biological approach

• genetics

  genes are inherited and can include neurotransmitter levels
• family studies

  • Gottesman (1991) family study
  • found genetic similarities increase sz risk, in identical twins who share 100% DNA, 48% increased risk
  • in parents who share 50% DNA, 6% increased risk
  • but this is correlational data which also includes a shared environment
• candidate genes

  • sz is polygenic (lots of linked genes)
  • Ripke did a meta analysis of genetic studies and found 108 variations. 37,000 out of 113,000 had sz
  • meaning sz has many factor origins
• role of mutation

  • increased sz risk even with no inheritance
  • radiation, poison, virus, age of dad
  • Brown(2002) found if dad was below 25, 0.7% increase and if he was above 50, 2% increase
• neural correlates

  patterns of brain activity occurring with an experience
• original DA hypothesis

  • hyper dopaminergia is linked to sz symptoms
  • high DA is linked to speech poverty in Broca's area
  • Seeman, antipsychotics which reduce DA produced Parkinson's symptoms
• updated DA hypothesis

  • Davis found low dopamine levels in hypodopaminergia in brain's cortex linked to sz symptoms
• real-life application

  • genetic counselling, if parents have schizophrenic relatives, they can seek counselling to see if their child is at risk
  • however, the counselling figure is just a guess, not 100% accurate
  • also doesn't consider environment
• environmental factors- limitation

  • smoking canabis as a teen increases sz by 17.4% (psychological influences)
  • nurture over nature and childhood trauma icreasesrisk by 67%