Biological therapy for schizophrenia Flashcards
Typical antipsychotics
Biological therapy
1950s
Chlorpromazine
Can be taken as tablets, syrup or injection
Max does is 400-800mg
Typical prescribed doses have declined over last 50 years (Liu & de Haan, 2009)
How do typical antipsychotics function as dopamine antagonists?
Biological therapy
Chlorpromazine works by acting as antagonist in dopamine system
Dopamine ntagonists work by blocking dopamine receptors, reducing action of dopamine
Initially, dopamine levels will build up but then prodcution is reduced
Reduces symptoms like hallucinations
How do typical antipsychotics have a sedation effect?
Biological therapy
Believed to be related to chlorpromazine’s effect on histamine receptors
Used to calm inidividuals with conditions otehr than SZ
Syrup absorbs faster than tablets so it tends to be given when used as a sedative
Atypical antipsychotics
Biological therapy
1970s
Aim was to maintain or improve effectiveness of drugs in suppressing symptoms and minimise side effects
Range of different atypical antipsychotics and don’t all work in same way
Clozapine (Atypical)
Biological therapy
Caused deaths in 1970s after deaths of patients from blood condition (agranulocytosis) so withdrawn
In 1980s found to be more effective than typical antipsychotics so remarketed as treament for SZ
Still used today - regular blood tests
Not avalible as injection due to fatal side effects
Daily dosage is 300-450mg
How does clozapine work?
Biological therapy
Binds to dopamine receptors in say way as chlorpromazine but also acts on serotonin and glutamte
Believed this helps to improve mood and reduce depression & anxiety
Mood-enhancing effects mean that it is sometimes prescribed when an individual is at high risk of suicide
30-50% of people with SZ attempt suicide at some point
Risperidone (Atypical)
Biological therapy
1990s
Developed to produce drug as effective as clozapine without serious side effects
Can be taken as tablet, syrup or injection
Daily dose starts at 4-8mg and maxes at 12mg
Believed to bind to DA and serotonin receptors
Binds more strongly to DA receptors than clozapine so is more effective in smaller doses
Leads to fewer side effects than any other antipsychotics
Evidence for effectiveness
Biological therapy
Strength
Thornley et al (2003) reviewed studies comparing effects of chlorpromazine with control conditions
Data from 13 trials (1121 ppts) showed chlorpromazine had better overall functioning and reduced symptom severity as compared to placebo
Meltzer (2012) clozapine is more effective than typical antipsychs and other atypical antipsychs
Effective in 30-50% of treatment-resistant cases where typical have failed
Therefore, antipsychs work
Counterpoint (Evidence for effectiveness)
Biological therapy
Healy (2012) suggested flaws with evidence for effectiveness
Most studies are short-term effects and successful trials were published many times, exaggerating size of evdience base
Antipsychs have calming effect - easy to demonstrate that they have a posotive effect on people with SZ
Not same as saying they reduce severity of psychosis
Therefore, evidence base is not as impressive
Side effects
Biological therapy
Limitation
Typical antipsychs - dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin
Long term can result in tardrive dyskinesia
Most serious of typical is neuroleptic malignant syndrome - caused when drug blocks DA action in hypothalamus
NMS results is high temp, delirium and coa
Therefore, antipsychs can do a lot of harm as well as good and individuals should be aware of this
Mechanism unclear
Biological therapy
Limitation
Understanding of how antipsychs work is linked to OG DA hypothesis
We now know OG DA hypothesis is not complete explanation for SZ - DA levels in other parts of brain are too low
If this true, most antipsychs shouldn’t work
Adds to arguement that they are ineffective
Therefore, some of the antipsychs aren’t the best treatment
Chemical cosh
Biological therapy
Antipsychs have been used in hospitals to calm people with SZ and make them easier to work with, rather than for benefits to people themselves (Moncrieff, 2013)
However, calming people distressed by hallucinations & delusions makes them feel better and allows them to engae with other treaments and services
