biological explanations

• What does a higher concordance rate in MZ twins suggest?

  Greater similarity due to genetic factors
• What was the concordance rate for MZ twins in schizophrenia studies?

  40.4%
• What was the concordance rate for DZ twins in schizophrenia studies?

  7.4%
• Why are adoption studies used in schizophrenia research?

  To disentangle genetic and environmental influences
• How many adoptees were studied by Tienari et al.?

  164 adoptees
• What percentage of adoptees with schizophrenic biological mothers were diagnosed with schizophrenia?

  6.7%
• What percentage of control adoptees were diagnosed with schizophrenia?

  2%
• What conclusion did Tienari et al. reach regarding genetic liability to schizophrenia?

  It had been decisively confirmed
• What are the key differences between monozygotic and dizygotic twins in genetic studies?

  • MZ twins: genetically identical
  • DZ twins: share 50% of genes
  • MZ twins show higher concordance rates for traits
• What are the implications of findings from twin and adoption studies on schizophrenia?

  • Suggests genetic factors play a significant role
  • Highlights the importance of environmental influences
  • Supports the use of both types of studies for understanding schizophrenia
• What is the risk of schizophrenia for MZ twins according to Gottesman (1991)?

  48%
• What is the risk of schizophrenia for DZ twins according to Gottesman (1991)?

  17%
• How does genetic relatedness affect the risk of schizophrenia?

  Higher relatedness increases schizophrenia risk
• What type of genetic influence is schizophrenia associated with?

  It is polygenic
• What are neural correlates in the context of schizophrenia?

  Patterns of brain structure or activity linked to schizophrenia
• What does the dopamine hypothesis suggest about schizophrenia?

  Dopamine levels work differently in schizophrenia patients
• What is associated with schizophrenia regarding dopamine levels?

  Unusually high levels of dopamine
• Which symptoms of schizophrenia are particularly associated with high dopamine levels?

  Positive symptoms
• How do messages from neurons that transmit dopamine behave in schizophrenia?


  They fire too easily or too often
• What is thought to lead to hallucinations in schizophrenia?

  Abnormally high levels of D2 receptors
• What is the result of more dopamine binding in schizophrenia?

  More neurons firing
• What are the two main types of symptoms in schizophrenia?

  Positive and negative symptoms
• What did Davis and Khan (1991) propose about dopamine levels in schizophrenia?

  Both high and low levels are involved
• What is hyperdopaminergia?

  Too much dopamine activity
• What is hypodopaminergia?

  Too little dopamine activity
• What are the key components of the dopamine hypothesis related to schizophrenia?

  • High dopamine levels linked to positive symptoms
  • Low dopamine levels linked to negative symptoms
  • Abnormal dopamine receptor activity
• What are the implications of Gottesman's findings on twin studies for understanding schizophrenia?

  • Genetic factors play a significant role
  • MZ twins have higher risk than DZ twins
  • Suggests a polygenic basis for the disorder