Biological explanations

Biological Explanations of Eating Disorders


Because eating behaviour is related to homeostatic mechanisms, theories of eating disorders in terms of neurological factors are very popular. Originally it was believed that pituitary gland damage was the cause of eating disorders, but it now seems that this was due to a confusion with another condition now known as Simmond’s disease. Other researchers have suggested the hypothalamus may be dysfunctional in people with eating disorders as this is the regulatory centre for eating behaviour. Most of the support for this idea came from non-human animal studies where animals would stop eating when given lesions in one portion of the hypothalamus. Studies have shown correlations between anorexia and changes in noradrenaline and serotonin levels in the brain, while other studies have implicated various hormones and endorphins in bulimia. Another influential theory states that people with bulimia have a heightened physiological need for carbohydrates, hence the preference for this type of food during binges.

Because eating disorders run in families, there have been suggestions that they may have a genetic basis. Holland et al (1988) investigated if there was a genetic basis to AN by comparing differnt types of twins. If there was a higher concordance rate in identical twins than non-identical twins this would be evidence for a genetic explanation.

Kendler et al (1993) have conducted a similar twin study on BN. However in this study the concordance rate for MZ twins was lower (23%).




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