If anorexia is caused by a particular gene then it would be passed down through family trees. From this reason we could expect the blood relatives of anorexia sufferers to also have a high chance of developing it themselves. Evidence was found in a study by Strober and Humphrey (1987) that relatives of the eating disorder patients they studied were in fact four to five times more likely to develop anorexia than members of the general public.
Another biological explanation for anorexia is to do with damage to the lateral hypothalamus; this is the area of the brain that regulates the ‘start feeding’ process we when are hungry. A study shown that rats with brain damage to the lateral hypothalamus, didn’t eat a sufficient amount of food to maintain a stable healthy weight, could this finding also be used to explain the disorder in humans.
Your brain requires a healthy, nutritious diet to function normally. It uses a fifth of all the calories you eat. So extreme dieting can disrupt normal functions of the brain, possibly making anorexia symptoms worse. For example, when the brain is malnourished hormone levels become imbalanced causing sensitivity to the amino acid known as tryptophan which is found in almost all foods. As a result of this sensitivity the person may become extremely anxious when eating food making them starve themselves to feel calm. There is another hormone in the body that is released by the hypothalamus which tells us to ‘stop’ eating when we are full. Through starving the body the ‘appetite-reward path’ can become mixed up and instead of giving a feel of satisfaction when finishing eating, the anorexic person may feel guilt or self loathing for being full and this could make the person starve themselves to avoid those feelings.
Serotonin is a chemical released in the body that is involved in almost all behavioural changes in anorexia sufferers. Tryptophan the essential amino acid which is responsible for serotonin is found in a normal diet, this however, will be absent in individuals with anorexia due to their poor diet, thus making their serotonin levels decreased. This decrease in serotonin levels can also explain how most anorexia sufferers also suffer from the mental condition depression, which is also due to a lack a serotonin. Collier et al (1999) found that women with eating disorders were twice as likely as a control group to have an abnormal version of the gene.
Regarding the monozygotic twins having the same genes so therefore will both develop anorexia, this could be because of the twins being raised within the same environment, not the fact that they share identical genetic make-up. However this could also be said for the non-identical pair as they share the same environment through childhood. Research has proven that anorexia does have a small degree of scientific theories to help back up its biological explanations. The genetic abnormalities that have been found during studies with scientific methods, which have then been tested for reliability. An individual with anorexia is not seen as being responsible for their behaviour and is rather seen as a victim of a disorder in which they have little or no control. This removes any issues of labelling for the person. Monozygotic twins are in fact not totally identical; they have different fingerprints, handedness, therefore they can’t be used to prove that anorexia is linked to genes. The rates of the identical twins both contracting the disorder while are high, are still not 100%. This means that the environment must also play a role. While this explanation helps explain the disorder and removes issues of blame and labelling the person, the genetic explanation is not helpful in seeking treatment for someone suffering from anorexia. 
No comments:
Post a Comment