bipolar explanation for schizophrenia Flashcards
what have family studies shown
shown that there is a strong relationship between the degree of genetic similarity and the shared risk of schizophrenia.
who conducted large scale family studies
Irving Gottesmans
what did Irving gottesman do
large-scale family study
found that someone with an aunt had an increased 2% chance of developing schizophrenia.
sibling = 9%
identical twin = 48%
what did early research look into regarding candidate genes
a single genetic variation.
what has more modern research concluded in terms of candidate gene
that a number of different genes are involved.
what is schizophrenia described as
polygenetic.
what dose polygenetic mean
a number of different genes are involved.
what are the most likely polygenetic genes to be involved in schizophrenia
coding for neurotransmitters including dopamine.
what did ripke et al do
combined all previous data from genome wide studies of schizophrenia.
37000 people with schizophrenia compared to 113000 controls
what did ripket et al find
108 separate genes were associated with a slightly increased risk of schizophrenia
also aetiologically heterogeneous.
what is aetiologically heterogeneous.
different combinations of factors, including genetic variation, can lead to the condition.
describe the role of mutation in schisophrenia
Schizophrenia can also have a genetic origin in the absence of a family history because of mutation in parental DNA.
what can causer mutations of parental DNA
radiation, poison or viral infection
what did brown et al find
that evidence for mutation comes from positive correlations between parental age and risk of schizophrenia.
0.7% father’s under 25
2% in father’s over 50.
define neural correlates
Patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience.
what is the best know correlate of schizophrenia
dopamine. - because it is featured in the functioning of brain systems related to the symptoms of schizophrenia.
what is the original dopamine hypothesis
schizophrenia might be the result of high levels of dopamine in subcortical areas of the brain.
example: excess of DA receptors in pathways from sub cortex to brooks area.
what is the updated version of the dopamine hypothesis
proposed that abnormally low levels of dopamine in the prefrontal cortex ( cortical hypodopaminergia )
could explain negative symptoms of schizophrenia.
Kenneth Davis et al
what has also been suggested in terms of cortical hypodopaminergia.
leads to subcortical hyperdopaminergia –
so both high and low levels of dopamine in different brain regions are involved.
what dose current versions of the dopamine
hypothesis try to explain.
the origin of abnormal Dopamine functions
what did (Howes et al., 2017). propose
They propose that genetic variations and early experiences of stress make some people more sensitive to cortical hypodopaminergia and hence subcortical hyperdopaminergia
