Biological therapies for schizophrenia: Drug therapy:

    Cards (10)

    • Typical antipsychotics:
      • Dopamine antagonists:
      Typical antipsychotic drugs (e.g. chlorpromazine) have been around since the 1950s. They work by acting as antagonists in the dopamine system & aim to reduce the action of dopamine - they are strongly associated with the dopamine hypothesis
    • Typical antipsychotics:
      • Block dopamine receptors in the synapses: 
      Dopamine antagonists work by blocking dopamine receptors in the synapses in the brain, reducing the action of dopamine. Initially, dopamine levels build up after taking chlorpromazine, but then production is reduced. This normalises neurotransmission in key areas of the brain, which in turn reduces symptoms like hallucinations.
    • Typical antipsychotics:
      • Chlorpromazine also has sedation effect:
      Chlorpromazine also has an effect on histamine receptors which appears to lead to a sedation effect. Therefore it is also used to calm anxious patients when they are first admitted to hospital
    • Atypical antipsychotics:
      • Target dopamine & serotonin:
      Atypical antipsychotics such as Clozapine have been used since the 1970s. The aim of these drugs was to impose effectiveness of drugs in suppressing psychoses such as schizophrenia & also minimise the side effects. They typically target a range of neurotransmitters including dopamine & serotonin 
    • Atypical antipsychotics:
      • Clozapine acts on dopamine, glutamate & serotonin to improve mood:
      Clozapine binds to dopamine receptors as chlorpromazine does but also acts on serotonin & glutamate receptors. This drug was more effective than typical antipsychotics - clozapine reduces depression & anxiety in patients as well as improving cognitive functioning. It also improves mood, which is important as up to 50% of people suffering from schizophrenia attempt suicide 
    • Atypical antipsychotics:
      • Risperidone is as effective as clozapine but safer:
      Risperidone was developed because clozapine was involved in the deaths of some patients from a blood condition called agranulocytosis. Risperidone like clozapine binds to dopamine & serotonin receptors. But risperidone binds more strongly to dopamine receptors & is therefore more effective in smaller doses than most antipsychotics & has fewer side effects
    • Strength is evidence shows antipsychotics are moderately effective:
      Thornley et al (2003) reviewed data from 13 trials & found that chlorpromazine was associated with better functioning & reduced symptom severity compared with placebo. There is also support for the benefits of atypical antipsychotics. Meltzer et al. (2012) concluded that clozapine is more effective than typical antipsychotics, & that it’s 30-50% more effective in treatment-resistant cases. Therefore the evidence suggests that antipsychotics are reasonably effective
    • Limitation of antipsychotic drugs is side effects:
      Typical antipsychotics are associated with dizziness, agitation, sleepiness, weight gain, etc. Long-term use can lead to  lip-smacking & grimacing due to dopamine supersensitivity. The most serious side effect is neuroleptic malignant syndrome (NMS) caused by blocking dopamine action in the hypothalamus (can be fatal). Atypical antipsychotics were developed to reduce side effects but some still exist & this is a serious limitation of antipsychotic drug therapies.
    • Limitation:
      Exaggerates the positive effects. Also, studies only review short-term effects. Healey also suggests that antipsychotics have powerful calming effects but it may not be effective in reducing psychosis.
    • Limitation is that antipsychotic drugs may simply be a ‘chemical cosh’:
      Antipsychotics may have been used in hospital situations to calm patients and make them easier to work with. Short-term use of antipsychotics to calm patients is recommended by the National Institute for Health & Care Excellence (NICE). However, this practice is seen as human rights’ abuse. This raises ethical issues in the use of antipsychotic drugs with schizphrenia patients
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