Drug therapy

• Antipsychotics - these are drugs used to reduce intensity of symptoms (especially positive) of psychotic conditions like SZ
• All antipsychotics work by reducing dopaminergic transmission - reducing the action of dopamine in areas of the brain associated with schizophrenic symptoms
• Typical antipsychotics - developed in 1950's and are used to combat the positive symptoms such as hallucinations and thought disturbances

  They are dopamine antagonists
• Atypical antipsychotics - also combat positive symptoms but they are also claimed to have some beneficial effects on the negative symptoms as well.

  Developed in the 1970's and typically target a range of neurotransmitters such as dopamine and serotonin
• Typical antipsychotics

  They bind to but do not stimulate dopamine receptors, blocking dopamine action

  By reducing stimulation of dopamine system in mesolimbic pathway, this can help eliminate the hallucinations and delusions
• Typical antipsychotics

  Hallucinations and delusions usually diminish within a few days of beginning medication, other symptoms may take several weeks before significant improvements
• Typical antipsychotics

  Unfortunately to block dopamine receptors in the mesolimbic pathway, other dopamine receptors in other areas of the brain need to be blocked too, leading to undesirable side effects.
• Atypical antipsychotics

  Three main differences compared to typical:

  • Carry lower risk of extrapyramidal side effects
  • Have a beneficial effect on negative symptoms and cognitive impairment
  • Suitable for treatment resistant patients
• Atypical antipsychotics

  They also bloc dopamine receptors. However they only temporarily occupy the dopamine receptors and then rapidly dissociate to allow normal dopamine transmission.

  The rapid dissociation is thought to be responsible for the lower levels of extrapyramidal side effects found with these drugs compared to conventional drugs.
• Atypical antipsychotics have little effect on the dopamine systems that control movements and therefore tend to not cause movement problems found with typical antipsychotics
• Another difference is that typical antipsychotics block only D2 receptors, whereas atypical antipsychotics have a stronger affinity for serotonin receptors and a lower affinity for D2 receptors
• AO3 - antipsychotics vs placebo

  A study carried out a met analysis involving nearly 6000 patients. All patients were either on typical or atypical antipsychotics. Some of these patients were taken off the drug and given placebo instead and other remained on the drug

  Within 12 months, 64% of those patients who had been given the placebo had relapsed compared to 27% who stayed on the antipsychotic
• AO3 - atypical

  Study found that clozapine was more effective than typical and other atypical antipsychotics and it is effective in 30-50% of treatment resistant patients
• AO3

  A study was carried out to examine the efficacy and side effects of typical v atypical drugs in early phase treatment for SZ.

  Found no significant differences in terms of symptoms but found differences in the type of side effects experienced
• AO3 - side effects

  Typical antipsychotics can sometimes cause movement problem for the patient (extrapyramidal effects). More than half patients taking typical drugs experience these problems

  Tardive dyskinesia - side effect where there are involuntary movements of tongue, face and jaw. Very distressing
• AO3 - motivational deficits

  When people are given antipsychotic medication it reinforces the view that there is something biologically wrong with them.

  So they are not motivated to look at other reasons and explanations that may also contribute to their SZ