Paper 3 - Schizophrenia - Biological And Neural Explanations Flashcards
What are the 3 Biological Explanations?
Genetic Vulnerability
Dopamine Hypothesis
Neural Correlates
What are the different sub categories of Genetic Vulnerability
Family studies
Twin studies
Adoption studies
Candidate Gene
Explain family studies?
Gottesman (1991) Family studies
His findings showed that the greater the degree of genetic relatedness, the greater risk of developing schizophrenia
But identical twins were only about 48% so there is still a great environmental impact
Explain twin studies?
Twin studies
Gottesman and shields (1962) found that the concordance rate for schizophrenia in MZ twins was 48% compared for 17% for DZ twins
Suggesting that schizophrenia has a genetic basis
Joseph (2004) showed a concordance rate of 40.4% for MZ and 7.4% for DZ
Explain the first adoption study?
Heston (1966) compared 47 adopted children whose biological mothers had schizophrenia with a control group with no family history of schizophrenia
0 in the control group was diagnoses with schizophrenia 16% of the offsprings of the sample were diagnoses
explain the second adoption study?
Tienari (2000)
Found that 11% of 164 adoptees whose mothers had schizophrenia also had schizophrenia
Explain the candidate Gene?
Schizophrenia is thought to be polygenic (many genes make up the disorder)
Ripke (2014) completed a study combining all data from a genome wide study of schizophrenia
37000 patients were compared to 113,000 controls
108 separate genetic variations were associated with an increased risk of schizophrenia
What is the word for many genes being the cause of something?
Polygenic
What is important to remember about the dopamine hypothesis?
It was originally just hyper and hen adapted to include hypo
What is the theory of the Dopamine Hypothesis?
This theory claims that excessive amounts of dopamine or an oversensitivity of the brain dopamine is the cause of schizophrenia.
So messages from neurons that transmit dopamine fire too easily or too often, leading to the characteristic symptoms of schizophrenia.
However, it was adapted to include the effects of lower levels of dopamine
What is the general overview of the dopamine hypothesis?
An excess of the neurotransmitter dopamine has been implicated in the symptoms of schizophrenia
Hyperdopaminergia in the subcortex
Hypodopaminergia in the cortex
What is the ending of that long word?
Dopamine rgia
Where may hyperdopaminegia occur?
The sub cortex
Where may hypodopaminegia occur
Cortex
Explain hyperdopaminegia in the subcortex?
Higher levels of dopamine in the subcortex
So there is excess levels of dopamine receptors in Brocca’s area. This may be the cause of the disorganised speech (as brocca’s area is overexcited)
Furthermore, as there is excess dopamine in the subcortex his could explain the experience of auditory hallucinations
Explain hypodopaminegia in the cortex?
Lower levels of dopamine in the brain’s cortex
Goldman and Rakic et al (2004) identified that low levels of dopamine in the prefrontal cortex
It will increase the negative symptoms of schizophrenia as it effects thinking and decision making