AO1

• the term ‘antipsychotic’ refers to psychosis, a person with psychosis experiences some loss of contact with reality
• typical antipsychotics include chlorpromazine which can be taken as tablets, syrup or injected
• if taken orally chlorpromazine is administered daily up to a maximum of 1000 mg, although doses are much smaller and for most the dosage is gradually increased up to 400 to 800 mg
• there is a strong association between the use of typical antipsychotics and the dopamine hypothesis
• typical antipsychotic drugs like chlorpromazine work by acting as antagonists in the dopamine system
• antagonists are chemicals which reduce the actions of a neurotransmitter
• dopamine antagonists work by blocking dopamine receptors in the synapses of the brain, reducing the action of dopamine
• initially when someone begins taking chlorpromazine dopamine levels build up but then its production is reduced
• according to the dopamine hypothesis this dopamine antagonist effect normalises neurotransmission in key areas of the brain, reducing symptoms like delusions
• chlorpromazine is also an effective sedative
• the sedative effect is believed to be related to its effect on histamine receptors
• chlorpromazine is often used to calm individuals with other conditions as well
• the aim in developing atypical antipsychotics was to maintain or improve upon the effectiveness of drugs in suppressing the symptoms of psychosis and also minimise the side effects
• Clozapine was remarketed as a treatment for schizophrenia after being discovered as more effective than typical antipsychotics
• because of its potentially fatal side effects clozapine is not available as an injection. Dosage is a littler lower than for chlorpromazine
• clozapine binds to dopamine receptors but in addition it acts on serotonin and glutamate receptors
• it is believed that this action helps improve mood and reduce depression and anxiety in patients and that it may improve cognitive functioning
• The mood enhancing effects of clozapine means that it is sometimes prescribed when someone is considered at high risk of suicide
• Risperidone was developed in an attempt to produce a drug as effective as clozapine but without its serious side effects
• risperidone can be take in the form of tablets, syrup or an injection that lasts for around two weeks
• for risperidone a small dose is initially given and this is built up to a typical daily dose of 4-8mg and a maximum of 12mg
• risperidon is believed to bind to dopamine and serotonin receptors
• risperidone binds more strongly than clozapine and is therefore effective in much smaller doses