Biological explanation

• Biological explanation of SZ-

  Genetic explanation-

  • hereditary
  • Twin studies = concordance rates (Monozygotic=100%, Dizygotic=50%)
  • candidate genes = PCM1 = SZ (mutation increases the risk - Gurling)
• Biological explanations for SZ-

  • Grottesman - 1991
  • large scale family studies
  • MZ twins = 48% SZ - more genes shared = higher risk of SZ in both participants
  • DZ twins = 17% SZ - less genes lower chance of SZ
  • no 100% chance of SZ = genetical component
  • relationships show the correlation and therefore causation of SZ
• Biological explanation for SZ-

  • Polygenic - gene combo - NRG1/3 - different combination of candidate genes = SZ
  • Ripke 2014- meta-analysis, 108 separate genetic variations = large variation risk = hard to identify/treat
• Biological explanation for SZ-

  S- genetic counselling - parents have informed understanding of the risk of SZ

  CPS- biological deterministic - genetically based, no control

  CPW- no control = negative implication of blame

  W- polygenic nature = hard identification/prediction

  W- partial explanation - concordance rates aren’t full (48%) = biological reductionism CPW

  CPS- objective scientific testing = scientific credit
• Biological explanation for SZ-

  Neural explanation - evaluations

  S- biological reductionist - singular units of causation, objective research

  CPS- biological reductionist - treatments to treat imbalances - drug therapy

  CPW- treatment fallacy - effective drugs don’t mean dopamine is the cause - evidence of other NT - Glutamate/serotonin
• Biological explanations for SZ-

  Neural explanation - brain structures = SZ

  Old DA hypothesis = excessive dopamine in sub-cortex - hyperdopamineriga, broca‘s area = speech poverty, auditory hallucinations

  New DA hypothesis = too little dopamine in cortex (Davi’s 1991) - hypodopamingergia, prefrontal cortex = logical reasoning/decisions effected, avolition