Anorexia nervosa: an evolutionary puzzle.
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 found in AN that are otherwise resistant to explanation.
Eating Distress Therapy Service, Department of Psychological Therapies, Chaddeslode Lodge, Shrewsbury, UK. nmgatward55@hotmail.com
Nicholas
N
Gatward
D000856:Anorexia Nervosa / Q000235:genetics* / Q000523:psychology; D005075:Biological Evolution; D005260:Female; D005824:Genetics, Behavioral; D006801:Humans; D012641:Selection, Genetic; D012725:Sexual Behavior; D012919:Social Behavior; D013217:Starvation