bio explanations

• lindostroem et al (1999) 


  gave radioactive L-dopa (amino acid needed to make dopamine) and observed uptake using PET scans, uptake faster in schizophrenia patients than in control group, schizophrenia patients make more dopamine
• kessler et al (2003)


  injected patients with radioactive drug which binds to D2 receptors, found more receptors in schizophrenic patients than in control
• falkai et al (1988) 


  post mortem showed higher amounts of D2 receptors in schizophrenic patients
• cocaine

  blocks removal of dopamine, dopamine accumulates in the synapse and amplifies the signal to receiving neurons
• biologically reductionist


  doesn’t consider other neurotransmitters

  glutamate - involved with anxiety regulation

  bradford (2009) - low level of glutamate in the brain is involved with the development of schizophrenia
• taking a reductionist approach


  led to the development of drug treatments for schizophrenia
• hyperdopaminergic 


  high levels of dopamine

  for example, excess of D2 receptors in Broca’s area leading to speech poverty
• hypodopaminergic 


  low levels of dopamine
• dopamine hypothesis


  suggests that too high or low levels of dopamine has an influence of the development in schizophrenia
• neural correlates


  measurements of the structure or function of the brain in conjunction to schizophrenia
• enlarged ventricles 


  people with schizophrenia have larger ventricles, patients found to have lighter brains
• torrey (2002) 


  patients with schizophrenia have ventricles 15% larger than normal
• enlarged ventricles 


  associated with damage to central areas of the brain and the prefrontal cortex
• suddath et al (1990)

  MRI of MZ twins (one was schizophrenic), found that 12/15 of schizophrenic twins had enlarged ventricles and differences were noticeable
• issues with causation 


  brain differences may be due to past life experiences such as drug abuse

  schizophrenia may create brain differences or brain differences lead to schizophrenia

  tells us little about cause and effect
• genetic vulnerability 


  suggests there is a genetic component to the development of schizophrenia
• twin studies

  gottesman and shields - MZ twins found with the concordance rate of 48%
• adoption studies

  heston (1966) - 47 adopted children with biological mothers with schizophrenia and 16% of the children were eventually diagnosed with schizophrenia
• not a complete explanation

  not 100%

  must be an environmental component as suggested with diathesis stress model