Biological expl - Genetic Flashcards
What does the genetic explanation suggest?
Schizophrenia runs in families and can be inherited.
The closer the genetic relatedness the higher is the likely concordance rate for Schizophrenia
Schizophrenia is polygenic meaning it is likely that there are several genes that cause Schizophrenia and not one single candidate gene
What are the ways that the genetic explanation studies?
Family, twin and adoption studies
What are family studies?
They find individuals who have Schizophrenia and determine whether their biological relatives are similarly affected more often than non-biological relatives.
What is the study for family studies? What did it find? What does this suggest?
Gottesman - found that children with 2 schizophrenic parents have a concordance rate of 46%, 1 schizophrenic parent 13% and a schizophrenic sibling 9%
Suggests the more genetically similar to someone with schizophrenia, the higher the risk of developing Schizophrenia and therefore supports the genetic explanation
What are twin studies used for? Why?
To see if Schizophrenia is purely genetic - this is because MZ twins have 100% genes in common and DZ have 50%
What is the study for twin studies? What did it find? What does it suggest?
Gottesman and Shields (1982) conducted a meta-analysis of 5 studies of Schizophrenia in twins.
They found that MZ twins had a concordance rate of 46% where as DZ twins had a concordance rate of 14%
This suggests that genetics isn’t purely the cause of Schizophrenia, as the concordance rate for the MZ twins isn’t 100% - showing that other factors may cause Schizophrenia such as the environment
What are adoption studies? Why are they done?
Where a child with a/2 schizophrenic parent(s) are adopted into another family - this distinguishes the difference between genetic and environmental influences for individuals with schizophrenic relatives
What is the study for adoption studies? What did it find? What
Tiernari et al (2000) found that 164 adoptees whose biological mothers had schizophrenia - 7% developed schizophrenia where as only 2% of a control group of 197 adoptees (with non-schizophrenic parents)
