Biological Explanaitions: Drug Therapy Flashcards
What are antipsychotic drugs?
Antipsychotics are drugs used to reduce the intensity of symptoms and are the most common treatment for schizophrenia.
What do antipsychotics involve?
They involve modifying the action of neurotransmitters in order to increase (agonists) or decrease (antagonists) their activity.
How is this medication taken?
Medication can be taken as pills, syrups or injections and may be taken over a short term or long term period.
What are the two categories antipsychotics can be divided into?
Typical (traditional) and atypical (second generation drugs)
What is a typical antipsychotic?
Developed in 1950s, for example chlorpromazine.
There is a strong association between the use of chlorpromazine and the dopamine hypothesis.
Typical antipsychotics act as dopamine antagonists , attempting to reduce dopamine activity
What are dopamine antagonists?
They work by blocking dopamine receptors in the synapses of the brain reducing the activity of dopamine.
What affect does reducing dopamine produce have on the symptoms of schizophrenia?
Reduces positive symptoms such as hallucinations.
What side affects do typical antipsychotics such as chlorpromazine have on the patient?
Have a sedative affect - meaning they calm the patients down and reduce anxiety.
As these drugs block dopamine activity they tend to have some severe side effects.
What are atypical antipsychotics?
Developed in the 1970s as an attempt to find drugs with fewer side effects than typical antipsychotics.
For example clozapine and risperidone.
What is clozapine ?
Acts in a similar way to chlorpromazine but also acts on serotonin and glutamate receptors.
As well as reducing positive symptoms, it aims to reduce depression and anxiety and enhances mood.
This drug is only used when others have failed due to severe side effects such as a risk of potentially fatal blood condition.
What is risperidone?
Designed to be as affective as clozapine without the severe side effects.
It binds to dopamine receptors more strongly than clozapine and there is some evidence that it produces fewer side effects.
Evaluate antipsychotics in terms of support: antipsychotics vs placebos.
Support for the effectiveness of antipsychotics comes from studies that have compared relapse rates for antipsychotics against placebos
Research by leucht et al - meta - analysis of 65 studies involving nearly 6,000 patients.
Some patients were taken off antipsychotics and given a placebo instead whilst other patients remained on antipsychotics
Within 12 months 64% of those on placebo drug relapsed compared to 27% of those who stayed on antipsychotics.
This demonstrates the effectiveness of antipsychotics in preventing relapse.
However it has been argued that many of these studies look at short term effects only.
In some cases of successful drug trials the data is published many times which gives an exaggerated effect of their success.
What is a limitation of antipsychotics in terms of serious side effects?
Support for the effectiveness of antipsychotics is weakened by extrapyramidal effects.
Long term use of antipsychotics can result in some patients developing tardive dyskinesia which is caused by dopamine super sensitivity and causes involuntary facial movements such as grimacing.
Even after stopping the drugs this condition can persist.
Other side effects are potential fatal such as neuroleptic malignant syndrome (nms) which is believed to be caused when the drug blocks dopamine action in the hypothalamus.
Nms can result in delirium and comas.
This is a limitation as patients will become reluctant to take the drugs or may even die as a result of these fatal side effects.
This suggests that antipsychotics can do harm to patients as well as good.
