Biological therapy Flashcards
What are anti-psychotics?
- Drugs used to reduce intensity of symptoms (particularly positive symptoms)
What are the 2 types of antipsychotics?
- Typical
- Atypical
When were typical antipsychotics developed?
- 1950s
What are some examples of typical antipsychotics?
- Chlorpromazine
- Haloperidol
What is the usual dosage for typical antipsychotics?
- Orally taken- 400-800 mg daily
- Max 100 mg
How are typical antipsychotics taken?
- Tablets
- Syrup
- Injection
How do typical antipsychotics work as dopamine antagonists?
- Block dopamine receptors in brains synapses
- Reduce dopamine action
- Initially, chlorpromazine causes DA levels to increase, before stopping its production
- Normalises neutransmission in brain- reduces symptoms, i.e. hallucinations
How do typical antipsychotics have a sedative effect?
- Related to its effect on histamine receptors
- Used to calm individuals
- Syrup absorbed faster so used for sedative effects
What are typical antipsychotics?
- Dopamine antagonsists used to treat schizophrenia
What are atypical antagonists?
- Drugs that target a range of neurotransmitters, used to treat schizophrenia
When were atypical antipsychotics developed?
- 1970s
Why were atypical antipsychotics developed?
- To maintain/improve effectiveness of drugs in suppressing psychosis
- To minimise side effects of typical antipsychotics
What are some examples of atypical antipsychotics?
- Clozapine
- Risperidone
What is the usual dosage of atypical antipsychotics?
- Clozapine= 300-450 mg daily
- Risperidone= 4-8 mg daily, 12 mg max
What is a major issue with clozapine?
- Associated with angranulocytosis (blood condition)
- To be used when other treatments fail, due to high risk
- Patients receive blood tests to ensure they do not develop angranulocytosis
- Not available as injection
How are atypical antipsychotics taken?
- Clozapine= tablets, syrup
- Risperidone= tablets, syrup, injection
What is another use of clozapine?
- Suicide prevention
- Provided when individuals are at high risk (30-50% of schizophrenia patients attempt suicide)
How to atypical antipsychotics work?
- Clozapine= bind to dopamine receptors, act on serotonin and glutamate receptors- improve mood and cognitive functioning, reduces depression and anxiety
- Risperidone= Binds to dopamine and serotonin receptors (stronger than clozapine)
Strength-
I- Evidence for effectiveness
D- Thornley reviewed studies comparing chlorpromazine effects to controls. 13 trials, 1121 participants= showed chlorpromazine was associated with better overall functioning/reduced symptom severity. Meltzer concluded that clozapine is more effective than typical antipsychotics, and is effective in 30-50% of treatment- resistant cases
E- Means antipsychotics work to reduce schizophrenia
Limitation-
I- Flawed evidence
D- Healy suggests serious flaws with evidence for effectiveness. Most studies are short term only, some successful trials have had data published multiple times, exaggerates size of evidence base for positive effects. As antipsychotics have sedative effects, it is easy to demonstrate that they have a positive effect on patients
E- Means the evidence base is less impressive than it appears
Limitation-
I- Serious side effects
D- Typical antipsychotics associated with: dizziness, agitation, sleepiness, stiff jaw, weight gain, itchy skin. Long term use may result in tardive dyskinesia causing involuntary facial movement. Most serious effect= neuroleptic malignant syndrome (NMS)- caused when drug blocks DA action in hypothalamus- causes high temperature, delirium, coma (frequency= 0.1%-2%)
E- Means antipsychotics can do harm, leading to many people avoiding such treatments
Limitation-
I- The mechanisms of antipsychotics are unclear
D- Our understanding of how antipsychotics work is tied up with the original dopmaine hypothesis, which is an incomplete explanation- as DA levels in other parts of the brain are too low, not too high. If this were true, most antipsychotics would not work
E- Means that antipsychotics may not ve the best treatment to opt for
Evaluation extra-
I- The chemical cosh
D- Antipsychotics used in hospital situations to calm patients and make them easier to work with, rather to to benefit the individual. Temptations to use chlorpromazine to make patients more docile. But, claming distressed people does largely make them better, allowing them to better engage in further treatments (CBT) and services (meet a social worker to organise employment)
E- There are clear benefits to using antipsychotics to calm patients, so should be prescribed
