Genetics

• What does the genetic explanation for schizophrenia suggest?

  Schizophrenia is inherited and results from a biological process driven by the activity of certain genes, such as for brain structure development and neurotransmitter levels
• Schizophrenia is thought to be a polygenic disorder
• If schizophrenia is genetic, then we expect to see the more closely related two people are, if one person has the disorder, the more likely the other person is to have the disorder (concordance rate)
• Who used family studies to study genetic basis of sz?

  Gottesman
• What was the concordance rate for monozygotic twins (Gottesman)?

  48 %
• What was the concordance rate of dizygotic twins? (Gottesman)

  17 %
• What is the general population rate of sz?

  1 %
• What is a problem with the genetic explanation shown in Gottesman‘s study?

  Concordance rate is not 100 % in MZ so not fully genetic disorder
• Who used adoption studies to investigate genetic basis of sz?

  Tienari
• What did Tienari (2004) study?

  The biological children of schizophrenic mothers who had been adopted
• What was the percentage of sz in children adopted into psychologically healthy families? (Tienari)

  5.8 %
• What was the percentage of children who developed sz in dysfunctional families (Tienari)?

  36.8 %
• What is the conclusion of Tienari’s study?

  As the risk for both groups is far above the 1 % risk level of the general population, this suggests sz has a genetic basis. Howeber, difference between the groups also suggests a role to play for psychological factors