Biological Explanation of Anorexia : Genetics

• What is the heritability estimate for anorexia?

  71%
• What does a higher frequency of anorexia in relatives suggest?

  Genes may explain anorexia's occurrence
• What percentage of MZ twins were concordant for anorexia?

  46.2%
• What percentage of DZ twins were concordant for anorexia?

  7.1%
• What personality traits are linked to anorexia?

  • Perfectionism
  • High need for order
  • Sensitivity to praise and reward
• Which gene is linked to restricting anorexia and temperament?

  1P gene
• What did Grice et al find in their study of families with anorexia?

  A genetic link on chromosome 1
• What did Bachner Melman et al discover about genes and personality traits?

  Three genes linked to perfectionism traits
• How do adoption studies contribute to understanding anorexia?

  • Separate nature and nurture influences
  • Show environmental impact on development
• What do twin studies suggest about MZ and DZ twins regarding anorexia?

  MZ twins should be more concordant than DZ twins
• What was the concordance rate for MZ twins found by Holland?

  56%
• What was the concordance rate for DZ twins found by Holland?

  7%
• Why is the objective measurement of concordance rates significant?

  It establishes a cause and effect relationship
• What is a weakness of concordance rates in twin studies?

  Never 100% concordance rates exist
• What does operant conditioning suggest about anorexia development?

  Positive and negative reinforcement influences it
• What did Wade et al find about families of anorexics?

  Frequent comments about weight were made
• What does the EPHX2 gene regulate?

  Cholesterol metabolism
• How does low serotonin relate to anorexia?

  It can lead to anxiety and depression
• What brain areas are linked to serotonin and anorexia?

  Hypothalamus and amygdala
• What does TaqA1 gene link to in anorexic patients?

  Addiction and obsessive symptoms
• What is a weakness of the biological explanation of anorexia?

  It ignores environmental contributions
• What is a strength of oversimplifying anorexia's biological factors?

  Allows detailed operationalization and study
• How do genes affect neurotransmitter levels in anorexia?

  They can disrupt dopamine function
• What happens to reward processing in anorexics?

  They feel less satisfaction from desirable foods
• What can mutations in genes lead to regarding motivation after eating?

  Lack of motivation may occur
• How do low serotonin levels affect appetite in anorexics?

  They disrupt neutral information about appetite
• What is a strength of drug treatments for anorexia?

  They target biological factors effectively
• What is a weakness of the deterministic view of genetics in anorexia?

  It suggests no free will exists
• What does the diathesis-stress model suggest about anorexia?

  • Biological predisposition exists
  • Environmental triggers influence development
  • An interactionist and idiographic approach is needed