biological therapies Flashcards
What is the main drug therapy?
Antipsychotics, available as tablets syrup or injections
Short or long term
Reduce intensity of symptoms
What are the types of antipsychotics?
Typical
Atypical
What is a type of typical antipsychotic?
Chlorpromazine
Administered daily
How do typical antipsychotics work?
Antagonists in dopamine system, reduce actions of NT
Block dopamine receptors in synapses
Dopamine initially builds up then production is reduced
Normalises neurotransmission in key areas, reducing hallucinations
How is Chlorpromazine also a sedative?
Related to effect on histamine receptors
Used to calm patients when they’re first admitted
Syrup works faster so this is used for sedative properties
Why were atypical antipsychotics developed?
Improve upon effectiveness of drugs but minimise side effects
What are some atypical antipsychotics?
Clozapine
Risperidone
Why was Clozapine initially withdrawn for a while and why did it return?
Deaths of patients from blood condition called agranulocytosis
Discovered to be more effective than typicals
People take regular blood tests to check for condition
Not available as injection due to side effects
How does Clozapine work?
Binds to dopamine receptors like Chlorpromazine
Acts on glutamate and serotonin receptors
Helps improve mood and reduce depression, improves cognitive functioning
Prescribed when patient at risk of suicide
What is Risperidone?
Developed to have less side effects
Small dose but built up
How does Risperidone work?
Binds more strongly to dopamine receptors than Clozapine
Effective in smaller doses, leading to fewer side effects
Evaluation - evidence for effectiveness
Thornley - compared Chlorpromazine to placebo
C associated with better functioning and reduced symptom severity, relapse rate lower
Meltzer - Clozapine more effective than typicals, effective in 30-50% cases where typicals have failed
Evaluation - side effects
Typicals associated with tardive dyskinesia (involuntary facial movements) as well as agitation and stiff jaw
Typicals = neuroleptic malignant syndrome - blocks dopamine action in hypothalamus, resulting in delirium and coma, can be fatal
Evaluation - use of antipsychotics depends on dopamine hypothesis
Evidence to show dopamine hypothesis isn’t complete - levels are too low not too high
How do dopamine antagonists work?
Undermines faith in drugs
Evaluation - problems with evidence for effectiveness
Healy - some successful trials have been published multiple times to exaggerate success
Calming effects means it’s easy to show positive effects, but not the same as reducing psychosis
