Schizophrenia (Genes) Flashcards
What is a gene?
The basic physical and functional unit of heredity.
What are genes made up of?
DNA.
How many genes do humans have?
Between 20,000 and 25,000.
How many copies of each gene does a person have?
Two copies, one inherited from each parent.
Is schizophrenia considered a genetic illness?
Yes.
What did Claridge and Davis (2003) conclude about genetic influences on schizophrenia?
Genetic influences are one of the few factual certainties about schizophrenia.
What did Rosenthal (1963) study?
Identical quadruplets, all diagnosed with schizophrenia.
What is the concordance rate?
A percentage that shows the degree of similarity between two people on a particular trait.
What are MZ twins?
Monozygotic twins (identical).
What are DZ twins?
Dizygotic twins (non-identical).
What was Gottesman’s (1991) finding regarding MZ and DZ twins’ concordance rates for schizophrenia?
48% for MZ twins and 17% for DZ twins.
What did Gottesman and Shields (1982) find about heritability and severity of schizophrenia?
Heritability varied depending on the severity of symptoms.
What is a weakness of twin studies?
Cannot distinguish cause and effect.
What increases the risk of schizophrenia according to Gottesman and Bertelsen (1989)?
Having a parent with an identical twin diagnosed with schizophrenia.
What is the purpose of adoption studies in schizophrenia research?
To overcome the issue of shared genes and environment.
What percentage of adoptees whose biological mothers had schizophrenia were also diagnosed according to Tienari et al (2000)?
6.7%.
What does polygenic mean in relation to schizophrenia?
Schizophrenia is likely determined by multiple genes.
What did O’Donovan et al (2014) identify regarding schizophrenia?
108 specific locations in the human genome linked with schizophrenia.
What is epigenetics?
The study of how the environment affects gene expression.
What is the diathesis-stress model?
The illness is caused by both genetic predisposition and environmental triggers.
What is a criticism of the genetic approach to schizophrenia?
It is reductionist and deterministic.
What is a limitation of the research on schizophrenia mentioned in the evaluation?
Small sample sizes and lack of generalizability.
True or False: Schizophrenia presents the same in all cultures.
False.
What did O’Donovan (2014) conclude about schizophrenia?
There is not one single gene that causes it, and it may not be a single disorder.
