biological therapy for schizophrenia Flashcards
(14 cards)
`most common treatment for Sz
antipsychotic drugs
what can antipsychotics be divided into
typical or atypical/second-generation
describe typical antipsychotics
- around since 1950s
- eg. chlorpromazine which is taken as tablets, syrup or injection
- if taken orally, administered daily up to max of 1000mg
- doses are smaller initially & for most increases to 400-800mg
- typical prescribed doses decreased over last 50 years (liu & de hann 2009)
why are typical antipsychotics described as dopamine antagonists
- strong association with dopamine hypothesis
- work by acting as antagonists in dopamine system
- block dopamine receptors in synapses in brain = reduces acton of dopamine
- initially when taking chlorpromazine dopamine levels build up, but its production is reduced
- this dopamine-antagonist effect normalises transmission in key areas of the brain = reduces symptoms eg. hallucinations
sedation effect of typical antipsychotics
- chlorpromazine is an effective sedative
- related to efffect on histamine receptors
- often used to calm individuals with Sz but also other conditions
- syrup absorbed faster than tablets so preferred
describe atypical antipsychotics
- used since 1970s
- aim was to maintain/improve effectiveness of drugs in suppressing symptoms of psychosis & minimise side effects
- range of atypical antipsychotics & don’t all work in same way
describe clozapine as an example of an atypical antipsychotic
- developed in 1960s & first trialled 1970s (withdrawn for while after deaths from agranulocytosis until 1980s)
- more effective than typical antipsychotics
- used when other treatments failed
- those taking it have regular blood tests
- not available as injection (potentially fatal side effects)
- daily dosage is lower than chlorpromazine = 300-450mg daily
name 2 atypical antipsychotics
- clozapine
- risperidone
how does clozapine work
- binds to dopamine receptors (same way as chlorpromazine) but also acts on seretonin & glutamate receptors
- improves mood & reduces depression/anxiety
- may improve cognitive functioning
- mood-enhancing effects means it’s sometimes prescribed when individuals at high risk of suicide (30-50% of those with Sz attempt suicude at least once)
describe risperidone as an example of an atypical antipsychotic
- more recently developed (since 1990s)
- developed to produce drug as effective as clozapine but less serious side effects
- (like chlorpromazine) it can be taken as tablets, syrup or injection (lasts ~2 weeks)
- small does initially given & built up to typically 4-8mg daily (max 12mg)
how does risperidone work
- binds to dopamine & seretonin receptors
- binds more strongly to dopamine receptors (than clozapine) = effective in much smaller doses
AO3 +) evidence to support effectiveness of antipsychotics
E:
- thornley et al. (2003) reviewed studies comparing effects of chlorpromazine to control conditions
- data from 13 trials with 1121 participants showed chlorpromazine associated with better overall functioning/reduced symptom severity compared to placebo
- (atypical antipsychotics) meltzer (2012) concluded clozapine is more effective than typical antipsychotics/other atypical antipsychotics, and it’s effective in 30-50% of treatment
T: shows antipsychotics work
AO3 -) counterpoint to evidence for effectiveness of antipsychotics
E:
- healy (2012) suggested flaws with evidence
- most studies show short-term effects & some successful trials have data published multiple times (exaggerates evidence base)
- antipsychotics has powerful calming effects, so easy to demonstrate positive effects on those experiencing Sz = not the same as reducing severity of psychosis
T: means evidence base for antipsychotic effectiveness is less impressive than it appears
AO3 -) serious side effects
E:
- typical antipsychotics associated with many side efffects (eg. dizziness, agitation, sleepiness, stiff jaw, weight gain & itchy skin)
- long-term use can cause tardive dyskinesia (causes involuntary facial movements) = due to dopamine over-sensitivity
- most serious side effect is neuroleptic malignant syndrome (NMS) resulting in high temp, coma, delirium & can be fatal = due to drugs blocking dopaminee in hypothalamus
T: means antipsychotics can do harm as well as good & individuals who experience these may avoid treatments
