lesson 8 - drug therapy for schizophrenia Flashcards
what typical anti-psychotic drugs
- Common examples of these drugs include: Chlorpromazine, Phenothiazines and Thorazine,
- These drugs are available as a tablet, syrup or injection.
- Chlorpromazine is a popular typical anti-psychotic drug and acts as a sedative.
- Typical drugs are less popular than atypical drugs (see later on)
- Typical drugs aim to reduce the positive symptoms of schizophrenia such as delusions and hallucinations that have been caused by high dopamine levels.
- These drugs reduce dopamine levels in the brain and act as dopamine antagonists. These drugs block dopamine receptors at the synapse.
- The drugs bind to dopamine receptors (D2) in the mesolimbic dopamine pathway in the brain and reduce the positive symptoms of schizophrenia such as delusions and hallucinations.
- The drugs must bind to 60-75% of the D2 receptors and block their activity in order to be effective
strengths of typical anti-psychotic drugs
1) There is supporting evidence from Thornley (2003) that typical anti-psychotic drugs are effective in tackling symptoms of schizophrenia. He compared Chlorpromazine to a placebo and found that schizophrenia patients had better functioning and reduced severity of symptoms when they took Chlorpromazine compared to a placebo, and the relapse rate was lower. (+)
4) A strength of Typical anti-psychotic drugs is that they are effective in minimising symptoms of schizophrenia, they are cheap to produce and administer and help patients lead a relatively normal life outside of an institution. Around 97% of schizophrenia patients live at home, and this is because of the use of drug therapy (+)
5) Supporting research from Marder (1996) has found that typical anti-psychotic drugs are good at reducing the positive symptoms of schizophrenia such as delusions and hallucinations. However they do not have any effect on the negative symptoms of schizophrenia such as apathy and speech poverty. (+) (-)
weaknesses of typical anti psychotic drugs
2) A negative point about typical drugs is that they have terrible side effects which include dizziness, agitation, sleepiness, stiff jaw, weight gain, itchy skin and in the long term patients might develop, “tardive dyskinesia” (can be caused by dopamine super sensitivity) whereby mouth muscles and their chin make involuntary strange movement. (-)
3) A problem with typical anti-psychotic drugs has found that problems can occur when patients take the drug long term, for instance, 2% of schizophrenic patients’ develop the side effect of, “Neuroleptic malignant syndrome” which involves muscle rigidity, high temperature, delirium, altered consciousness, fever and a coma that can be fatal. (-)
5) Supporting research from Marder (1996) has found that typical anti-psychotic drugs are good at reducing the positive symptoms of schizophrenia such as delusions and hallucinations. However they do not have any effect on the negative symptoms of schizophrenia such as apathy and speech poverty. (+) (-)
6) A negative point about typical drugs is that they can produce terrible side effects called, “extra pyramidal side effects” whereby dysfunction occurs in the nerve tracts from the brain and the spinal motor neurons. The schizophrenia patient might develop side effects that resemble Parkinson’s disease such as tremors in the fingers, drooling and muscular rigidity. (-)
what are atypical anti-psychotic drugs
- There are alternative drugs available that seem to be better than neuroleptic drugs. Some examples of atypical anti psychotic drugs include Risperidone and Clozapine
- These drugs block the activity of dopamine receptors within the brain by acting on the D2 receptors (reduce dopamine). The drugs temporarily occupy the D2 receptors and then allow normal dopamine transmission.
- Atypical drugs also increase serotonin activity in the brain and bind to serotonin receptors (5-HT 2A) in order to improve mood
- These drugs have fewer side effects than typical drugs
- Atypical drugs also seem to be able to reduce both the positive and negative symptoms of schizophrenia, which is an improvement when comparing them to typical drugs
explain examples of atypical drugs
Clozapine: Atypical drug (AO1)
* It is given when there is a high risk that the schizophrenic patient might commit suicide
* Clozapine binds to dopamine receptor cells but also acts on serotonin and glutamate receptors too. This has the following effects on the schizophrenic patient:
* Improvement of mood
* Reduction of anxiety and depression
* Can improve cognitive functioning
Risperidone: Atypical drug (AO1)
* Risperidone is as effective as Clozapine but with less side effects
* Can be taken in tablet or syrup form
* Small doses are given to start with
* Risperidone binds more strongly to dopamine receptors than clozapine
strengths of atypical drugs
1) Typical and atypical drugs have their strengths in that they have been proven to be the most effective treatment when compared to any other form of therapy available for treating schizophrenia (biological or psychological) (+)
4) Meltzer (2012) conducted research to support the idea that Clozapine is a more effective drug for treating schizophrenia than typical anti-psychotic drugs and alternative drugs. Clozapine was found to be 30-50% more effective in minimising schizophrenia symptoms compared to typical drugs. (+)
weaknesses of atypical drugs
2) Drug therapy has the disadvantage that it treats the symptoms of schizophrenia, but not the cause of it. Symptoms might return if the patient stops taking the drugs and this leads to the, “Revolving door phenomenon” whereby patients leave hospital and then return because the drugs have failed to work (and this is a cycle). (-)
3) A problem with atypical drugs (and drugs in general), is that some schizophrenia patients are resistant to Clozapine and/or Risperidone as results from trials can sometimes be inconclusive about how effective they are. Some drugs will not be effective on some schizophrenic sufferers due to individual differences. (-)
5) A problem with drug therapy in general is that there are ethical issues that can be raised. Drugs have been referred to as being, “A chemical strait jacket” whereby they do not help the schizophrenic patient, but just aims to control them, sedate them and make them easier to manage. (-)
6) Atypical drugs such as Clozapine have serious side effects, one of them is called, “Agranulocytosis” which is a blood condition whereby the bone marrow is affected and less white blood cells are produced, which can affect immunity to illness. (-)
