AO1

• Typical antipsychotics, e.g. chlorpromazine, have been around since the 1950s. They act as antagonists in dopamine and aim to reduce action of dopamine.
• Dopamine antagonists block dopamine receptors in the synapses in the brain, reducing the action of dopamine. Initially, dopamine levels build up after taking clopramazine, but then production is reduced. This normalises neurotransmission in key areas of the brain, which in turn reduces symptoms like hallucinations.
• Chlorpromazine also has an effect on histamine receptors, which appears to lead to a sedation effect. This is generally used to calm anxious patients when they are first admitted to hospital.
• The aim of developing newer antipsychotics was to maintain or improve on the effectiveness of drugs in suppressing the symptoms of psychosis and also to minimise the side effects of the drugs used.
• Clozapine binds to dopamine receptors too, but also acts on serotonin and glutamate receptors. Clozapine is more effective than typical antipsychotics because it reduces depression and anxiety as well as improving cognitive functioning.
• Risperidone was developed in the 1990s because clozapine was involved in the deaths of some people from a blood condition called agranulocytosis Risperidone binds to dopamine and serotonin receptors. It binds more strongly to dopamine receptors and is therefore more effective in smaller doses than most antipsychotics and has fewer side effects.