Biological therapies for schizophrenia: Drug therapy

• Typical antipsychotics - Traditional drugs:

  • Act as antagonists in the dopamine system - Reduce action of a neurotransmitter
  • Block dopamine receptors in synapse of the brain - Reducing the action of dopamine + Normalises neurotransmission in key area of the brain e.g. hallucinations
  • E.g. Chlorpromazine
• Atypical antipsychotics - Second generation drugs - Clozapine:

  • Causes fatal blood condition
  • Used for when other treatments failed
  • Used today alongside regular blood tests
  • Daily dosage is low and no injections available
  • Binds to dopamine receptors + Acts on serotonin and glutamate receptors - Improve mood and reduce depression and anxiety
  • Prescribed for those who have a high risk of suicide - Mood-enhancing effects
• Atypical antipsychotics - Second generation drugs - Risperidone:

  • Taken through tablets, syrup or an injection that lasts two weeks
  • Small dose initially given and then built up
  • Binds to dopamine and serotonin receptor
  • Binds more strongly the Clozapine - Effective in small doses + May lead to fewer side effects
• Evaluation of drug therapies - Serious side effects:

  • Range from mild to fatal e.g. agitation and dizziness
  • Long term usage - Tardive dyskinesia - Caused by dopamine super sensitivity with involuntary movements
  • Neuroleptic malignant syndrome - Drugs blocking dopamine action in the hypothalamus - High temperature, delirium and can be fatal
  • Clozapine - Regular blood tests
• Evaluation of drug therapies - Use of antipsychotics depends on the dopamine hypothesis:

  • Drug usage - Based on the idea that there are higher than usual levels of dopamine activity in the subcortex of the brain
  • HOWEVER DH not a complete explanation for S - Dopamine levels are too low rather than too high
  • If true - Not clear how antipsychotics (Dopamine antagonists) help reduce dopamine activity

  Limitation: Undermine the fact that antipsychotics do work
• Evaluation of drug therapies - Problems with evidence for effectiveness

  Healy:

  • Suggested successful trials had multiple publishing times - Exaggerating evidence of positive effects
  • Antipsychotic have powerful calming effects - Easy to demonstrate positive effect - Not same as say reducing the severity of psychosis
  • Only assess short term benefits

  Limitation: Evidence of effectiveness is unreliable