Biological Explanations For AN

Question 1

Problems with genetic explanations:

Fairburn et. al (1999)

Answer 1

argues that he actual heritability of this disorder is still unknown because estimates of AN heritability is inconsistent; there’s widely contrasting statistics

these studies violate the ‘equal environments act’ also assume that MZ and DZ twins experience similar environments but this isn’t the case as MZ twins tend to be treated more similarly than DZ twins

this invalidates the claim that greater heritability of AN in MZ twins is due to greater genetic similarity

Question 2

Genetic explanations ignore the role of the media in AN:
Bulik (2004)
Vaughn and Fouts (2003)

Answer 2

genetic explanations overlook the role of the environment such as the media

the medias idealisation of ultra thin females has been deemed as a risk factor for eating disorders

Bulik: suggests genetically vulnerable individuals may seek out images of thin models in the media in order to reinforce their body image

V&F: fund that adolescent girls whose AN symptoms got worse over a period of time also reported rested reading of fashion magazines

Question 3

Research support for the role of dopamine in AN:
Kaye (2008)
Barbato et. al (2006)

Answer 3

found that food aversion, weight loss and distorted body image cognition have been related to increased dopamine activity

B: increased eye blink = greater dopamine activity and Barbato found a significant correlation between blink rate and the duration AN suggesting the dopamine-AN relationship develops over time

Question 4

Problems with the serotonin explanation:
Fergurson et. al (1999)
Kaye et. al (2001)

Answer 4

SSRIs that deal with serotonin imbalance are ineffective when used with AN patients

Fergurson: found no difference in symptom outcomes between patients taking SSRIs and patients not taking SSRIs of a similar age, body weight and symptoms

Kaye: found that wen used with recovering AN patients, these drugs were effective in preventing relapse

thus malnutrition related changes in serotonin function might negate the action of SSRIs which are only effective when weight returns to a more normal level