there is a genetic influence on a disorder ?
- peform twin studies
who conducted twin studies on schizophrenia ?
Gottesmann 1991
what have family studies shown ?
- they have shown that schizophrenia is more common among biological relatives
the greater the risk of developing schizophrenia…
the closer the degree of genetic relatedness
what is the concordance rate in siblings when 1 sibling has developed schizophrenia ?
9%
what is the concordance rates for MZ twins ?
48%
what are the concordance rates for DZ twins ?
17%
what is the concordance rate in the general population ?
1%
who did the same study as Gottesmann to check the reliability ?
Joseph 2004
Joseph
- MZ twins concordance rate ?
40%
Joseph
DZ concordance rate ?
7%
what study was done after the twin study and why ?
- adoption study
- to eliminate the growing up in the same environment factor
who carried out the adoption studies ?
Tienari (2000)
who were Tienari’s ps in his adoption studies ?
- studied 164 adoptees whose biological mother had been diagnosed with schizophrenia
how many of the adoptees developed schizophrenia ?
- 11/164 (6.7%)
how many adoptees developed schizophrenia in the control group ?
4/197 (2%)
what does Tienari’s study support ?
- it supports a genetic liability for schizophrenia
