Biological therapies

• How do we treat schizophrenia?

  Drugs in the form of tablets or medicine and can be taken long term or short term. 

  Antipsychotic drugs – Typical (traditional) & Atypical (newer)

  It is thought that schizophrenics produce too much dopamine or have more dopamine receptors than non-schizophrenics. We cannot decrease the amount of dopamine or reduce the number of receptors so the next best thing is to block the receptors. This is what Typical Antipsychotics do.
• Typical antipsychotics

  This acts in a very similar way as antidepressants. 

  SSRIs block the reuptake of serotonin to increase the presence of the NRT in the synapse, antipsychotics simply block the receptors on the postsynaptic neuron instead
• Typical antipsychotics

  = chlorpromazine

   -dopamine antagonists

  Bind to dopamine receptors without stimulating them, blocking the action of dopamine.

  Hallucinations and delusions diminish within a few days

  60-75% of D2 dopamine receptors in the mesolimbic pathway must be blocked to be effective.

  However other D2 receptors in other brain areas are also blocked causing harmful side effects.
• Atypical antipsychotics

  = clozapine

  Only temporarily occupy the D2 receptors, then rapidly dissociate to allow dopamine transmission. This avoids side effects.

  Also occupy serotonin receptors and are claimed to benefit the negative and cognitive symptoms of Sz as well as positive symptoms.
• AO3 - Drug therapy

  (+) effectiveness: antipsychotics versus placebo

  Meta-analysis of 65 studies including 6000 patients concluded that 64% patients taken off antipsychotics and given a placebo relapsed within 12 months compared to 27% of those who stayed on antipsychotics.

  = this shows effectiveness of antipsychotic treatment.

  Ethical issues?
• AO3 - Drug therapy

  (-) Ethical issues. Long term use of antipsychotics can result in:

  Tardive Dyskinesia – a syndrome in which the patient experiences involuntary movements of the face and body. 

  Agranulocytosis - a deficiency of granulocytes in the blood, causing increased vulnerability to infection

  Neuroleptic malignant syndrome (NMS) -  a life-threatening idiosyncratic reaction to antipsychotic drugs characterized by fever, altered mental status, muscle rigidity, and autonomic dysfunction.
• AO3 - Drug therapy

  (-) extrapyramidal side effects

  Typical antipsychotics produce movement problems such as Parkinsonism in 50% of patients. They affect the extra pyramidal area of the brain which helps control motor function. 

  After an extended treatment period, tardive dyskinesia can also occur (= involuntary movement of tongue, face and jaws).

  Those distressing symptoms cause many patients to stop taking their medication, and also raise ethical issues in prescribing these drugs.
• AO3 - Drug therapy

  (+) Are atypical antipsychotics better?

  Meta-analysis of 15 studies found no significant difference between typical and atypical antipsychotic in their effect on symptoms. 

  Side effects were different: patients on atypical drugs gained more weight but has fewer extrapyramidal side effects than those on typical drugs