L4 - Biological Treatments For SZ Flashcards
1
Q
What is the most common treatment for SZ?
A
- Drugs - specifically antipsychotic drugs
- can be tablet, syrup, injection
- injections tend to be given to patients at risk of not taking meds, given every 2-4 weeks
- to control SZ symptoms, nearly all patients are first given antipsychotics either for short/long time depending on symptoms
- when the patient is stable, sometimes they are also given psychological therapies e.g. CBT
2
Q
2 main types of antipsychotic drugs
A
- Typical (traditional or 1st gen antipsychotics)
- Atypical (2nd gen antipsychotics)
3
Q
Typical antipsychotics
A
- have a strong link to the dopamine hypothesis explanation of SZ
- drugs are dopamine antagonists and work by reducing the effects of dopamine and thus reduce the symptoms of SZ.
- drugs bind to dopamine receptors (particularly the D2 receptors in the mesolimbic dopamine pathway), thus blocking their action, reducing the actions of dopamine & the positive symptoms of SZ.
- they reduce levels of excitation via dopamine in the synapses
4
Q
Typical antipsychotic examples
A
Chlorpromazine, fluphenazine, haloperidol
5
Q
Chloropromazine
A
- Typical antipsychotics have been around since the 1950s, can be taken as a tablet, syrup or injection.
- it is also an effective sedative and was actually used to calm patients not only with SZ but also other conditions.
- when schizophrenic patients are first admitted to hospital, they are given chlorpromazine to calm their nerves.
- it is faster absorbed in syrup form rather than tablet – hence it being an effective sedative.
- The maximum dosage for the tablet would be 1000mg.
- when given first, the dosage would be much smaller but gradually increased from about 400mg to 800mg.
- When the patient would first take Chlorpromazine, dopamine levels would build up but then the production of dopamine would reduce.
- it would therefore work to normalize the dopamine production and transmission – this in term would then reduce the symptoms of SZ such as hallucinations.
6
Q
Atypical antipsychotics
A
- emerged in the 1970s and were used to improve upon the effectiveness of typical antipsychotics and minimize the side effects that were occurring when patients were given typical antipsychotics.
- also have a beneficial effect on negative symptoms and cognitive impairment are suitable for treatment-resistant patients
- work like typical antipsychotics by blocking D2 receptors, but they only temporarily occupy the D2 receptors and then rapidly dissociate to allow normal dopamine transmission
- it is this rapid dissociation that is thought to be responsible for the lower levels of side effects
7
Q
Atypical antipsychotics
A
- emerged in the 1970s and were used to improve upon the effectiveness of typical antipsychotics and minimize the side effects that were occurring when patients were given typical antipsychotics.
- also have a beneficial effect on negative symptoms and cognitive impairment are suitable for treatment-resistant patients
- work like typical antipsychotics by blocking D2 receptors, but they only temporarily occupy the D2 receptors and then rapidly dissociate to allow normal dopamine transmission
- it is this rapid dissociation that is thought to be responsible for the lower levels of side effects
8
Q
Examples of atypical antipsychotics
A
Quetiapine, clozapine, risperidone and olanzapine
9
Q
Clozapine
A
- developed in 1960s, trialed in the 1970s.
- due to patients dying from a blood condition called agranulocytosis after taking clozapine, it was withdrawn.
- it then came back in the 1980s seen as a more effective treatment for SZ rather than typical antipsychotics.
- Clozapine is used as an alternative treatment for SZ if the typical antipsychotic drugs failed to work.
- However, patients are given regular blood tests to make sure that they don’t have agranulocytosis.
- Because of its fatal side effects, clozapine is not available as an injection but only in syrup or tablet.
- The dosage given to patients is between 300 – 450 mg per day – much lower than chlorpromazine.
- Clozapine works by binding to dopamine receptors but in addition, acts on serotonin and
glutamate receptors. - drug working on other neurotransmitters, this helps to reduce depression and anxiety and improve cognitive functioning.
