biological therapies for schizophrenia Flashcards
what’s the most common treatment for schiz
drug therapy antipsychotic drugs
how are antipsychotic drugs taken
tablets or syrup.
those risk to not take medication avalibkle as injections every 2/4 weeks.
how ling should antipsychotic drugs be taken for
may be required short or long term.
some patients can take short course then stop w/out return of symptoms.
other require for life or recurrence of schiz.
what are the two types of antipsychotic drugs
typical (traditional)
newer atypical or second-generation drugs.
what are the typical antipsychotic drugs
around 1950s & include chlorpromazine.
strong association between typical & chlorpromazine & dopamine hypothesis.
how can chlorpromazine be taken and dosage
as tablets, syrup or injection.
orally - daily max 1000mg, initial doses much smaller gradually increase 400 to 800mg.
typical doses have declined over last 50yrs.
how do the typical antipsychotics like chlorpromazine work
by acting as antagonists in the dopamine system.
antagonist r chemicals which reduce the action of a neurotransmitter.
dopamine antagonist work by blocking dopamine receptors in the synapses of the brain, reducing the action of dopamine.
initially when patient begins taking chlorpromazine dopamine levels build up, but then its production is reduced.
according to dopamine hypothesis - this dopamine-antagonist effect normalises neurotransmitter in key brain - reduces symptoms like hallucinations
what do typical antipsychotics reduce
symptoms like hallucinations
what is chlorpromazine also useful for
effective sedative
related to its effect on histamine receptors.
chlorpromazine often used to calm patients with other conditions.
what are the atypical antipsychotics
used since 1970s.
aim in developing newer antipsychotics to improve effectiveness & reduce side effects.
antipsychotics don’t all work in same way.
early clozapine
1970s/60
developed in 1960s, first trialed in 1970s.
withdrawn in 1970s bc of deaths from blood condition - agranulocytosis.
later clozapine
1980s
in 1980s discovered to be more effective than typical antipsychotics.
clozapine remarked as treatment for schiz when all other failed.
modern day clozapine
still used today, ppl take regular blood tests to prevent development of agranulocytosis .
bc of side effects not available as injection.
daily dosage is lower than chlorpromazine.
typically 300 - 450mg a day
dosage of clozapine
300-450mg a day
how does clozapine work ??
C binds to dopamine receptors in same way chlorproxamine does.
but in addition - acts on serotonin & glutamate receptors.
what r the benefits of clozapine
this action helps improve mood & reduce depression/anxiety.
this may improve cognitive functioning.
so prescribed to patients w high risk of suicide. (30/50%)
how many schiz sufferers attempt suicide
30 to 50%
what was Risperidone aim
attempt to produce drug as effective as clozapine but w/out serious side effects.
what is risperidone
more recently developed atypical antipsychotic
been around since 1990s.
how can risperidone be taken
tablets, syrup or injection - lasts around 2 weeks.
small dose start, built up to 4-8mg max 12mg
how does risperidone work
bind to dopamine & serotonin receptors. R binds more strongly to dopamine receptors than clozapine so is more effective in much smaller doses than most antispchotics.
evidence to suggest fewer side effects than is typical
what are the 2 atypical antipsychotics
- clozapine
- risperidone
all A02 points for biological therapies
+ evidence for effectiveness
- serious side effects
- use of antipsychotics depend on dopamine hypothesis
-problems for effectiveness
A02
evidence for effectiveness
Thornley et al: reviewed a studies comparing effects of chlorpromazine to control conditions - patients received placebo.
13 trials. 1121 participants.
showed chlorpromazine better overall functioning & reduced symptoms severity.
++research supporting this^
Meltzer
A02
Meltzer research support for the effectiveness
concluded that clozapine more effective than typical & atypical.
is effective in 30-50% of treatment resistant cases where typical have failed.
seems general antipsychotics r reasonably effective, strength
A02
serious side effects
dizziness, agitation, sleepiness, stiff jaw, weight gain, itchy skin.
long term use - tardive dyslexia manifests as involuntary facial movements e.g. grimacing, blinking.
most serious - NMS neuroleptic malignant syndrome.
NMS results in high temp, delirium, coma can be fatal.
typical doses have declined NMS has become rarer. 0.1-2%
atypical developed to reduce side effects, worked (melzer)
but still exist clozapine - weakness
what’s most serious side effect of typical antispychotics
NMS
neuroleptic malignant syndrome.
NMS results in high temp, delirium, coma can be fatal.
how is NMS caused
drug blocks dopamine action in the hypothalamus, area in brain associated with the regulation of number of body systems.
A02
use of antipsychotics depend on the dopamine hypothesis
theoretical issue not practical.
evidence showing original dopamine hypothesis not complete explanation for schiz.
instead - dope levels parts of the brain other than subcortext too low rather than too high.
so not clear how antipsychotic help w schiz when they reduce dope activity. = suggests antipsychotics shldnt work.
undermine effectiveness
A02
problems with evidence for effectiveness Healy
HEALY suggested some successful trails had data published multiple X, exaggerated positive effects.
powerful calming effects-some positive effects. BUT not same as reducing severity of psychosis. & most published studies asses short term not long benefits.
& compare patients who keep taking them w those suffering withdrawal just stopped taking them.
