Biological Therapy For Schizophrenia Flashcards
What are antipsychotics?
- Drugs used to reduce the intensity of symptoms in particular the positive symptoms, of psychotic condirions like schizophrenia
What are typical antipsychotics?
- The first generation of drugs for schizophrenia & other psychotic conditions have been used since the 1950s
- They work as dopamine antagonists & include chlorpromazine
the main typical one is chlorpromazine
How is chlorpromazine taken?
- Can be taken as tablets/syrup or by injection
- If taken orally it is administered daily up to a maximum of 1000mg
- Although initially doasge is much smaller & for most people dosage is gradually increased to a maximum of 400-800mg
- Patients need to stay on the drug in order for it to be effective
There is a strong association between use of typical antipsychotics like chlorpromazine & dopamine hypothesis, why is this?
- Typical antipsychotics like chlorpromazine work be acting as antagonists in the dopamine system
- Dopamine antagonists work by blocking dopamine receptors in the synapse of the brain, reducing the action of dopamine
- Initially when individual starts taking chlorpromazine dopamine levels build up , but then its production is reduced
- According to dopamine hypothesis of schizophrenia this dopamine-antagonist effect normalises neurotransmission in key areas of the brain, reducing symptoms like hallucinations
Antagonists are chemicals which reduce the action of a neurotransmitter
What is the sedation effect that typical antipsychotics have?
- ASWA having antipsychotic properties, chlorpromazine is also an effective sedative
- This is belived to be related to its effect on histimine receptors but it is not fully understood how this leads to sedaton
- Chlorpromazine is often used to calm individuals not only w schiz but w other conditions asw
- It may also help to reduce symptoms of schiz enough to help patient engage in talking therapy (CBT). Therefore may be useful in a combined treatment programme, rather than a single treatment programme
What are atypical antipsychotics?
- Drugs for schizophrenia developed after typical antipsychotics
- Target a range of neurotransmitters such as dopamine & serotonin
What are the two A-typical antipsychotics?
- Clozapine
- Risperidone
What is the history behind Clozapine?
- Was developed in 1960s & first trialled in early 1970s
- Was withdrawn for a while in 1970s following deaths by some patients from blood condition aranulocytosis
- However when it was discovered to be more effective than typical antipsychotics Clozapine was remarketed as a treatment for schizophrenia to be used when other treatments failed- still used in this way today, w people taking regular blood tests to make sure they arent developing aranulocytosis.
What does Clozapine actually do?
- Binds to dopamine receptors in the same way chlorpromazine does, but in addition it acts on serotonin & glutamate receptors
- It is believed that this improves mood & reduces depression & anxiety in patients & may improve cognitive functioning
- Mood-enhancing effects of clozapine mean it is sometimes perscribed when an individual is considered at high risk of suicide
- This is important as 30%-50% of people w schizophrenia attempt suicide at some point
What are the side effects of Clozapine?
- Angranulocytosis (decrease in white blood cells which can result in death
- Weight gain
- Increased risk of:
Stroke
Diabetes
Blood clots
What did Melter 1999 find?
- 33% of patients who did not respond to neuroleptics showed improvement with atypical drug Clozapine
Marder (1996)
- Also found clozapine to be effective in approx 30%-61% of patients resistant to typical antipsychotics
What is Risperidone?
- More recently developed antipsychotic
- Was developed in attempt to produce a drug as effective as clozapine but without its serious side effects
- Like Clozapine risperidone is believed to bind to dopamine & serotonin receptors
- Risperidone binds more strongly to dopamine receptors than clozapine & is therefore effective in much smaller doses than most antipsychotics
Give one strength of biological therapy for schizophrenia.
- Evidence to support their effectivness
There is large body of evidence to support idea that both typical & atypical antipsychotics are at least moderately effective in tackling the symptoms of schiz
Ben Thornley et al (2003) - Reviewed studies comparing effects of chlorpromazine to control conditions
- Data from 13 trials w a total of 1121 ppts showed that chlorpromazine was associated w better overall functioning & reduced symptom severity compared to a placebo
ALSO EVIDENCE FOR ATYPICAL ANTIPSYCHOTICS
Herbet Meltzer (2012)
- Concluded that clozapine is more effective than typical antipsychotics & other atypical antipsychotics & that it is effective in 30%-50% of treatment resistant cases where typical antipsychotics have failed
This means that as far as we can tell antipsychotics work
Give one limitation of biological therapy for schizophrenia.
OL: Is treatment resistance
- According to research, around 30% of individuals w schiz do not respond to typical or atypical antipsychotic drugs.
- This challenges dopamine hypothesis, as it suggests that schizophrenia may not always be caused by excess dopamine activity.
- Instead, other factors such as glutamate dysfunction - - Limiting effectiveness of biological treatments & highlights need for alternative approaches, e.g such as CBT or newer pharmacological developments.
