Evolution of Schizophrenia

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Evolution of Schizophrenia

• Sara Huesman
• April 8, 2004

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What is Schizophrenia?

• Chronic, severe and disabling brain disorder
• Approximately one percent of the population or 2
  million Americans suffer from schizophrenia
• Men usually develop the disease in their teens,
  while women develop it in their twenties

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What is Schizophrenia?

• Schizophrenia possesses a significant genetic
  component (twin studies)
• Ancient condition?
• Mesopotamia, ancient writings about aberrant
  behaviors
• Australian Aboriginal

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What is Schizophrenia?

• 1837 - Dr. Amariah Brigham first proposed that
  insanity was due to disorders of the brain
• Early 1980s - brain imaging techniques are widely
  used to look at the make-up of schizophrenics
  brains
• Large differences in a schizophrenic brain
  versus normal brain

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Sample Brain Scans

• Loss of Brain Gray Matter
• picture
• Enlarged Ventricles in Brain
• picture
• Decreased Prefrontal Brain Function
• picture

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Diagnosing Schizophrenia

• Rule out other illnesses first, also look at drug
  abuse as a possible factor
• Also sometimes it is very hard to determine which
  mental disorder a person is suffering from

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Symptoms of Schizophrenia

• Distorted Perceptions of Reality
• Hallucinations and Illusions
• Delusions
• Disordered Thinking
• Emotional Expression
• Normal versus Abnormal
• Violence Suicide?

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• Could Evolution Play a Part in Schizophrenia?

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Evolutionary Perspectives

• Divided between two major groups
• 1) Theories that assume schizophrenia to be a
  completely disadvantageous byproduct of human
  brain evolution
• 2) Theories that suggest evolutionary advantages
  associated with the condition

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Disadvantage

• Randall hypothesis -
• Neural pathways are randomly established
• Biological trial and error may lead to
  schizophrenia
• Millar hypothesis -
• Triune Brain
• Schizophrenia reflects some failure of
  integration b/n the limbus cortex

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Disadvantage

• Crows hypothesis-
• mating characteristics forced mans intelligence
  to increase
• enhanced cerebral flexibility would boost
  intelligence language
• cerebral flexibility may have led to variation in
  psychological functioning causing personality
  disorders

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Advantages

• Individual advantages
• Why is gene being saved?
• Huxley hypothesizes that these individuals have
  higher resistance to shock, allergies, and
  infection
• Kellett hypothesizes that schizophrenia could be
  beneficial to territorial animals
• inventiveness ability to tolerate low levels of
  stimulation while remaining alert

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Advantages

• Advantages to Kin
• Balanced Polymorphism
• Superior social adaptation
• Diminished incidence of viral infections
• Superior academic success creativity
• I.e. Einsteins son

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Advantages

• Group advantages
• group-splitting hypothesis of schizophrenia
• people with schizotypal traits are often used to
  start offshoot groups
• Adolph Hitler, Joan of Arc, Charles Manson

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Conclusions

• Little is known about the origins of
  schizophrenia
• Arguments between whether it is an advantage to
  humans or disadvantage
• Darwin -
• Psychology will be based on a new foundation,
  that of the necessary acquirement of each mental
  power and capacity by gradation.

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Bibliography

• Polimeni, Joseph, Jeffery P Reiss. Evolutionary
  Perspectives on Schizophrenia. Canadian Journal
  of Psychiatry. 481(34-40).
• http//www.schizophrenia.com
• http//www.schizophrenia.org

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