A03

• X reductionist?

  • bio exp - caused by genetics,high/low levels of dopamine & changes to brain activity
  • fails to recognise importance of environmental factors - upbringing
  • diathesis stress model better exp - biological vulnerability to sz & stress trigger are necessary to develop sz
  • other factors play role in sz
  • more appropriate to use interactionist approach that people may be biologically predisposed to sz but its not there until theres an adverse environmental trigger that sz symptoms manifest
  • its interaction of nature & nurture rather than just product of our innate genetic pre disposition
• X issues with determining cause & effect?

  • not clear whether changes to brain activity causes sz
  • or whether brain changes occur as a result of getting disorder
  • cant be concluded whether its enlarged ventricles that cause symptoms of sz/if symptoms of sz cause enlarged ventricles
  • may be 3rd intervening variable - upbringing/family dysfunction that causes both changes to brain activity & symptoms of sz
  • internal
  • cannot establish cause & effect between brain ventricle size & sz or whether other variables also have an effect
• X not everyone responds to drugs - neural?

  • research shows typical antipsychotic drugs that work by reducing dopamine only benefits 65% of people
  • population validity
  • if increased levels of dopamine were only cause of sz treatment should work for 100%
  • may be other explanations & not just due to imbalance of excitatory nt
  • not everyone experiences same + symptoms
  • difficult to generalise concept to all individuals with sz
• * evidence to support from curran 2004 - neural explanation?

  • found that people who take amphetamines have increase in sz symptoms & increases level of dopamine in brain
  • antipsychotic drugs work by reducing dopamine decreases symptoms of sz
  • shows high levels of dopamine linked to causing sz in particular + symptoms
  • shows dopamine must be involved in cause of symptoms due to excitatory nature positively charged nt & symptoms which add to individuals usual functioning
• * evidence to support from tienari 2004 - genetic?

  • if child whose biological mother has sz was adopted there was 10% higher chance they would develop disorder
  • compared to those adoptees whos biological mother didnt have sz
  • having parent with sz increases likelihood that individual will develop sz by inheriting their genes
  • shows genetics do play role in development of sz
  • when you have biological parent with sz chances of having disorder increase
  • support nature argument - bio factors more important than environmental causes
• * evidence to support from gottesman - genetic?

  • reviewed 40 twin studies & found 48% concordance rate for mz twins
  • 17% concordance rates for dz twins
  • as mz twins share 100% genes & dz share 50% findings suggest genetics influence sz
  • those genetically similar more likely to have sz compared to those less genetically similar
  • shows that higher amount of genes shared increased biological risk factor of developing sz
  • adds to nature argument - physical basis
• X concordance rates not 100%?

  • as do not match exact amount of genes must be other environmental factors such as family dysfunction that could play a role