Biological explanations for schizophrenia

• What does the genetic basis for schizophrenia state?

  Genetic similarity affects schizophrenia likelihood
• What did Gottesman’s (1991) family study find about MZ twins and schizophrenia risk?

  MZ twins have approximately 48% shared risk
• What did Gottesman’s (1991) family study find about DZ twins and schizophrenia risk?

  DZ twins have approximately 17% shared risk
• What did Gottesman’s (1991) family study find about general siblings and schizophrenia risk?

  Siblings have approximately 9% shared risk
• Why is dopamine believed to be involved in schizophrenia?

  Dopamine affects brain systems related to symptoms
• What is hyperdopaminergia?

  High levels of dopamine activity in subcortex
• What symptoms is hyperdopaminergia associated with?

  Hallucinations and speech poverty
• What is hypodopaminergia?

  Low levels of dopamine activity in prefrontal cortex
• What are neural correlates?

  Brain structures or functions linked to schizophrenia, such as dopamine (DA) levels.
• What is avolition?

  Lack of motivation for day-to-day activities
• What part of the brain is avolition associated with?

  Ventral striatum with low activity levels
• What part of the brain are hallucinations associated with?

  Superior temporal gyrus with lower activation levels
• What are candidate genes in schizophrenia research?

  Candidate genes are specific genes thought to increase schizophrenia risk, particularly those linked to neurotransmitters like dopamine.
• Why is schizophrenia considered polygenic?

  Multiple genes contribute to schizophrenia rather than a single gene, making it a polygenic disorder.
• What does it mean that schizophrenia is ‘aetiologically heterogeneous’?

  Different genetic and environmental combinations can lead to schizophrenia.
• How do antipsychotic drugs support the dopamine hypothesis?

  They reduce dopamine activity and alleviate schizophrenia symptoms, similar to how dopamine-lowering treatments help Parkinson’s disease.
• What did Davis et al. (1991) propose about dopamine in schizophrenia?

  Schizophrenia involves both high DA in some areas (subcortex) and low DA in others (prefrontal cortex).
• What is the dopamine hypothesis

  The dopamine hypothesis suggests that schizophrenia symptoms are caused by abnormal dopamine activity in the brain.
• What are genetic correlates?

  specific genes / genetic variations that are linked to an increased risk of developing schizophrenia
• What are neural correlates?

  Differences in brain structure/function that are associated with schizophrenia symptoms