Bulimia nervosa - Etiology

Causes
Bulimia is often less about food, and more to do with deep psychological issues and profound feelings of lack of control. Binge/purge episodes can be severe, sometimes involving rapid and out of control feeding that can stop when the sufferers "are interrupted by another person or when their stomach hurts from over-extension. This cycle may be repeated several times a week or, in serious cases, several times a day." Sufferers can often "use the destructive eating pattern to gain control over their lives".

Genetic factors
Research done in 2003, shows a link to the development of bulimia nervosa with an area on the 10p chromosome. This evidence further supports the belief that the susceptibility of developing an eating disorder (specifically bulimia) is strongly linked to genetic components. Familial links include a history of obesity, substance abuse, and depressive disorder. Twin studies also strongly support this genetic factor. While both genetics and unique environments contributed to the development of the disorder, twin studies indicate a slightly stronger effect from the genetic predisposition than from environmental circumstances. Significant rates of sexual assault and violence also indicate a possible correlation between victimization and the development of bulimia. Chemically, low levels of serotonin contribute to the continuation of the bulimic cycle; whether it is contributing to or arising from the nutritional deficiency and vomiting is still undetermined. The protein leptin decreases hunger levels in a person, and is often blocked in patients with bulimia, causing abnormal levels of hunger. Due to the binging and purging cycle the stomach is frequently stretched to an enlarged state, and over the progression of time, becomes permanently enlarged, making it necessary for more food to be in the person’s stomach to reach a level of satisfaction. This is a primary cause of the need for a bulimic to gradually increase the caloric size of their binges, as the original quantities no longer satisfy their enlarged stomach.

Environmental factors
Rates of anorexia are much more prevalent in western civilizations, to the point that the disorder is almost non-existent in eastern cultures. As western civilization is becoming a more prominent figure in other cultures, through movies and television primarily, we are seeing a dramatic increase in the incidence of eating disorders in these cultures. The disorder is also much more prevalent in the Caucasian race, though as media influences have become stronger, the disorder is becoming a rising problem in the African American and Hispanic communities. Women are also 90% of patients who suffer from this disorder, while men make up the remaining 10%. Females involved in activities which put an extreme emphasis on thinness and body type (such as gymnastics, dance, and cheerleading) are at the greatest risk for the development of eating disorders. .