- as clozapine doesimprove mood, it is generally given to patients who are at high risk of suicide.
- This is important as research has shown that between 30-50% of patients with SZ are likely to attempt suicide.
10
Q
Risperidone
A
- drug emerged in the 1990s as an attempt to reduce the serious side effects of clozapine but still be as effective as clozapine.
- Risperidone can be taken as syrup, tablets or injection.
- Patients are given a dose of about 4-8mg and up to a maximum of 12mg.
- Risperidone like clozapine works by binding to dopamine receptors but works better in binding to dopamine receptors than clozapine leading to less side effects.
- As a result, much smaller doses are required of risperidone.
- Evidence also suggests that this leads to fewer side effects than most other
antipsychotics
11
Q
Evaluation of drug therapy
A
strengths
- research support for moderate effectiveness
- research support for atypical drugs
- lower relapse rates
weaknesses
- side effects
- problems with evidence
- ethical issues
- don’t know why they work
12
Q
Research support for moderate effectiveness
A
- There is research evidence to support the moderate effectiveness of typical antipsychotic drugs in treating SZ.
E.g. Thornley et al (2003) compared the use of chlorpromazine (typical antipsychotics) with a placebo. - Data from 13 trials with a total of 1121 pps showed that chlorpromazine was associated with reduced symptoms and better overall functioning.
- Furthermore, data from three trials with a total of 512 pps showed that relapse rate was also lower when chlorpromazine was taken.
- This study this shows that typical antipsychotics were effective in reducing the symptoms of SZ compared to a placebo showing that drug therapy is appropriate in treating SZ
13
Q
Research evidence for atypical drugs
A
- research evidence to support the appropriateness of atypical antipsychotics.
- In a review by Meltzer (2012), he concluded that Clozapine (atypical antipsychotics) is more effective than typical antipsychotics and other atypical antipsychotics in treating SZ.
- In fact Clozapine was seen as effective in 30-50% of cases where typical antipsychotics had failed.
- This study shows that use of clozapine as a treatment for SZ is a very appropriate drug as Meltzer clearly showed especially when other drugs failed!
- Interestingly, a number of studies have compared the effectiveness of clozapine and risperidone but results have been inconclusive suggesting that some patients respond better to one drug than the other and also supporting the idea that SZ is a complex psychotic disorder
14
Q
Relapse rates lower
A
- There is also research evidence to support the fact that relapse rates are much lower when patients take antipsychotic drugs (both typical and atypical) as opposed to placebos.
- Leucht et al. (2012) carried out a meta-analysis of 65 studies, published between 1959 and 2011, and involving nearly 6000 patients.
- Some patients were taken off their antipsychotic medication and given placebos instead.
- Within 12 months, 64% of those patients who had been given the placebo relapsed whereas only 27% relapsed when on antipsychotic medication.
- The results of this study clearly show that antipsychotic medication is both effective and appropriate in preventing a schizophrenic patient from relapsin
15
Q
Side effects
A
- biggest weakness of drug therapy in treating SZ is the serious side effects ranging from mild ones to fatal ones.
- For typical antipsychotics, the side effects include: dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin.
- A more profound side effect can result in ‘tardive dyskinesia’ which is caused by dopamine supersensitivity and manifests as involuntary facial movements such as grimacing, blinking and lip smacking.
- The most serious side effect of typical antipsychotics is NMS (neuro malignant syndrome – area of the brain associated with the regulation of a number of body systems) – which could lead to high temperature, delirium and coma and can cause death
– this may occur in between 0.1% - 2% of schizophrenics. - Whereas atypical antipsychotics were developed to overcome these side effects.
- However, side effects do exist for atypical antipsychotics such as Clozapine thus regular blood tests need to be taken of the patients to test for early signs of agranulocytosis (a rare blood condition where the production of white blood cells is prevented – leads to problems with immunity)
