Biological therapy for SZ

Question 1

What is the most common treatment for schizophrenia?

Answer 1

• antipsychotic drugs

Question 2

What are the two types of antipsychotic drugs used for the treatment of schizophrenia?

Answer 2

• typical antipsychotics (first gen) > used since 1950s
• atypical antipsychotics (second gen) > used since 1970s

Question 3

How are antipsychotics use differently for different people with SZ?

Answer 3

• may be required in the short or long term
• some people can take a short cause of antipsychotics then stop use without return of symptoms
• other people may require use for life or face likelihood of relapse

Question 4

What is one type of typical antipsychotic and how can it be taken?

Answer 4

• (since 1950s) Chlorpromazine
• can be taken as tablets, syrup or by injection
• taken orally it is administered daily up to max of 1000mg
• initial does are smaller & for most people dosage is gradually increased to a max of 400-800mg

Question 5

How do typical antipsychotics like chlorpromazine work?

Answer 5

• strong association with the DA hypothesis
• they work by acting as antagonists (reduce action of neurotransmitters) in the dopamine system
• DA antagonists block dopamine receptors in the synapses of the brain which reduces the action of dopamine

Question 6

What are the effects of chlorpromazine on the dopamine system?

Answer 6

• when an individual begins taking chlorpromazine dopamine levels builds up, but then production is reduced
• this dopamine-antagonists effect normalises neurotransmission in key areas of the brain reducing symptoms like hallucinations

Question 7

What effect does chlorpromazine also have?

Answer 7

• sedation effect
• used to calm individuals not only with SZ but with other conditions
• used with patients first admitted to hospitals & are very anxious
• used in syrup form for sedative affect as it is absorbed faster

Question 8

What are the two atypical antipsychotic?

Answer 8

• Clozapine (300 to 450mg a day)
• Risperidone

Question 9

What were the main aims of the atypical antipsychotics?

Answer 9

• to improve effectiveness in suppressing symptoms and minimise side effects

Question 10

When was clozapine first used and why was it withdrawn?

Answer 10

• first trialled in the 1970s
• it was withdrawn following deaths of some patients from a blood condition called agranulocytosis
• 1980s it was discovered to be more effective than typical antipsychotics and used when other treatments failed (treatment resistant cases)

Question 11

If clozapine is used how do individuals ensure they are not developing agranulocytosis?

Answer 11

• regular blood tests

Question 12

How does Clozapine work and what are its benefits?

Answer 12

• binds to dopamine receptors in the same way as chlorpromazine does but also > acts on serotonin and glutamate receptors as well
• this helps improve mood & reduce depression & anxiety
• & may improve cognitive functioning
• this mood enhancing effects means it is sometimes prescribed when an individual is considered high risk of suicide > important as up to 50% of people with SZ attempt suicide as some point

Question 13

Why was Risperidone developed and how can it be taken?

Answer 13

• since 1990s
• developed to be as effective as clozapine but without serious side effects
• can be taken in from of tablets, syrup, or an injection that lasts around 2 weeks
• small does initially given & is built up to to a typical daily dose of 4-8mg & a maximum of 12 mg (more effective so less)

Question 14

How does Risperidone work?

Answer 14

• like clozapine, risperidone is believed to bind to dopamine & serotonin receptors
• it binds more strongly to dopamine receptors than clozapine & is therefore effective in much smaller doses than most antipsychotics
• reduces side effects

Question 15

What is a strength of antipsychotics?

Answer 15

• evidence to support their effectiveness
• Thornley et al> reviewed studies comparing the effects of chlorpromazine to control conditions
• data from 13 trials showed that chlorpromazine was associated with better overall functioning & reduced symptom severity as compared to placebo
• also evidence for the benefits of atypical antipsychotics > In Meltzer’s review he concluded that clozapine is more effective than typical antipsychotics & other atypical antipsychotic & that it is effective in up to 50% of treatment resistant cases were typical antipsychotics have failed
• implies that clinical evidence suggests that both typical & atypical antipsychotics are effective in treating symptoms of SZ

Question 16

What is a counterpoint to effectiveness of antipsychotics?

Answer 16

• Healy has suggests serious flaws in the evidence for effectiveness
• e.g. most studies are of short term effects only & some successful trials have had their data published multiple times exaggerating the size of evidence base for positive effects (publication bias)
• also because some antipsychotics have powerful calming effects it is easy to demonstrate that they have some positive effect on people experiencing the symptoms of SZ > not the same as saying that they actually reduce the severity of psychosis
• evidence base for effectiveness of antipsychotics is not as significant than it first appears

Question 17

What is a limitation of antipsychotics?

Answer 17

• the likelihood of side effects
• typical AP’s are associated with a range of side effects including, weight gain, dizziness, stiff jaw, sleepiness etc.
• long term use can result in tardive dyskinesia, which is caused by dopamine super sensitivity which causes involuntary facial movements such as grimacing, blinking & lip-smacking
• most serious side effect of antipsychotics (typical) is neuroleptic malignant syndrome (NMS)
• this is believed to be caused when the drug blocks dopamine action in the hypothalamus, an area in the brain associated with the regulation of a number of body systems > NMS results in high temperature, coma & can be fatal
• AP’S can do harm as well as good > means some may avoid treatment

Question 18

What is another limitation of antipsychotics?

Answer 18

• we do not know why they work
• understanding of how antipsychotic drugs work strongly links with the original dopamine hypothesis > the idea that symptoms of SZ are linked to high levels of dopamine activity in the subcortex of the brain
• this hypothesis is not complete and in the updated dopamine hypothesis, we now know that dopamine levels in other parts of the brain are too low rather than too high
• if this is true, the AP’s should not work so given that there are already questions over the effectiveness > this adds to the argument that they are ineffective
• means AP’S may not be the best treatment to opt for > other factor involved in apparent success