“Anorexia Nervosa: an Evolutionary Puzzle”, 2006-08-14 ():
[cf. 2003] Anorexia nervosa (AN) has proven difficult to explain and is especially so from an evolutionary perspective. It is widespread, has probably existed for centuries and includes a genetic component but leads to starvation, infertility and sometimes death.
An attempt to explain AN will be made using a synthesis of evolutionary ideas about responses to threat. Dietary restriction is described as a response to perceived threats of exclusion from the group, which would once have been dangerous. This can develop into AN only where the weight loss sets off an ancient adaptive response to the threat of famine. Eating again and weight gain would mean re-entering the competition for status and belonging and are therefore felt as threatening.
This synthesis can explain the unusual mix of features in AN otherwise resistant to explanation.
[Keywords: anorexia nervosa, evolutionary psychology, the need to belong, social competition, famine]
…Evolutionary ideas have been used to shed light on other psychological problems and the peculiarities of AN make it of particular interest. AN is here explained with a synthesis of ideas about response to threat. Dietary restriction is explained using the concept of social attention holding power (self-esteem) and the need to belong. Restriction may be part of an attempt to maintain status and belonging within a group when both feel under threat. Differences between females and males in response to intra-sexual competition may explain why dietary restriction, and hence AN, is more common in females. Some evolutionary models of AN have been proposed and it is suggested that two of these may work together to produce the odd mix of symptoms that is AN. When weight dips below a certain level an old adaptive response to the threat of famine is triggered thus enabling the weight loss to continue. This explains why AN is relatively rare, how restriction is achieved, why people can function at low weight, and why aspects of this are experienced in a positive way. Others may then exploit the weight loss, so that the fear of eating and returning to a normal weight is because doing so would reopen the possibility of attacks by others and bring back the risk of exclusion. Thus the restriction continues. These hypotheses are not easy to prove or disprove but may provide new ways of looking at AN and of finding more successful ways of helping people recover from this dangerous condition
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