dopamins hypothesis schiz Flashcards
what does the dopamine hypothesis believe?
that schizophrenia is caused by a chemical imbalance in the brain linked to the nt dopamine
what does the hypothesis state?
the brains of schiz patients produces more dopamine, dopamine receptors having higher activity
is schiz to do with increased dopamine or decreased levels?
increased
what does the recent version of the theory state?
centres around hypersensitivity of certain dopamine receptors (d2) which means patients with the disorder are likely to overreact in the presence of dopamine
what does hypersensitivity of dopamine receptors cause?
patients to over react in the presence of the nt
what is dopamine
chemical messenger related to out ability to feel pleasure,attention and motivation
where is the an increased amount of d2 receptors?
the mesolimbic pathway
which symptoms are the d2 receptors linked to?
positive
where is there a decreased amount of d1 receptors?
the mesocortical system
what does the mesocortical system link?
the frontal lobes adnthe midbrain
what symptoms does a reduced amount of d1 receptors cause?
negative
how does sensitivity to dopamine arise?
lots of ways from genetics to brain lesioning
why are there different amount of dopamine receptors in different areas of the brain?
development of certain receptors in one area may inhibit their development in another area
what does a lack of dopamine activity in the prefrontal cortex cause?
excess production in the striatum
what did carlsson et al investigate?
whether it was just dopamine involved in the development or whether other nt played a role
what did carlsson suggest?
dopamine levels may be a result of changed somewhere else in the brain, dopamine levels compensatory system
what other nt may be involved?
glutamate
how is the regulation of dopamine controlled by glutamate?
glutamate acts as accelerators and breaks
how do experience a normal state?
equal amount of both nt
what antagonist were animals treated with?
NMDA
what happened when animals were treated with NMDA?
showed psychotic symptoms
lack of glutamate
how is serotonin linked to schiz?
causes negative symptoms
what is strength to do with drugs?
drugs given to schiz often work by blocking dopamine receptors, less is taken up
what is a strength involving parkinsons?
parkinsons sufferers are given levopoda and experience psychotic symptoms
what is levopoda?
a drug given to parkinsons sufferers that adds dopamine
how is the dopamine theory linked to genes?
genes are found in people with schiz that increase the production of dopamine
what brain differences do those with schiz have?
they have grey matter and differences in front and temporal lobes which have been linked to sensitivity of dopamine at an early age
why is it a strength that the glutamate hypothesis links to dopamine?
it creates a link between the two, building a body of knowledge which further adds to its scientific credibility
what did carlson say that is a weakness?
he said that using brain scans to look at the differences humans are likely to feel pressure and respond differently especially in presence of a mental disorder so results likely to lack validity
how can differences in neurotransmitters be assessed?
through brain scans, monitoring the activity in the brain
valid reliable
