Biological therapies for schizophrenia

• Drug therapies


  Most common treatment for schizophrenia involves the use of antipsychotic drugs
• Taking antipsychotic drugs

  1. Taken as tablets or syrup

  2. For those at risk, taken as injection every 2-4 weeks
• Duration of antipsychotic drug use

  • Required in short or long term
  • Short term - use until symptoms don't return
  • Long term - face likelihood of a recurrence of schizophrenia
• Types of antipsychotics

  • Typical antipsychotics
  • Atypical antipsychotics
• Typical antipsychotics

  • First generation antipsychotics
  • Used since 1950s
  • Chlorpromazine
• Chlorpromazine

  • Can be taken as tablet, syrup or injection
  • Daily maximum - 100mg
  • Initial dosages smaller - gradual increase to 400-600mg
• Use of chlorpromazine has declined in the last 50 years (Liu and de Haan, 2009)
• Dopamine antagonists


  • Chemicals which reduce the action of a neurotransmitter
  • Work by blocking dopamine receptors in the synapses of the brain - reducing action of dopamine
• When patients first start taking chlorpromazine


  Dopamine levels build up and then production is reduced
• Effect of dopamine antagonists


  Normalises neurotransmission in key areas of the brain - reducing symptoms like hallucination
• Sedation effects of chlorpromazine


  • Act as an effective sedative
  • Believed to be related to effect on histamine receptors
  • Calm people with schizophrenia and other conditions
• Chlorpromazine may be used to make schizophrenic patients tamer and controlled due to the stigma surrounding schizophrenia in the 1950s
• Atypical antipsychotics


  • Used since 1970s
  • Development was due to a desire to maintain and improve upon the use of drugs in suppressing symptoms of psychosis and minimise side effects
• Clozapine

  • Developed in 1960s
  • Withdrawn in 1970s following the death of some patients from a blood condition called agranulocytosis
  • Rediscovered to be effective against schizophrenia in the 1980s
  • Remarketed as a typical antipsychotic and to be used against schizophrenia when other treatments have failed
  • Still used but patients are required to take regular blood test to ensure they haven't developed agranulocytosis
  • Cannot be taken as an injection due to its potentially fatal side effects
  • Binds to dopamine receptors but also serotonin or glutamine receptors
  • Helps improve mood, depression and reduce negative thought of suicide
• Risperidone


  • Around since 1990s
  • Produced with the aim to be as effective as clozapine without the fatal side effects
  • Taken in the form of tablet, injections or syrup
  • Small dosage - typical daily dose of 4-8mg and maximum 12mg
  • Binds to both dopamine and serotonin receptors
  • More strongly binds to dopamine receptors than clozapine and is effective in much smaller doses
  • Fewer side effects than any other antipsychotics
• 30% -50% of people with schizophrenia attempt suicide at one point
• Mechanism is unclear - 🙁  

  • It is unclear how many antipsychotics work  
  • Our understanding is intertwined with the original dopamine hypothesis - the idea that there are high levels of dopamine activity in the sub-cortex of the brain - Hyperdopaminergia 
  • But this idea has already been refuted by psychologists who now claim that low levels of dopamine in other parts of the brain are too low rather than too high.  
  • If these new theories were correct then most antipsychotics should not work  
  • This further add to questions to the effectiveness of antipsychotics in really treating schizophrenia  
• Serious side effects - 1

  • Major problem with the use of antipsychotics is the likelihood of side effects  
  • These can range from serious to fatal  
  • Typical antipsychotics associated with symptoms like dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin  
  • Long term effects include development of tardive dyskinesia caused by dopamine supersensitvity and involutory facial movement such as blinking, lip smacking and grimacing  
• Serious side effects - 2

  • Most serious side effect neuroleptic malignant syndrome (NSM). Believed to be caused when typical side antipsychotics block dopamine action in the hypothalamus (regulates body systems)  
  • Can produce comas and high body temp - fatal  
  • Frequency of occurrence in patients is around 0.1-2%  
  • Means antipsychotics may do more harm than good. 
• However, Healy (2012), has suggested there are serious flaws with evidence for effectiveness.  

  • Most studies only look at short term effects  
  • Most successive trails have had their data published multiple times exaggerating the size of evidence for their positive effects  
  • Also, because antipsychotics are associated with calming effects it's easy to conclude that they are having positive effects on people with schizophrenia  
  • Not the sane as saying they reduce the severity of their psychosis