Biological therapies for Schizophrenia: Drug therapy


Typical antipsychotics

  • Chlorpromazine
    • Strong association between use of TAs and the dopamine hypothesis.
    • TAs work as antagonists in the dopamine system. (Reduce action of neurotransmitter)
    • Dopamine levels build up initially but then production is reduced.
    • Normalises neurotransmitters in key areas of the brain, reducing symptoms such as hallucinations.
    • Effective sedative (histamine receptors).
    • Calm patients with SZ and other conditions.
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Atypical antipsychotics

  • Clozapine
    • Withdrawn after deaths due to blood condition (agranulocytosis)
    • Remarketed when discovered to be more effectve than TAs.
    • Regular blood tests.
    • Binds to dopamine receptors.
    • Acts on serotonin and glutamate receptors.
    • Improve mood and reduce depression and anxiety.
    • May improve cognitive functioning.
    • Perscribed when there is high risk of suicide.
  • Risperidone
    • More recently developed AA
    • Attempt to produce drug as effective as Clozapine but without side effects
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Evidence for effectiveness

  • Thornley et al.
    • Reviewed studies comparing effects of Chlorpromazine to control conditions (placebo) 
    • Chlorpromazine associated with better overall functioning and reduced symptom severity.
    • Relapse rate lower.
  • Meltzer
    • Clozapine more effective than TAs and other AAs.
    • Effective in 30-50% of treatment-resistant cases where TAs have failed.
  • Results inconclusive for Risperidone.                                                                                             
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Serious side effects

  • Side effects range from mild to serious and even fatal.
  • TAs
    • Dizziness
    • Agitation
    • Sleepiness
    • Stiff jaw
    • Weight gain
    • Itchy skin
    • Long term use - tardive dyskinesia (involuntary facial movements)
    • Neuroleptic malignant syndrome
      • High temperature, delirium and coma
      • 0.1-just over 2%
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Use of antipsychotics depends on the dopamine hypo

  • Idea that high levels of dopamine activity in the subcortex of the brain.
  • Evidence to show that this is not a complete explanation.
  • Dopamine levels may in fact be too low.
  • If this is true then it's not clear how antipsychotics work.
  • Modern understanding suggests that they shouldn't work.
  • Undermined faith in APs
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Problems with evidence for effectiveness

  • Healy
    • Some successful trials have their data published multiple times.
    • Evidence exaggerated of positive effects.
    • Easy to demonstrate positive effects (sedative)
    • Short-term benefits 

The chemical cosh argument

  • APs have been used to calm patients in hospitals.
  • Benefits staff rather than patients.
  • Seen as a human rights abuse.
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