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
what happens when higher levels of dopamine released in the mesolimbic system ?
more dopamine will bind to post-synaptic receptors
as a result of the increased dopamine binding to the post synaptic receptors, what happens in the post-synaptic neurons in the mesolimbic system
- more positively charged particles flow into the post synaptic neuron
- overactivity occurs in the mesolimbic system
how do antipsychotic drugs work ?
- antipsychotics prevent dopamine from binding to the postsynaptic receptors
- anti psychotics reduce the overactivity of neurons in the mesolimbic pathway
how do antipsychotic drugs affect the activity of dopamine
they decrease it
how do antipsychotic decrease the activity of dopamine
by blocking post-synaptic receptors to prevent dopamine binding to these receptors
what type of schizophrenic symptom do anti-psychotic drugs prevent?
hallucinations and delusions
what are positive symptoms of schizophrenia caused by?
according to the dopamine hypothesis positive symptoms of schizophrenia are caused by high levels of dopamine in the mesolimbic system
what is the mesolimbic system?
the group of brain regions involved in processing reward
what are the limitations of antipsychotic drugs?
- antipsychotic dugs can cause side effects in patients with schizophrenia. such as cause extra-pyramidal symptoms- where patients loose control over movements (i.e. stiff, jerky movements). and the drugs also cause other health problems like obesity, heart problems and diabetes.
- they are unable to treat negative symptoms like avoilition and speech poverty and make negative symptoms worse
what are extrapyramidal symptoms ?
where patients loose control over movements (i.e. stiff, jerky movements)
how do antipsychotic drugs reduce positive symptoms in people with schizophrenia ?
they prevent overactivity in the mesolimbic system
according to the dopamine hypothesis, negative symptoms are caused by low levels of dopamine in what area of the brain?
frontal cortex
why can’t antipsychotic drugs both unable to treat negative symptoms and potentially make them worse
Antipsychotics reduce the dopamine activity levels in all areas of the brain. Negative symptoms of schizophrenia are thought to be caused by reduced dopamine levels in the frontal cortex. So antipsychotics not only lack the ability to treat these symptoms, but could make them more intense, because they further reduce dopamine activity levels in the frontal cortex.
what do anti psychotics bind to
dopamine receptors
what can atypical antipsychotics treat that typical antipsychotics can’t
negative symptoms of schizophrenia
what do atypical and typical antipsychotics both do?
bind to dopamine receptors in order to block dopamine. atypical bind to dopamine for shorter periods of time but typical antipsychotics bind to dopamine for longer periods of time
what are traditional antipsychotics know as
typical antipsychotics
what is a meta analysis?
a combination and analysis of results of the results from multiple studies
how did Leuchts study support atypical antipsychotics
conducted a metanalysis of 65 previous studies to compare and analyse all results on the effectiveness of antipsychotic drugs
what did Leucht find
- He found that antipsychotics were more affective at treating schizophrenia than a placebo.
- he found that antipsychotic drugs led to lower relapse rates
- antipsychotics led to less severe positive symptoms
why do atypical antipsychotics lead to fewer side effects than typical antipsychotics ?
Atypical antipsychotics bind to dopamine receptors for a shorter period of time than typical antipsychotics. By allowing dopamine to still bind to the receptors from time-to-time, people who take atypical antipsychotics typically experience less side effects, because there is less disruption to dopamine activity in all areas of the brain.
what did Crossley find between atypical and typical antipsychotics ?
he found that there was no significant differences between atypical and typical antipsychotic in how effect they were at preventing symptoms. and he found that atypical antipsychotics had fewer side effects and didn’t cause extra pyramidal symptoms
what did Crossley study
meta-analysis of 15 studies on the effectiveness of antipsychotics
what is a limitation of atypical and typical antipsychotics ?
One limitation of both types of antipsychotics is that people with schizophrenia have a high likelihood of relapsing if they stop taking their medication. This is important because drugs might not be treating the underlying cause of the disorder - they may just be blocking the symptoms.
what are the differences between atypical and typical antipsychotics ?
- typical antipsychotics are unable to treat negative symptoms of schizophrenia, why atypical antipsychotics can.
- a typical have fewer side effects than typical
- typical antipsychotics bind to dopamine receptors for longer periods of time compared to atypical antipsychotics.
what is an advantage of antipsychotic drugs
An advantage is that for most sufferers, antipsychotic drugs successfully calm the effects of schizophrenia. Silverman (1987) stated that antipsychotic have beneficial side effects for some people in increasing levels of attention and information processing.
what does Silverman suggest antipsychotics?
he states that antipsychotics have beneficial side effects for some people in increasing levels of attention and information processing.
what is chlorpromazine
is probably the most widely used antipsychotic and was first used on schizophrenia patients 1952 by delay and Denver.
what did Kane suggest about Chlorpromazine
that it has been found to be more effective than the phenothiazines, helping approximately 80-85% of schizophrenia.
