A single cause for anorexia nervosa has not been discovered. While some researchers believe social pressures affect an anorexic's body image, others believe psychological disorders or physical problems (such as serotonin imbalances) may be to blame.
While no exact cause of anorexia is known, here are the factors thought most likely to be responsible for the eating disorder:
The idea that public opinion and social pressure causes anorexia nervosa has been considered as a possible cause for some time. Many western industrialized cultures equate thinness with an ideal body image. Thinness and low body weight is equated with beauty and success. By extension, overweight or obese individuals are equated with ugliness, a lack of success, and an implied lack of self-control.
However, the social vision of the "perfect" body is simply not attainable for most people. Simple biology prevents the average American woman, who weighs 140 lbs and stands 5'4" tall, from conforming to a body image idealized by fashion models who stand 5'11" tall and weigh only 117 lbs. (it's worth noting that fashion models, under intense pressure to conform to this ideal body image, are at higher than normal risk of anorexia nervosa and other eating disorders).
The conflict between actual and desired body image is thought to trigger anorexia in some people. Teenagers are especially vulnerable to social and peer pressure, which may explain why peak rates of anorexia occur in the teen years. According to statistics from the National Eating Disorders Association, by the time they reach college, 92 percent of young women have tried to control weight through dieting, and 22 percent "often" or "always" diet.
However, while there is no question that social pressure and idealized body image plays a role in anorexia nervosa, social pressure alone probably does not cause the eating disorder. The majority of people exposed to the social message of the "ideal body" do not develop anorexia nervosa. Nor does every woman unhappy with her body image (eighty percent of American women are dissatisfied with their body image) become anorexic. It seems that social pressure may be a trigger for anorexia, but some other underlying problem must be present for this to occur.
Somewhat related to social pressure, is the theory that family dynamics may affect teen health and contribute to eating disorders. Anorexics often come from families with high levels of rigidity or control. Teen health may be affected by these restraints as the teenager's need to assert independence develops. Anorexia can be seen as a method of asserting self-control over body image, and asserting independence from the family group.
If the family is dysfunctionally overprotective and close, individual family members can become dependant on the family for identity. A child or teen who relies on her place in the family for identity may develop anorexia due to a fear of growing up. Teen health problems associated with anorexia nervosa include growth retardation and a delay in physical maturation, which allows the teen to continue her role of "child" in the family unit.
Other anorexics come from families that overemphasize appearance, fitness and thinness, or have parents who consistently criticized their body shape or weight. A family history of sexual abuse, physical abuse, or substance abuse increases the risk of anorexia nervosa.
Psychologically, certain personality traits increase the risk of anorexia. People with anorexia nervosa often have low self-esteem, and suffer from feelings of insufficiency. They may have rigid thought patterns, and have an almost compulsive need to control their lives. Externally, anorexics may appear as effective people going all-out in all areas of their lives, and striving to overachieve in careers, sports, or schoolwork as well as weight loss.
People with anorexia nervosa are often perfectionists, who are overly critical of themselves. Anorexics also tend to socially isolate themselves, and to avoid conflict when possible.
Anorexia nervosa often arises alongside other mental health disorders, including clinical depression, anxiety, and symptoms of obsessive compulsive disorder. Whether depression and other mental health disorders trigger anorexia or not is difficult to determine. Starvation results in a number of psychological health complications, including depression, anxiety, social isolation, mood and personality changes, an obsessive thinking. Mental health disorders in anorexics may be a result of anorexia nervosa, rather than the cause of the eating disorder.
Traumatic life changes have also been known to trigger anorexia nervosa, although this is only thought to occur if the individual is already "pre-disposed" to developing the eating disorder. Such life changes may include:
Many people experience these life events for the first time in their teen years, which may partially explain why anorexia affects teens more often than adults.
Once anorexia nervosa develops, the eating disorder tends to reinforce itself. Positive comments on weight loss by peers or family members in the initial stages of anorexia may reinforce the desire to continue losing weight. The eating disorder may give the anorexic a feeling of power, self-control, or virtue.
Evidence suggests that physical changes to normal brain function may trigger anorexia nervosa. For instance, defects in the brain's hypothalamus may affect an individual\'s perceptions of appetite, hunger, and stomach fullness.
Genetically, people with close family members who are anorexic are more likely than normal to develop anorexia nervosa. A study at Maudsley Hospital in London, England, discovered that anorexics are twice as likely to have gene variations in the brain's serotonin receptors, implying a connection between serotonin and anorexia.
Serotonin is a brain chemical that plays a role in the control of emotions. Serotonin is also a factor in sexual response, impulse control, anger, sleep patterns, depression, anxiety, and hunger perceptions. Serotonin imbalances are associated with clinical depression and anxiety, two mental health disorders often found with anorexia nervosa.
The genetic variant in serotonin receptors found in anorexics may predispose them to high levels of serotonin. At high levels, serotonin can lead to health disorders such as anxiety. Serotonin levels decrease without access to food, so the self-starvation associated with anorexia will leave the person feeling calmer. As starvation reduces serotonin to very low levels, depression may set in.
Once the person eats again, serotonin levels rise again because the body requires certain amino acids to manufacture serotonin. The increase in serotonin may re-trigger anxiety symptoms. Some researchers fear this causes a vicious cycle in people predisposed to anorexia nervosa. Over time, the anorexic subconsciously learns to avoid anxiety by avoiding food thereby maintaining low serotonin levels.
So again, what causes anorexia? While the search for answers continues, researchers are beginning to understand how complicated the question is. At present, most researchers believe that anorexia results from a number of factors. Social pressure, mental health disorders, or sudden life changes appear to trigger an as-yet undetermined predisposition for anorexia. Whether this cause is physical or psychological remains to be determined. If serotonin levels are indeed discovered to be the catalyst for anorexia, the answer may bridge physical and psychological causes.
BBC News. (2000, July 5). Anorexia found in rural Africa.
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