Biological therapy

• Antipsychotics= drugs used to reduce the intensity of symptoms of psychosis.

  Psychosis= experiences some loss of contact with reality. Eg: hallucinations or delusions.
• Typical antipsychotics

  = First generation of drugs for schizophrenia.

  • They work as dopamine antagonists and include chlorpromazine.
• Dopamine antagonists

  = Strong association between the use of typical antipsychotics like chlorpromazine and the dopamine hypothesis.
• Chlorpromazine

  • Typical antipsychotics work by acting as antagonists in the dopamine system.
  • Antagonists are chemicals which reduce the action of a neurotransmitter.
  • opamine antagonists work by blocking dopamine receptors in the synapses of the brain, reducing the action of dopamine.
  • Initially dopamine levels build up, but then its production is reduced. According to the dopamine hypothesis of schizophrenia this dopamine antagonists effect normalises neurotransmitters, reducing symptoms like hallucinations.
• Sedation effect

  = Chlorpromazine is also an effective sedatives. This is believed to be related to its effects on histamine receptors.

  Chlorpromazine is often used to calm individuals- often when patients are first admitted to hospitals and are very anxious.
• Atypical antipsychotics

  = Drugs for schizophrenia developed after typical antipsychotics.

  • Aimed to develop newer antipsychotics to improve effectiveness of drugs in suppressing the symptoms of psychosis and minimise the side effects of drugs.
  • Include clozapine and risperidone.
• Clozapine

  = More effective than typical antipsychotics but patients have to have regular blood tests to ensure they aren't developing agranulocytosis.

  • Clozapine binds to dopamine receptors and acts on serotonin and glutamate receptors. The action helps improve mood and reduced depression and anxiety.
  • The mood enhancing effects of clozapine means its given to patients considered at high risk of suicide. 30-50% of people with schizophrenia have attempted suicide.
• Risperidone

  = Developed in attempt to produce a drug as effective as clozapine without serious side effects.

  • Binds to dopamine and serotonin receptors, stronger than clozapine.
  • More effective in much smaller doses.
• Evaluation- evidence for effectiveness

  • Evidence to support the idea that both typical and atypical antipsychotics are at least moderately effective in tackling symptoms of schizophrenia.
  • Thornley reviewed studies comparing effects of chlorpromazine to controls and found that chlorpromazine was associated with better overall functioning and reduced symptoms severity.
  • Meltzer concluded that clozapine is more effective than other antipsychotics.
  • So antipsychotics do work.
• Evaluation- counterpoint

  • Healy suggested serious flaws with evidence of effectiveness
  • For example most studies are short term effects only and some successful trials have had their data published multiple times, exaggerating the size of evidence base for positive effects.
  • Also because antipsychotics have powerful calming effects its easy to demonstrate they have some positive effect on people experiencing symptoms of schizophrenia. This isn't the same as saying they really reduce severity of psychosis.  
• Evaluation- serious side effects

  • Typical antipsychotics are associated with side effects including dizziness, agitation, sleepiness, stiff jaw, weight gain.
  • Long term use can result in tardive dyskinesia which is caused by dopamine supersensitivity and causes involuntary facial movements.
  • The most serious is neuroleptic malignant syndrome (NMS)-caused when the drug blocks dopamine action in the hypothalamus, an area associated with the regulation of a number of body systems.
  • NMS results in high temperature, delirium, coma and can be fatal.
• Evaluation- mechanism unclear

  • Don't know why antipsychotics drugs work.
  • Our understanding is strongly linked with the original dopamine hypothesis- the idea that symptoms of schizophrenia are linked to high levels of dopamine activity in the subcortex of the brain.
  • How this isn't a complete explanation as we know that dopamine levels in other parts of the brain are too low not too high. So antipsychotics shouldn't work.
  • Means that at least some antipsychotics may not be the best treatment.