A01 biological explanations of schizophrenia Flashcards
Which explanation for schizophrenia recieved most support
Biological
What are the 2 main sections
Genetic factors
The dopamine hypothesis
What are the 3 sections in genetic factors
Family studies
Twin studies
Adoption studies
Who tested family studies
Gottesman
What did gottesman find
Children with 2 schizo parents have a concordance rate of 46%
Children with one schizo parent 13%
Sibling 9%
Conclusion of family studies
Schizo is more common among biological relatives of a person with schizo and the closer the rel the greater the risk
Therefore biological relations could be an explanation
Who tested twin studies
Joseph
What did joseph do and find
Concordance rate of mono zygotic (fraternal) twins at 40%
7% for dizygotic (similar) twins
What is the theory for the twin studies
If monozygotic twins are more concordant than dizygotic twins in terms of schizo then this suggests greater similarity is due to genetic factors
Conclusion for twin studies
Findings support view that genetic factors could be used to explain cz of the higher concordance rate of schizo in monozygotic twins than dizygotic twins
What is concordance rate
Similar to similarity rate
What is monozygotic twins
And dizygotic twins
Identical twins who share 100% of their genes
Fraternal twins who share 50% of their genes
Who tested adoption studies
Tienari et al
What did tienari et al do and find
Tested genetic and environmental influences for schizo using genetically related indvs
6.7% of the adoptees with a schizo biological mum also recieved a diagnosis of schizo
3-2% of adoptees to a non schizo mum recieved a diagnosis of schizo
Conclusion of adoption studies
Genetic liability to schizo confirmed despite genetically related indvs being reared apart (different environments)
What are the 3 section of evidence for of the dopamine hypothesis
Amphetamines
Anti psychotic drugs
Parkinsons disease
What is the dopamine hypothesis
4 points
Dopamine is a neurotransmitter
Messages from neurones that transmit dopamine fire too easily or too often leading to characteristics of schizo
Schizo have abnormally high numbers of D2 receptors on receiving neurones resulting in more dopamine building and therefore more neurones firing
Dopamine neurones play a role in guiding attention, so disturbances lead to problems with attention, perceptipn& thought
Role of amphetamines
A dopamine agonist
Stimulates nerve cells containing dopamine
Causes the synapse to be flooded with the neurotransmitter
What are amphetamines
A drug
How do we know amphetamines support hypothesis
Large doses of the drug can cause the characteristic hallucinations and delusions of a schizo episode
Role of Anti psychotic drugs
Dopamine antagonists
Block the activity of dopamine in the brain
Reduce stimulation of the dopamine system
How do we know anti psychotics support hypothesis
They eliminate and alleviate symptoms of schizo eg hallucinations and delusions
Supported view that dopamine is a contributory factor in Dev of schizo
How does Parkinsons disease support hypothesis
Low levels of dopamine are found I people with park is ons disease and when people took 5 he drug L-dopa to raise their dopamine levels they Dev symptoms of schizo
