Biological explanations

• What does the term polygenic mean in relation to schizophrenia?

  It involves multiple genes contributing to the condition
• What does aetiologically heterogeneous mean?

  Different gene combinations can cause schizophrenia
• How many genetic variations did Ripke et al. find associated with schizophrenia?

  108 separate genetic variations
• Which neurotransmitter's functioning is implicated in schizophrenia?

  Dopamine
• What did Joseph (2004) find regarding MZ and DZ twins in schizophrenia studies?

  MZ twins had a higher concordance rate
• What was the concordance rate for MZ twins found by Joseph (2004)?

  40.4%
• What was the concordance rate for DZ twins found by Joseph (2004)?

  7.4%
• Why is the concordance rate for MZ twins not 100% significant?

  It suggests other factors influence schizophrenia
• What proportion of people with schizophrenia have no relatives with the diagnosis?

  Two-thirds
• What is a problem with the genetic argument regarding schizophrenia?

  It is hard to separate nature and nurture
• How might the environment affect concordance rates in twin studies?

  Shared environments may increase concordance rates
• What is a confounding variable in the context of schizophrenia studies?

  The shared environment complicates genetic influence
• What does the term neural correlates refer to?

  Brain abnormalities linked to schizophrenia
• What is the dopamine hypothesis in relation to schizophrenia?

  Dopamine functions differently in schizophrenia patients
• What is hyperdopaminergia?

  High dopamine levels in the subcortex
• What is hypodopaminergia?

  Low dopamine levels in the pre-frontal cortex
• How do hyper- and hypodopaminergia relate to schizophrenia?

  Both are implicated in different brain regions
• What structural brain abnormality is associated with schizophrenia?

  Enlarged ventricles
• What did Johnstone et al. (1976) find regarding ventricles in schizophrenics?

  They had enlarged ventricles compared to non-sufferers
• What is a criticism of biological explanations for schizophrenia?

  They can be biologically reductionist
• What does it mean for biological explanations to be biologically deterministic?

  They imply genetics determine the disorder
• How does biological determinism affect treatment expectations?

  It may lead to negative attitudes about recovery
• What are the key components of the dopamine hypothesis?

  • Hyperdopaminergia: high dopamine in subcortex
  • Hypodopaminergia: low dopamine in pre-frontal cortex
  • Both levels of dopamine are implicated in schizophrenia
• What are the implications of enlarged ventricles in schizophrenia?

  • Associated with loss of grey matter
  • Linked to damage in central brain areas
  • Related to negative symptoms of schizophrenia
• What are the strengths and weaknesses of biological explanations for schizophrenia?

  Strengths:

  • Supported by twin studies
  • Identifies genetic factors

  
  

  Weaknesses:

  • Biologically reductionist
  • Biologically deterministic
  • Ignores environmental influences