Discuss Biological explanations of Anorexia Nervosa.

(8+16)

AO1 AFFH

An attempt at explaining anorexia nervosa (AN) has been explained by Guisinger’s (2003) adapted to flee famine hypothesis (AFFH). AFFH fits under the evolutionary approach, but is also a biological explanation. Guisinger proposes that AN is part of behaviours adaptive in the environment of the evolutionary adaptation (EEA). In hunter-gatherer society, there would have been prolonged periods of famine and it would have been necessary to move on regularly when food resources were exhausted. To cope with this, people would have keep active despite lack of energy. Guisinger draws a parallel with anorexics, who tend to have high activity levels and restlessness, despite the typical response to starvation being inactivity and depression. Therefore, she hypothesised, high levels of activity and a denial of hunger, necessary to migrate in times of famine, and are explanation of AN today.

AO2

Guisinger’s AFFH meets criticism. As with most research in the evolutionary approach, it is limited by its lack of direct evidence. AFFH remains a hypothesis, because it cannot be proven. Guisinger draws from her knowledge and assumptions regarding hunter-gatherer society and applies them to traits seen in sufferers of AN. Whilst there appears to be something in what she says, it is has very little scientific evidence to support it.

AO2/IDA

Another criticism of this theory is that it cannot explain inconsistencies between men and women. One thing that prevents Guisinger’s AFFH from being entirely plausible is that it cannot explain why AN is far more prevalent in women. If her hypothesis applies, then would AN not affect both sexes equally.

AO2/IDA

Another criticism of the explanation is  to how the symptoms of AN might be passed on by natural selection, particularly as they decrease fertility and could even kill the individual with this condition, this questions the validity of the explanation.  

AO2/IDA 

The theory is also highly speculative and cannot be falsified. This decreases the validity of the explanation as its not based on empirical scientific evidence, unlike other theories such as socialcultural explanations such as the influence of media which is supported by evidence such as Becker et al, thus making the theory more valid than the evolutionary explanation.

AO1 Genetics/Twin Studies 

Researchers such as Holland et al. (1984), however, have claimed that genetics are the best biological explanation of AN. Research into genetics’ role tends to come in the form of twin studies. Holland et al.’s is perhaps the most notable. They researched the genetic link by comparing MZ and DZ twins, where one twin of each pair was suffering from AN. They hypothesized that as MZ twins are genetically identical, if AN characterised entirely genetic, it should be a shared trait. Holland et al. found a concordance rate of 55% for MZ twins and of only 7% for DZ twins. The significantly higher concordance rate for MZ twins suggests a genetic involvement in anorexia nervosa, but clearly it is not the only component in place. If it was entirely genetic, the concordance rate would surely have been 100%.

AO2 

However, Holland et al’s research has been supported by other research. Kendler et al. (1991) found similar results in their twin study. Further research has found genetic contribution to anorexia nervosa is between 50-80% (Klump et al., 2001; Bulik et al., 2006).

IDA 

There is gender bias in a lot of the research carried out into eating disorders as most of the research has concentrated on the study of women. However according to recent studies, 25% of men suffer from an eating disorder. This demonstrates that anorexia is not exclusively and female problem.

IDA 

A criticism of this theory is that it is highly deterministic and claims that our behaviour is predetermined by our genes, in this case the theory is suggesting that anorexia is caused by our genetics and people who share genetics with someone with anorexia is already predisposed to the condition. However this ignores free will in which people can choose how they want to eat, in which it largely agreed that anorexia is a psychological condition and can be better explained by media as an influence for anorexia.