biological explanations for schizophrenia - describe

  • Created by: Abi Crew
  • Created on: 13-05-22 12:40
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  • biological explanations for schizophrenia
    • dopamine hypothesis
      • schizophrenia said to be caused by an excess of dopamine activity in the brain Snyder (1976)
        • hyperactivity in D2 receptor = positive symptoms
        • hypofunctionality in D1 receptor = negative symptoms
      • theory proposed after observations of the effect of amphetamine, which enhances dopamine effects
        • rognli and bramness (2015)
        • amphetamine psychosis has similar symptoms to schizophrenia
      • Brain imaging studies using injections of dopamine-related chemicals have suggested that there are differences in the dopamine behaviour of schiz + non schiz.
        • L.Farde (1997)
        • Horga et al (2016)
      • Schizophrenia symptoms treated the same way as Parkinsons, which may be caused by dopamine abnormalities
        • Correll and Schenck (2008)
    • enlarged ventricles
      • Too simplistic to think of schizophrenia as just dopamine related
      • Proposed that abnormal dopamine levels could vary by brain region,
        • Davis et al. (1991)
        • frontal lobe - low levels of dopamine could explain negative symptoms
      • Scans consistently show structural abnormalities in schizophrenics
        • Differences seem to centre around ventricle size
          • naturally occurring fluid cavities in the brain
          • Weinberger et al (1980) found significant ventricular enlargement in those with schizophrenia
          • Torrey (2002) ventricles in schizophrenics 15% larger
      • HOWEVER - thought that is not the enlarged ventricles causing schizophrenia, but the loss of brain tissue that would have otherwise occupied that space


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