AO1 - Drug Therapy Schizophrenia

• People with schizophrenia are usually offered antipsychotic medication to help reduce their positive symptoms.
• Antipsychotic drugs may be required in the short-term or the long-term. Some patients may require antipsychotic medication for life.
• Many antipsychotic drugs are used as the first form of treatment for patients with schizophrenia.
• Atypical antipsychotics, such as risperidone, are newer medications that also target negative symptoms of schizophrenia, such as social withdrawal and lack of motivation.
• Typical antipsychotics, such as chlorpromazine, primarily target positive symptoms of schizophrenia, such as hallucinations and delusions.
• Antipsychotic drugs fall into two types; typical drugs (first generation) which were developed in the 1950s and atypical drugs (second generation) which are newer and developed around the 1990s.
• Typical antipsychotics can be taken as tablets, syrup or by injection.
• Typical antipsychotic drugs work by blocking D2 receptors in parts of the limbic system in the brain.
• Many typical antipsychotics are known as dopamine antagonists. Antagonists are chemicals which reduce the action of neurotransmitter at the synapse.
• Dopamine antagonists work by blocking dopamine receptors in the synapses of the brain, reducing the action of dopamine.
• Typical antipsychotic drugs block dopamine receptors and reduce levels of excitation via dopamine at the synapse.
• Examples of typical antipsychotic drugs include Chlorpromazine, Fluphenazine and Haloperidol.
• Typical antipsychotics work to reduce the levels of hallucinations and delusions but tend not to be effective on the negative symptoms of schizophrenia.
• Many typical antipsychotics also act as a sedative and can help calm patients and reduce their anxiety.
• Atypical antipsychotics were developed to improve upon the effectiveness of drug therapy in suppressing the symptoms of psychosis but also to minimise the side effects.
• Atypical antipsychotic drugs are targeted and act on specific dopamine receptor sites, usually D2 receptors.
• Atypical antipsychotics work on both positive and negative symptoms of schizophrenia.
• Examples of atypical antipsychotic drugs are Clozapine, Quetiapine and Olanzapine.
• Clozapine binds to dopamine receptors but also acts on serotonin and glutamate receptors. It is believed that this action improves mood and helps to reduce anxiety and depression in patients.
• Meltzer (2012) concluded that clozapine is more effective than typical antipsychotics and other atypical antipsychotics.
• Risperidone is a more recently developed atypical antipsychotic and can be taken as a tablet, syrup or injection lasting up to two weeks.
• Risperidone is believed to bind to dopamine and serotonin receptors, and results in fewer side effects than other antipsychotics.
• Chlorpromazine is a typical antipsychotic which is often used to help calm individuals down, as it has a sedative effect.
• Thornley et al (2003) reviewed studies comparing the effects of chlorpromazine with a placebo. Data from 13 trials with a total of 1121 participants showed that chlorpromazine was associated with better overall functioning and reduced symptom severity.
• Comer et al (2001) claim that typical antipsychotic drugs reduce schizophrenic symptoms in the majority of patients but are less successful at treating negative symptoms such as flattened affect.
• Typical antipsychotics have more side effects such as dry mouth, blocked nose, urinary problems and in some case tardive dyskinesia (facial twitching).
• Atypical antipsychotics have less side effects but patients can still be at risk of weight loss and sleep disruption.
• Smith et al (2010) suggest that antipsychotic drugs can reduce the positive symptoms of psychosis in 8-15 days.
• Smith et al (2010) suggest that antipsychotic drugs often fail to significantly improve the negative symptoms and cognitive dysfunction associated with schizophrenia.
• Drug therapy is individualised and is based on benefits, risks and costs for each specific patient.
• Both typical and atypical antipsychotics have similar dropout rates and symptom relapse rates when used at low to moderate dosages.
• Clozapine is an effective treatment for patients who respond poorly to other drugs, but there is a higher risk of a serious side effect called agranulocytosis (reduced white blood cells).