Biological explanations

• the three biological explanations are :

  • genetic basis
  • dopamine hypothesis
  • neural correlates
• (genetic basis ) - family studies show that risk of schizophrenia increases with genetic compatibility

  • Gottesman showed that it can reach up to 48% if they are identical twins
• genetic basis a03 - limitation :

  • reductionist as there are environmental factors such as childhood trauma
• genetic basis a03 - strength

  • strong evidence shown through family studies such as Gottesman and adoption studies such as Tienari et al
  • shows - some more vulnerable than others sue to genetic makeup
• dopamine hypothesis :

  • neurotransmitters in pre frontal cortex associated with positive symptoms as neurons fire too easily
  • high numbers of D2 receptors, more dopamine binds to receptors, more neurons fire, increases positive symptoms
  • deficit of dopamine in pre frontal cortex causes negative symptoms
  • research - Leutch et al 2013 - meta analysis of 212 studies compares antipsychotics to placebo . findings - drugs more effective at reducing positive and negative symptoms
• dopamine hypothesis - a03 strength

  • evidence for role of dopamine - antipsychotic drugs reduce dopamine and reduce symptoms
  • shows - there is a biological basis for disease and behaviour
• neural correlates :

  • prefrontal cortex impaired in schizophrenia patients
  • cognitive impairments, damaged nerve connections and small or damaged hippocampus influences dopamine release and causes negative symptoms
  • research - vita et al 2012 - patients with schizophrenia compared with controls had a higher reduction in grey matter
• neural correlates a03 - limitation

  • evidence for the role of glutamate - post mortem and live scanning found high levels of glutamate in the brain of schizophrenics
  • means - other neurotransmitters may play a more central role