Biological Therapy for Schizophrenia

• Antipsychotics

  - drugs used to reduce the intensity of symptoms, particularly the positive ones, in psychotic conditions like schizophrenia
• Typical Antipsyhotics


  - first generation of drugs for schizophrenia (around since 1950s)

  
  

  - can be taken as a tablet, syrup or injection

  
  

  - if taken orally maximum daily dose is 1000mg

  
  

  - normalises the transmission in key areas of the brain reducing symptoms like hallucinations

  
  

  - e.g. chloropromazine
• Chloropromazine as a Dopamine Antagonist

  - works as a dopamine antagonist; blocks dopamine receptors in the synapses of the brain reducing the action of dopamine

  
  

  - when taking chloropromazine dopamine tends to build up, but then its production is reduced

  
  

  - this dopamine-antagonist effect normalises neurotransmission in key areas of the brain reducing symptoms such as hallucinations
• Chloropromazine: Sedation Effect

  - chloropromazine also an effective sedative

  
  

  - chloropromazine is often used to calm individuals not only with schizophrenia but also with other conditions

  
  

  - this is often done when patients are first admitted to hospitals and very anxious

  
  

  - syrup is absorbed faster than tablets so it tends to be given when chloropromazine is used as a sedative
• Atypical Antipsychotics

  - developed after typical antipsychotics, target a range of neurotransmitters (used since the 1970s)

  
  

  - main aim is to suppress symptoms of psychosis and also minimise the side effects of the drugs used
• Atypical Antipsychotic: Clozapine


  - developed in the 1960s and first trialled in the early 1970s

  
  

  - was withdrawn for a while due to some patients dying from agranulocytosis

  
  

  - was used to treat schizophrenia when it was discovered in the 1980s to be more effective than chloropromazine

  
  

  - individuals that use it have to get regular blood tests to ensure agranulocytosis doesn't occur

  
  

  - the risk of agranulocytosis is also they reason it is not taken as an injection
• How Clozapine Works

  - binds to dopamine the same way chloropromazine does but also serotonin and glutamate

  
  

  - this action helps reduce depression and anxiety in patients as well as improving mood and potentially improving cognitive function

  
  

  - this means that it is often given to patients with suicidal tendencies and ideations

  
  

  - this is important as 30-50% of people with schizophrenia attempt suicide at some point
• Atypical Antipsychotic: Risperidone


  - more recently developed antipsychotic (~ 1990s)

  
  

  - developed in an attempt to produce a drug as effective as clozapine but without its serious side effects

  
  

  - can be taken in the form of tablet, syrup or an injection

  
  

  - binds more strongly to dopamine receptors than clozapine and is therefore more effective in small doses

  (average daily dose is 4-8 mg, max dose 12 mg/day)
• Evidence for Effectiveness: Strength

  - (Thornley et al, 2003) reviewed studies comparing effects of chloropromazine to control conditions

  
  

  - data from 13 trials and 1121 participants showed chloropromazine was associated with better overall functioning and reduced symptom severity as compared to a placebo

  
  

  - (Meltzer, 2012) concluded clozapine is more effective than typical antipsychotics and other typical antipsychotics

  
  

  - it is effective in 30-50% of treatment-resistant cases where typical antipsychotics have failed
• Evidence for Effectiveness: Counterpoint


  - (Healy, 2012) suggested serious flaws with evidence for effectiveness

  
  

  - e.g. most studies are short-term effects only and some successful trials had their data published multiple times, exaggerating the size of evidence base for positive effects

  
  

  - antipsychotics also have powerful calming effects so it is easy to demonstrate a positive effect on people experiencing symptoms of schizophrenia

  
  

  - this isn't the same as reducing the severity of psychosis
• Various Side Effects: Limitation


  - typical antipsychotics are associated with a range of side effects including dizziness, agitation, sleepiness stiff jaw, weight gain and itchy skin

  
  

  - long-term use can lead to tardive dyskinesia (involuntary facial movements)

  
  

  - the most serious side-effect of antipsychotics is neuroleptic malignant syndrome (NMS) which results in high temperature, delirium, and coma

  
  

  - NMS can be fatal

  
  

  - this means that antipsychotics can do harm as well as good
• Mechanism Unclear: Limitation


  - it is not clear how antipsychotics work

  
  

  - the understanding of how antipsychotics work is closely tied to the original dopamine hypothesis (schizophrenia is linked to hyperdopaminergia in the subcortex of the brain)

  
  

  - the original hypothesis is not a complete alternative for schizophrenia (hypodopaminergia is also cited as cause for schizophrenia)

  
  

  - if this is true then antipsychotics shouldn't work; give that there are questions about the effectiveness of antipsychotics anyway this adds to the argument that they are ineffective
• The Chemical Cost


  - (Moncrieff, 2013) it has been argued in hospital situations to calm people with schizophrenia and make them easier for staff to manage rather than benefiting patients

  
  

  - it could also be argued that calming people experiencing hallucinations and delusions almost certainly makes them feel better

  
  

  - calming patients also allows them to engage with other treatments (e.g. cognitive behaviour therapy)