genetic basis

• What is the risk of developing schizophrenia for individuals with affected family members?

  Higher than those without affected family members
• What does the degree of genetic similarity indicate in relation to schizophrenia risk?

  It shows a strong relationship with shared risk
• Who conducted a large scale family study on schizophrenia risk?

  Gottesman
• What was the schizophrenia rate in the general population according to Gottesman?

  1%
• If one parent has schizophrenia, what is the likelihood their child will develop it?

  13%
• What is the likelihood of a child developing schizophrenia if both parents have it?

  46%
• What did Tsuang et al. estimate regarding first-degree relatives of schizophrenics?

  5-20 times higher risk of developing it
• What type of twins have a higher concordance rate for schizophrenia?

  Monozygotic (MZ) twins
• What does a higher concordance rate in MZ twins indicate?

  It indicates a degree of heritability
• What was the concordance rate for MZ twins found by Gottesman?

  48%
• What was the concordance rate for DZ twins found by Gottesman?

  17%
• How do MZ twins differ from DZ twins in terms of genetics?

  MZ twins have identical genetic makeup
• What does research suggest about the genetic nature of schizophrenia?

  It is polygenic and heterogeneous
• How many genetic variations did Ripke et al. find associated with schizophrenia?

  108
• What neurotransmitter's functioning is affected by candidate genes related to schizophrenia?

  Dopamine
• What evidence supports the genetic explanation of schizophrenia?

  • Joseph (2004) pooled data from twin studies
  • MZ twins had a concordance rate of 40.4%
  • DZ twins had a concordance rate of 7.4%
  • Higher MZ concordance suggests genetic influence
  • MZ concordance not 100% indicates other factors
• What are the limitations of the genetic argument for schizophrenia?

  • Difficulty separating nature and nurture
  • Shared environment may increase concordance rates
  • MZ twins treated more similarly than DZ twins
  • Shared womb environment before birth