Steven Crane Compiled Section Handouts. Human Behavioral Biology 2012

What role does early life experience play in schizophrenia?

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  There's only 50% concordance in MZ twins, so you know at least 50% of the variation is due to environmental factors! Genes, again, are far from deterministic in this disease.
  

How do we know stress plays a role in developing schizophrenia?

• Dutch Hunger Winter fetuses have 2-3x the schizophrenia incidence. Same with the Chinese Famine of 1960.

• Mothers with major complications during labor have children with higher incidence of schizophrenia.

• Stressing rats prenatally causes more dopamine releasing terminal density in the frontal cortex

Does being schizophrenic make you more at risk for viral infections?

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  No, seems to be the opposite: viral exposure often precedes the onset of symptoms
  
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  Perhaps immune defenses against pathogens work differently in schizophrenia (see above for MHC link)
  

Which parasite is specifically implicated?

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  Toxoplasma gondii: exposure precedes onset of symptoms.
  

Can parenting style be schizophrenogenic?

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  No evidence! Despite a long history in psychiatry of telling mothers they caused it with their "conflicting emotional demands along with a cold, aloof style."
  

But what link do families where some members have schizophrenia share?

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  This subtle communicative style: telegraphic/vague communicative patterns that everybody understands perfectly in the family.
  
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  Descriptions of inkblots are readily understood between family members where schizophrenia has some influence. Caveat with all this: "There is no particularly satisfying model at this point that integrates the genetics, neurobiology, developmental features and symptoms of schizophrenia." -extended notes