Schizophrenia - Drug Therapy Flashcards
Explain typical antipsychotics
they work by acting as antagonists in the dopamine system + aim to reduce the action of dopamine - strongly associated with dopamine hypothesis
Explain how dopamine antagonists work
by blocking dopamine receptors in the synapses in the brain - reducing the action of dopamine.
Initially dopamine levels build up after taking chlorpromazine but then production is reduced.
This normalises neurotransmission in key areas of the brain, which in turn reduces symptoms like hallucinations
What effect does Chlorpromazine also have
effect on histamine receptors therefore it is also used to calm anxious patients when they are first admitted to hospital - sedation effect
give an example of a typical antipsychotic
chlorpromazine
give an example of an atypical antipsychotic
clozapine
What do atypical antipsychotics do
target dopamine and serotonin
improve the effectiveness of drugs is suppressing psychosis such as SZ and minimise side effects
What does clozapine do
binds to dopamine receptors like chlorpromazine but also acts on serotonin and glutamate receptors.
were atypical antipsychotics or typical psychotics more effective
Clozapine was more effective (atypical) as clozapine reduces depression + anxiety in patients as well as improving cognitive functioning
it also improves mood which is important as 50% of SZ patients attempt suicide
What is another atypical antipsychotic other than clozapine?
Risperidone
Why was Risperidone developed
because clozapine was involved in the deaths of some patients with a blood condition called agranulocytosis
How does Risperidone work
binds to dopamine and serotonin
Why is Risperidone more effective
it binds more strongly to dopamine and so can be used in smaller doses as it is more effective and has fewer side affects
give two studies who supports drug therapy
Thornley et al (2003) shows antipsychotics are moderately effective
Meltzer (2012) support for the benefits of atypical antipsychotics
What did Thornley et al (2003) do and find
reviewed data from 13 trials (1121 participants) + found that chlorpromazine was associated with better functioning and reduced symptom severity compared with a placebo
What did Meltzer (2012) conclude
clozapine is more effective than typical antipsychotics + that it is 30-50% more effective in treatment
Give three limitations of antipsychotics
side effects
not really effective
chemical cosh
Explain side effects as a limitation of antipsychotics
associated with dizziness, agitation,slepiness and weight gain the most serious side effect is neuroleptic malignant syndrome caused by blocking dopamine action in the hypothalamus which can be fatal due to disrupted regulation of several body systems
Explain doubts to true effectiveness using a study as a limitation of antipsychotics
Healy(2002) sugests data from successful trials have been published many times exaggerating positive effects. Also as antipsychotics have powerful calming effects it can be easy to demonstrate the + effects despite the fact it might not be effective for psychosis
What is the conclusion to Healy (2002)
This suggests the effectiveness of antipsychotics may be overestimated by much of the empirical research
Explain chemical cosh as a limitation to antipsychotics
APSYC used in hospitals to calm patients so they are easier to work with rather than benefiting the patient themselves (short term) which is recommended by NICE
However this may abuse HR and raises ethical issues in the use of APSYC in SZ
