Biological therapies for schizophrenia Flashcards
What is the most common treatment for SZ?
antipsychotic drugs
How can antipsychotics be taken?
tablets, syrup, injection
When are antipsychotic injections used?
When there are patients who are at risk of not taking their medications; would be given every 2-4 weeks
What are the two main types of antipsychotics?
atypical (novel), typical (conventional)
What type of schizophrenia are typical antipsychotics better for?
Type 1 as it addresses positive symptoms more
What explanation of SZ are typical antipsychotics more linked to?
Liked to the dopamine hypothesis (hypedopaminesia)
How do typical antipsychotics work?
they are dopamine antagonists, reducing the action of dopamine binding to D2 receptors on the postsynaptic neuron, blocking the transmission of dopamine
by normalising levels of dopamine transmission in the m_________ dopamine p______, this is thought to reduce ________ symptoms
by normalising levels of dopamine transmission in the mesolimbic dopamine pathway, this is thought to reduce positive symptoms
What is the main typical antipsychotic drug?
Chlorpromazine
What else is chlorpromazine used for?
A sedative used to calm patients
How is chlorpromazine faster absorbed as opposed to tablets?
Syrup
What is the maximum dosage for chlorpromazine?
1000mg
What type of schizophrenia are atypical antipsychotics better for?
Type 2 schizophrenia as there are more negative symptoms
When did atypical antipsychotics become available?
1970s
How were atypical antipsychotics meant to work as opposed to typical antipsychotics?
Meant to improve upon the effectiveness of typical antipsychotics and minimise side effects that were occurring. Also worked well on negative symptoms and cognitive impairment (suitable for treatment-resistant patients)
What are the similarities in the way typical and atypical antipsychotics work?
They both block D2 receptors
What are the differences in the way typical and atypical antipsychotics work?
Atypical only temporarily occupy the D2 receptors and then rapidly dissociate to allow normal dopamine transmission - this is thought to be responsible for the lower levels of side effects
What are the 3 most known atypical antipsychotics?
Clozapine, Risperidone and Olanzapine
What is the time line of Clozapine?
Developed in 1960s, trailed in 1970s. (Withdrawn due to deaths from blood condition). 1980s - discovered more effective than typical antipsychotics. (Now used as an alternative)
What blood condition were people dying from due to clozapine?
Agranulocytosis
How is Clozapine administered?
As a syrup or tablet at 300-450mg a day
why isn’t clozapine administered as a injection?
Because of its fatal side effects
How does Clozapine work?
Binds to dopamine, serotonin and glutamate receptors
By the drug Clozapine working on other _________________ this helps to reduce d_________ and a______ and improve c________ functioning.
By the drug Clozapine working on other neurotransmitters this helps to reduce depression and anxiety and improve cognitive functioning.
Why is clozapine given to people who are at high risk of suicide?
because it improves mood
What % of sz patients are likely to commit suicide?
30-50%
When did risperidone emerge and why?
In the 1990s as an attempt to reduce the serious side effects of clozapine
How is risperidone administered?
As a syrup, tablet or injection; given 4-8mg and max 12mg
How does Risperidone work?
binds to dopamine and serotonin receptors and is better at binding than clozapine so less side effects and smaller doses
What are the strengths of drug therapy?
- Research evidence for the effectiveness of typical antipsychotics (Thornley et al (2003)) - Research evidence for the appropriateness of atypical antipsychotics (Meltzer (2012)) - Research evidence for lower relapse rates (Leucht et al (2012))
What are the studies that found research support for drug therapy of sz?
Thornley et al (2003), Meltzer (2012), Leucht et al (2012)
What did Thornley et al (2003) look at?
The moderate effectiveness of typical antipsychotics
What was the first method of Thornley et al (2003)?
Compared use of chlorpromazine to placebos from data of 13 trials with 1121 pps
What were the results of Thornley et al’s (2003) first study?
Chlorpromazine was associated with reduced symptoms and better overall functioning
What was the method of Thornley et al’s (2003) second study?
Three trials with 512 pps
What were the results of Thornley et al’s (2003) second study?
Relapse rate was lower when chlorpromazine was taken
What was concluded from Thornley et al’s (2003) research ?
Typical antipsychotics are effective in reducing the symptoms of SZ compared to a placebo
What did Meltzer (2012) conclude?
Clozapine is more effective than typical antipsychotics and other atypical antipsychotics and was seen as effective in 30-50% of cases where typical antipsychotics failed
What research did Leucht et al (2012) conduct on relapse rates in antipsychotics?
Meta analysis of 65 studies from 1959-2011 with 6000 patients. some given placebos and 64% relapsed on these whereas only 27% relapsed on antipsychotics
What are the weaknesses of drug therapy for SZ?
- Side effects - Issues with evidence for drug effectiveness by Healy (2012) - Ethical issues - not understood how they work
What are the side effects for typical antipsychotics?
Dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin or Tardive dyskinesia, NMS
tardive dyskinesia
Caused by dopamine super sensitivity and is involuntary facial movements such as grimacing blinking and lip smacking
What is the most serious effect of typical antipsychotics?
NMS, Neuro malignant syndrome
Neuro malignant syndrome (NMS)
high temperature, delirium, coma and death. occurs in 0.1-2%
What evidence did Healy (2012) find against the effectiveness of drugs for sz?
Some successful drug trials have been published more than once exaggerate the effectiveness and may just be a calming effect
What are the ethical issues of drug therapy?
Consent
