Biological Therapy for Schizophrenia

• What are antipsychotics used for?

  To reduce symptoms of psychotic disorders
• What are the two types of antipsychotics?

  • Typical Antipsychotics
  • Atypical Antipsychotics
• What generation of drugs are typical antipsychotics?

  First generation for schizophrenia
• How do typical antipsychotics work?

  They act as dopamine antagonists
• What do dopamine antagonists do?

  Block dopamine receptors in the brain
• What additional effect does chlorpromazine have?

  It acts as an effective sedative
• How is chlorpromazine believed to induce sedation?

  By affecting histamine receptors
• How is chlorpromazine typically administered for sedation?

  As a syrup for faster absorption
• What characterizes atypical antipsychotics?

  • Developed after typical antipsychotics
  • Target multiple neurotransmitters
  • Reduce both positive and negative symptoms
• What receptors does Clozapine bind to?

  Dopamine, serotonin, and glutamate receptors
• What benefits does Clozapine provide?

  Improves mood and reduces anxiety
• When might Clozapine be prescribed?

  When an individual is at high risk of suicide
• Why is Clozapine not available by injection?

  Due to potential fatal side effects
• What monitoring is required for patients on Clozapine?

  Regular blood tests for agranulocytosis
• How does Risperidone differ from Clozapine in receptor binding?

  It binds more strongly to dopamine receptors
• What evidence supports the effectiveness of antipsychotics?

  Thornley et al (2003) reviewed studies
• What did Thornley et al (2003) find about chlorpromazine?

  It improved overall functioning and reduced symptoms
• What counterpoint did Healy (2012) raise about antipsychotic effectiveness?

  Evidence is based on short-term studies
• What issue did Healy (2012) highlight regarding successful trials?

  Data may have been published multiple times
• What is a serious side effect of typical antipsychotics?

  Tardive dyskinesia from dopamine supersensitivity
• What is neuroleptic malignant syndrome?

  A serious side effect of antipsychotics
• What causes neuroleptic malignant syndrome?

  Blocking dopamine in the hypothalamus
• What are the symptoms of neuroleptic malignant syndrome?

  High temperatures and delirium
• What does the original dopamine hypothesis suggest?

  It links antipsychotic effectiveness to hyperdopaminergia
• Why is the original dopamine hypothesis considered reductionist?

  Dopamine levels are too low in some brain areas
• What implication does the reductionist view have on antipsychotics?

  Some may not be the best treatment option
• What might be involved in the apparent success of antipsychotics?

  Other factors beyond dopamine action
• What is a strength for Antipsychotics?

  Evidence for Effectiveness

  • There is a large body of evidence to support the idea that antipsychotics are effective in tackling the symptoms of schizophrenia
  • Thornley et al (2003) reviewed studies comparing the effects of chlorpromazine to control conditions, which showed that chlorpromazine was associated with better overall functioning and reduced symptom severity compared to the placebo
  • This means that, as far as we can tell, antipsychotics work
• What is a limitation for Antipsychotics?

  Ineffective

  • Healy (2012) suggested flaws with evidence for effectiveness, such as, most studies only show short-term effects and successful trials have had their data published multiple times, exaggerating the size of the evidence base for positive effects
  • Also, because antipsychotics have powerful calming effects, it is easy to demonstrate that they have some positive effect on people, while not reducing the severity of psychosis
  • This means that the evidence base for antipsychotic effectiveness is less impressive than it appears
• What is a limitation for Antipsychotics?

  Serious Side Effects

  • Typical antipsychotics are associated with a range of side effects, and long-term use can result in tardive dyskinesia, which is caused by dopamine supersensitivity
  • The most serious side effect of antipsychotics is neuroleptic malignant syndrome, which is believed to be caused when dopamine is blocked in the hypothalamus, which can be fatal
  • This means that antipsychotic drugs can do harm as well as good and individuals who experience these may avoid such treatments, making it ineffective
• What is a limitation for Antipsychotics?

  Mechanism Unclear

  • Our understanding of the mechanism by which antipsychotic drugs work is tied with the original dopamine hypothesis and hyperdopaminergia, however the original hypothesis is reductionist as dopamine levels in other parts of the brain are too low
  • Thus, most antipsychotics should not work, and this adds to the argument that antipsychotics are ineffective
  • This means that at least some of the antipsychotics may not be the best treatment to opt for, and perhaps some other factor is involved in their apparent success