schizophrenia- biological therapies

Question 1

what are antipsychotics

Answer 1

drugs used to reduce the intensity of symptoms, in particular the positive symptoms of psychotic conditions like schizophrenia

Question 2

what are typical antipsychotics

Answer 2

the first generation of antipsychotics drugs having been used since the 1950s.
they work as dopamine antagonists

Question 3

what is an example of a typical antipsychotics?

Answer 3

chlorpromazine

Question 4

describe properties of chlorpromazine

Answer 4

taken as tablets
taken orally
administered daily up to a maximum of 1000mg
typical prescribed doses have decreased over years

Question 5

what do typical antipsychotics act as like ?

Answer 5

antagonists (chemicals that reduce the action of a neurotransmitter) in the dopamine system.

Question 6

how do dopamine antagonists work in the dopamine system ?

Answer 6

block dopamine dopamine receptors in the synapses of the brain,
reducing the action of dopamine
normalising neurotransmission in key areas - reducing symptoms like hallucinations

Question 7

chlorpromazine is also an effective ——–

Answer 7

sedative

Question 8

how is chloropromazine an effective sedative

Answer 8

effect on histamine receptors
used to calm people down with conditions other than schizophrenia as well

Question 9

what are atypical antipsychotics ?

Answer 9

drugs for schizophrenia developed after typical antipsychotics.
typically target a range of neurotransmitters such as dopamine and serotonin

Question 10

what are examples of atypical antipsychotics

Answer 10

clozapine and risperidone

Question 11

what are the properties of clozapine ?

Answer 11

more effective than typical antipsychotics
side effect of agranulocytosis
300 to 400mg a day dose

Question 12

how does clozapine work ?

Answer 12

binds to dopamine receptors but also acts on serotonin and glutamate receptors.

helps improve mood and reduce depression

Question 13

why are the mood enhancing effects of clozapine important

Answer 13

prescribed to those high risk of suicide - 30% to 50% of people with schizophrenia attempt suicide at some point

Question 14

what are properties of risperidone

Answer 14

quite new
in form of tablets, syrup or injection
4-8mg

Question 15

how does risperidone work

Answer 15

binds more strongly to dopamine receptors than clozapine and therefore more effective in much smaller doses than most antipsychotics

Question 16

what is a strength for typical antipsychotics

(evidence to support)

Answer 16

thornley et al (2003)
reviewed studies comparing the effects of chlorpromazine to control conditions

13 trials - 1121 participants showed chlorpromazine associated with better overall functioning - reduced symptom severity

typical antipsychotics likely to provide benefit

Question 17

strength for atypical antipsychotics

Answer 17

support for benefit of atypical antipsychotics

meltzer (2012

clozapine more effective than typical antipsychotics

effective in 30%-50% of treatment resistant cases where typical antipsychotics have failed

• studies have compared the effectiveness of clozapine and other atypical AP → results inconclusive generally effective

Question 18

limitation of typical antipsychotics (side efects)

Answer 18

likelihood of side affects

associated with range of side effects

most serious → neuroleptic malignant syndrome

drug blocks dopamine action in the hypothalmus - area of brain associated regulation of body systems

NMS - high temp, delirium and coma + fatal

shows that typical antipsychotics can possibly lead to serious or fatal outcomes

Question 19

limitation + strength of atypical antipsychotics (side effects)

Answer 19

less side effects

ATp developed to reduce frequency of side effects and this has generally succeeded

however

clozapine - still have to take regular blood tests to detect agranulocytosis

side effects significant weakness of antipsychotic drugs

Question 20

what is another limitation of antipsychotics (problems with evidence)

Answer 20

vigorous challenges to usefullness of evidence

healy → succesful trials have had their data published many times, exaggerating the evidence for positive effects.

in addition many studies show short term benefits rather than long term.

this lowers the effectiveness of antipsychotics as it questions their validity