💗 Schizophrenia Biological Explanation- Genetics Flashcards
(29 cards)
What is the biological explanation for schizophrenia?
Schizophrenia is a genetic illness that can be passed down from parents to children, and runs in families.
What do twin studies indicate about the genetic basis of schizophrenia?
They show concordance rates between monozygotic and dizygotic twins.
What was the concordance rate for schizophrenia among monozygotic twins found by Gottesman (1991)?
48%
What was the concordance rate for schizophrenia among dizygotic twins found by Gottesman (1991)?
17%
What notable finding did Rosenthal (1963) discover in studying quadruplets related to schizophrenia?
All four identical quadruplets developed schizophrenia, although age and onset differed
What concordance rate did Cardno et al. (1999) find for monozygotic twins?
40%
What concordance rate did Cardno et al. (1999) find for dizygotic twins?
5.3%
What are the concordance rates for schizophrenia among family members according to Gottesman (1991)?
- Identical twins: 48%
- Fraternal twins: 17%
- Children: 13%
- Siblings: 9%
- Parents: 6%
What did Gottesman and Bertelsen (1989) find regarding the risk of schizophrenia among children of parents with an identical twin who has the illness?
17% chance of being schizophrenic.
What do adoption studies suggest about the genetic basis of schizophrenia?
High concordance rates with biological families suggest a genetic basis.
What finding did Tienari (2000) report regarding children whose biological mothers had schizophrenia?
They were more likely to develop schizophrenia-related disorders.
What is the current thought regarding the cause of schizophrenia?
It is much more complex and results from multiple genes interacting (polygenic model).
What gene was identified by Sekar et al. (2016) as being linked to schizophrenia?
Complement component 4 (C4).
What role does the C4 gene play in the human brain?
It is involved in synapse pruning.
How does excessive pruning relate to schizophrenia symptoms?
It could lead to the symptoms seen in schizophrenia.
Why do schizophrenia symptoms appear after adolescence?
Due to the role of C4 in synapse pruning during adolescence.
What structural difference is observed in the brains of people with schizophrenia?
Thinner cerebral cortex with fewer synapses than healthy brains.
What do twin studies fail to consider in the context of schizophrenia?
Environmental factors that can influence the development of schizophrenia.
Environmental factors such as stress, trauma, or substance use may interact with genetic predispositions.
What is the concordance rate for non-identical twins compared to regular siblings in schizophrenia studies?
Non-identical twins have a much higher concordance rate than regular siblings despite having the same genetic similarity.
This indicates a potential environmental influence shared by twins.
What percentage of concordance do identical twins show in schizophrenia?
20-45% concordance.
This suggests that genetics alone cannot fully explain the occurrence of schizophrenia.
What role do environmental factors play in schizophrenia according to the text?
They may trigger schizophrenia and interact with genetic predispositions.
Factors like stress, trauma, or substance use can increase vulnerability.
What methodological issues do twin studies have in schizophrenia research?
They may overestimate the role of genetics due to assumptions about treatment similarity.
Identical twins often experience similar upbringings and social environments, which can affect outcomes.
What does Joseph argue about the treatment of identical twins in studies?
Identical twins are often treated more similarly than non-identical twins or siblings.
This can lead to similar mental health outcomes independent of genetics.
