Schizophrenia - Biological Therapies Flashcards
What are antipsychotics?
Antipsychotics – Drugs used to reduce the intensity of symptoms, in particular the positive symptoms, of psychotic conditions like schizophrenia.
What are typical antipsychotics?
Typical antipsychotics – The first generation of antipsychotic drugs, having been used since the 1950s. They work as dopamine antagonists and include Chlorpromazine.
What are atypical antipsychotics?
Atypical antipsychotics – Drugs for schizophrenia (a psychotic disorder) developed after typical antipsychotics. They typically target a range of neurotransmitters such as dopamine and serotonin. Examples include Clozapine and Risperidone.
How do typical antipsychotics work?
Typical antipsychotics, such as Chlorpromazine, work as dopamine antagonists. They block dopamine receptors in the synapses of the brain, reducing the action of dopamine. This normalises neurotransmission in key areas of the brain, reducing symptoms like hallucinations. Chlorpromazine can also act as a sedative, calming patients with schizophrenia or other conditions.
What is the dopamine hypothesis’ link to typical antipsychotics?
Typical antipsychotics like Chlorpromazine support the dopamine hypothesis by reducing dopamine activity. However, this reduction can also lead to side effects and sedation, as they affect several neurotransmitter systems in the brain.
How do atypical antipsychotics like Clozapine work?
Clozapine binds to dopamine receptors like typical antipsychotics but also acts on serotonin and glutamate receptors. This helps improve mood and reduce depression and anxiety, which is important as 30-50% of people with schizophrenia attempt suicide. Clozapine is taken daily at doses starting at 300 mg and up to 450 mg a day.
How does Risperidone differ from Clozapine?
Risperidone binds to dopamine and serotonin receptors more strongly than Clozapine, meaning smaller doses (typically 4-8 mg daily, maximum 12 mg) are effective. This may lead to fewer side effects compared to other antipsychotics.
What is one evaluation point about the effectiveness of antipsychotics?
Evidence from Ben Thornley et al. (2003) shows that Chlorpromazine is more effective than a placebo, as patients treated with it had better overall functioning and reduced symptom severity. Studies also found Clozapine to be effective in 30-50% of treatment-resistant cases, although effectiveness is sometimes exaggerated in published research.
What is one evaluation point about side effects of antipsychotics?
Antipsychotics, especially typical ones, can cause severe side effects such as dizziness, agitation, weight gain, and even neuroleptic malignant syndrome (NMS), which affects 0.1%-2% of patients. NMS is caused by dopamine blockage in the hypothalamus, leading to high temperatures and coma.
What is one evaluation point about the dopamine hypothesis and antipsychotics?
Some evidence challenges the dopamine hypothesis, as antipsychotics reduce dopamine activity, yet studies show parts of the brain may have lower dopamine levels in schizophrenia, contradicting this theory.
What is one evaluation point about problems with evidence for effectiveness?
David Healy (2012) argues that published success rates for antipsychotics may exaggerate effectiveness. Studies with positive outcomes are often repeated, while negative results are less likely to be published. This highlights the issue of publication bias in evaluating treatments.
