Biological explanation for AN

Question 1

What are the two areas of research for the biological explanation of AN?

Answer 1

• Genetics (family, twin and adoption studies)

- Neural (serotonin, dopamine and limbic system dysfunction)

Question 2

Why are twins studied and what has the research found?

Answer 2

MZ twins share 100% of their DNA and genes. DZ twins share 50%.
-Heritability varies from 28-74%

Question 3

What is a problem with twin studies and how can it be overcome?

Answer 3

problem disentangling nature vs nurture (twins have same environment)
adoption studies-twins brought up in different environments

Question 4

What have family studies found?

Answer 4

• first degree relatives of an AN patient are 10x more likely to develop AN
• increased risk of them developing another eating disorder
• people may inherit a genetic vulnerability to eating disorders rather than AN specifically

Question 5

What connection has been found between dopamine and AN

Answer 5

• Kaye et al (2005) used PET scans to compare dopamine activity in the brains of 10 women recovering from AN and 12 healthy women
• overactivity of dopamine receptors in the basal ganglia of AN women where dopamine plays a role in the interpretation of harm and pleasure
• AN sufferers struggle to associate good feelings with commonly pleasurable things (food)

Question 6

What connection has been found between limbic system dysfunction and AN?

Answer 6

• Lipsman et al (2015) found that neural roots of AN appear to relate to limbic system dysfunction (subcallosal cingulate and insular cortex)
• these areas usually regulate emotion
• dysfunction in these areas can lead to deficits in emotional processing which leads to pathological thoughts and behaviours typical to AN

Question 7

What is the advantage of biological explanations for eating disorders?

Answer 7

• reduce stigma around disorders by challenging the idea that it is the individual’s fault
• offer the possibility of treatments that regulate brain areas involved in the characteristic behaviours
• however it could make the individual feel powerless (that’s just how i am)

Question 8

What is the problem with the genetic explanation for AN?

Answer 8

• Fairburn et al (1999) concluded that the heritability rate for AN is still unknown
• rates of heritability vary from 28-74%
• studies also assume that twins raised in the same home have equally similar environments however MZ twins tend to be treated more similarly than DZ twins so the greater concordance in MZ twins cannot be put down to just genetics