Biological therapy for schizophrenia

Question 1

strengths of antipsychotics

Answer 1

1. evidence for effectiveness
   - support the idea that typical and atypical antipsychotics are moderately effective in tackling the symptoms to schizophrenia
   - thorpley et al (2003) reviewed studies comparing the effects of chlorpromazine to control conditions
   - data form 13 trials with 1121 participants showed that chlorpromazine was associated with better overall functioning and reduced symptom severity compared to placebo
   -review by Meltzer (2012) concluded that clozapine is more effective than typical and atypical antipsychotics
   - effective in 30-50% of treatment resistant cases where typical antipsychotics have failed

Question 2

limitations of antipsychotic drugs

Answer 2

1. serious side effects
   - dizziness, agitation, sleepiness, weight gain and itchy skin
   - long term use can result in tardive dyskinesia which is caused by dopamine supersensitivity and causes involuntary facial movements such as grimacing and lip smacking
   - most serious side effect is neuroleptic malignant syndrome (NMS), caused when the drug blocks dopamine action in the hypothalamus (regulation of body system) and results in high temperature delirium and coma or fatal
   - may lead to avoidance of treatment so economic implication
2. mechanism unclear
   - we do not know why they work
   - understanding is tied up with the original dopamine hypothesis ()symptoms are linked to high levels of dopamine in the subcortex of the brain)
   - however we now know that low levels of dopamine in other parts of the brain are also involved
   - so most psychotic drugs should not work
   - adds to the argument that they are ineffective.

Question 3

typical antipsychotics

Answer 3

• since the 1950s
• chlorpromazine
• taken as a tablet, syrup or injected
• maximum dose of 1000mg if taken orally
• prescribed dosage has declined over the last 50 years

Question 4

dopamine antagonist

Answer 4

• strong association between the use of typical antipsychotics and the dopamine hypothesis
• work by acting as an antagonist in the dopamine system
• dopamine antagonists work by blocking dopamine receptors in the synapse of the brain reducing the action of dopamine
• initially when individuals start taking chlorpromazine dopamine levels build up but then production is reduced
• reduces symptoms like hallucination

Question 5

sedation effect

Answer 5

• chlopromazine is an effective sedative
• lined to its effect on histamine receptors but is not fully understood how this leads to sedation
• chlorpromazine is used to calm individuals with schizophrenia and other conditions
• done when patients are first admitted to hospitals and are anxious

Question 6

atypical antipsychotics

Answer 6

• used since the 1970s
• aimed to improve the effectiveness of drugs in suppression the symptoms of psychosis and minimise the side effects
• clozapine and risperidone

Question 7

clozapine

Answer 7

• developed in the 1960s and trialled in the 1970s
• withdrew in the 1970s following the death of patients form agranulocytosis
• 1980s discovered to be more effective than typical antipsychotics
• remarketed as a treatment for schizophrenia when other treatments failed
• used today and people take regular blood tests to make sure that they are not developing agranulocytosis
• dosage of 300 - 450 mg a day
• binds to dopamine receptors but also acts on serotonin and glutamate receptors
• improves mode and reduces depression and anxiety in patients
• improves cognitive functioning
• prescribed when patient at high risk of suicide (30 - 50% of schizophrenics attempt suicide)

Question 8

risperidone

Answer 8

• since the 1990s
• attempt to produce a drug as effective as clozapine without the serous side effects
• can be taken as tablets, injection or syrup
• maximum dose of 12mg
• binds to dopamine and serotonin receptors
• binds stronger to dopamine receptors than clozapine so is more effective in smaller doses