Drug therapy Flashcards
what do drug studies show
- when normal people take amphetamine, they can experience hallucinations and delusions.
- drugs that reduce dopamine decrease the likelihood of people with schizophrenia having hallucinations and delusions.
according to the dopamine hypothesis, what would we expect to find when people with schizophrenic, who are all experiencing hallucinations and delusions, are a drug that reduces their dopamine levels?
all patients would experience a reduction in positive symptom like hallucinations and delusions.
how is a study by Noll limitation of the dopamine hypothesis
-Noll reviewed previously conducted drug studies.in theses studies, people with schizophrenia were given dugs that reduced dopamine levels. in the studies, the positive symptoms of people with schizophrenia were monitored.
what are the findings of the Noll’s study
- the results show a limitation of the dopamine hypothesis.
- the study suggests that high levels of dopamine in the mesolimbic pathways system are not the only cause of positive symptoms.
- 1/3 of patients, dopamine reducing drugs did not prevent positive symptoms of schizophrenia
what are the limitations of the dopamine hypothesis
- drugs that decrease dopamine levels don’t always prevent hallucinations and delusions.
- the evidence supporting the hypothesis isn’t always conclusive
what is the name of the drug that increases dopamine levels, leading to the experience of hallucinations and delusions in otherwise healthy people
amphetamine
what is a post-mortem examination
a detailed examination of the brain after a person has died
what did Montcrieff conclude that evidence supporting the dopamine hypothesis is inconclusive?
- drugs that increase dopamine like amphetamine also increase the levels of other neurotransmitters, so we can’t be sure that it is the increased dopamine that it causing these symptoms
- some post-mortem studies reported increased levels of dopamine in the mesolimbic pathway, but other studies reported no difference compared to the controlled brains.
what neurotransmitters does amphetamine also increase
serotonin and noradrenaline
name the researcher that criticised the dopamine hypothesis by finding that amphetamine also increases noradrenaline and serotonin alongside dopamine
Montcrieff
name the researcher that criticised the dopamine hypothesis by pointing out that not all people with schizophrenia experience positive symptoms because of high dopamine levels
Noll
describe the results of the review and explain what is meant by positive symptoms of schizophrenia ?
Noll found that across the studies, 33% of patients did not experience a reduction in positive symptoms after being administered a drug that reduced dopamine levels. This suggests that a majority of people experience positive symptoms because of high levels of dopamine in the mesolimbic system. However, this also suggests that high levels of dopamine are not the only cause of positive symptoms, because the drugs were not effective on 100% of patients.
what have post-mortem studies shown about dopamine in the brains of people with schizophrenia?
the brains of people with schizophrenia do not always have increased levels of dopamine when compared to the control group
what are positive symptoms like hallucinations and delusions caused by
high levels of dopamine in the mesolimbic pathway
how do drugs that reduce the positive symptoms of schizophrenia affect the brain?
they reduce the dopamine levels
what is the biological treatment for schizophrenia?
antipsychotics
what affect does antipsychotics medication have on the brain?
it reduces dopamine levels
where is dopamine released
dopamine is a type of neurotransmitter released by the pre-synaptic terminal
what happens when dopamine is released ?
when dopamine is released, it travels across the synaptic cleft to the post-synaptic terminal ,where it binds to post synaptic receptors