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Biology 202
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Anorexia Nervosa and Bulimia Nervosa

Hajira Amjad

In the past few years, there has been an increase in the number of people suffering from anorexia nervosa and bulimia nervosa. These eating disorders affect mostly teenage and young adult women. It is estimated that one percent of adolescent girls suffer from anorexia and three percent suffer from bulimia. Approximately ninety percent of the victims of this disease are in this category. The remaining ten percent includes older women and young men (1). Overall, it is estimated that about five million people are afflicted with this disorder (2).

Anorexia nervosa is an eating disorder in which the victim undergoes self-starvation (4). Some behavioral signs exhibited by people suffering from anorexia include restricted eating, fear of becoming fat, and heavy exercise (3). Some of the effects on the health of the individual include weight loss in a very short period of time, irregular menstrual cycles, bone mineral loss, shrunken organs, and irregular heartbeat, which can lead to heart attacks(2) (3). Anorexics tend to be of normal weight and become withdrawn right before the onset of the illness (4).

Bulimia nervosa is another form of an eating disorder in which the victim undergoes periods of binge eating followed by self-induced vomiting. Some behavioral symptoms of such individuals includes binge eating, eating in secret, bathroom visits after meals, and use of diet pills (3). Some medical consequences of bulimia are similar to those found in anorexics and they also exhibit tooth decay, sore throat, swollen glands, and internal bleeding due to vomiting (3) (4). Bulimics tend to be a little overweight and are naturally shy and withdrawn long before the onset of bulimia (4).

The group most affected by eating disorders are generally young women. This can be attributed to the belief that thinness is a measure of beauty, as can be observed from the portrayals of women in the entertainment industry. This desire to be thin leads many young women to follow strict diets in order to attain this "ideal" figure and this in turn can result in some of these girls to develop eating disorders. Along with social factors influencing the formation of eating disorders, it has also been found that other factors, such as personality, genetics, and biochemistry, also play a role in the development of eating disorders (1).

Certain personality traits, such as low self-esteem, feelings of helplessness, and a fear of becoming fat, characterize people with eating disorders. There are also some traits that are different in anorexics and bulimics. Anorexics tend to be perfectionists, good students, and rarely disobey the wishes of their parents. By restricting their intake of food and controlling their weight, they feel they have some sense of control in their life. Bulimics on the other hand tend to be overweight individuals, who consume large amounts of food and are overcome with feelings of guilt and depression afterwards. To deal with these anxieties and other stresses, they then force themselves to purge (1).

Eating disorders also seem to run in families and so it seems that there might be a genetic predisposition towards it (1). However, it is interesting to note that most females with eating disorders are of the middle-to-upper classes (5). It seems that among the upper classes there is more of an emphasis on appearance. Instead of there being a genetic tendency towards eating disorders, it can perhaps also result from social pressures exerted by their families to look a certain way.

There is also evidence that chemical imbalances in the brain may also be responsible for the onset of eating disorders. There is a decrease in the levels of the neurotransmitters serotonin and norepinephrine, which are responsible for hormone production, in people suffering from anorexia and bulimia. These neurotransmitters also do not behave normally in individuals suffering from depression. Since patients suffering from eating disorders also suffer from depression, there may be a link between these two disorders. This can also be observed by the fact that drugs used for anti-depression, such as fluoxetine, which affects serotonin function, are also found to be effective in treating anorexia (1).

Another disorder resulting from abnormal serotonin levels is obsessive-compulsive disorder and it has been found that many patients with bulimia also display behavior characteristic of OCD. There is also an increase in the level of the hormone vasopressin in people suffering from eating disorders and OCD (1).

Research is still being conducted on other possible chemical imbalances in the brain that may be responsible for eating disorders. It has been shown that neuropeptide Y and peptide YY are responsible for eating behavior in laboratory animals. The levels of these chemicals are found to be elevated in people suffering from eating disorders. Another hormone cholecystokinin(CCK) has been found to cause laboratory animals to feel full and stop eating. It has been found that there is a decrease in the levels of CCK in bulimic women, thus explaining why these women display a bingeing pattern (1).

Treatment for eating disorders is very difficult and the method of treatments for eating disorders includes behavioral as well as drug therapy. As research continues into the chemical imbalances causing eating disorders, it seems likely that better treatments for eating disorders may result.

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WWW Sources

1)Eating Disorders

2)American Anorexia Bulimia Association, Inc.

3)The Eating Disorders Site

4)Eating Disorders

5)Serotonin and Eating Disorders




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