Anorexia nervosa is characterized by low body weight, inappropriate eating habits, obsession with having a thin figure, and the fear of gaining weight. It is often coupled with a distorted self image which may be maintained by various cognitive biases that alter how the affected individual evaluates and thinks about her or his body, food and eating. Those suffering from anorexia often view themselves as "too fat" even if they are already underweight. They may practice repetitive weighing, measuring, and mirror gazing, alongside other obsessive actions to make sure they are still thin, a common practice known as "body checking".
Anorexia nervosa most often has its onset in adolescence and is more prevalent among adolescent females than adolescent males. However, more recent studies show the onset age has decreased from an average of 13 to 17 years of age to 9 to 12. While it can affect men and women of any age, race, and socioeconomic and cultural background, anorexia nervosa occurs in ten times more females than males.
People with anorexia nervosa continue to feel hunger, but they deny themselves all but very small quantities of food. The average caloric intake of a person with anorexia nervosa is 600–800 calories per day, but extreme cases of complete self-starvation are known. It is a serious mental illness with a high incidence of comorbidity and similarly high mortality rates to serious psychiatric disorders. People suffering from anorexia have extremely high levels of ghrelin (the hunger hormone that signals a physiological desire for food) in their blood. The high levels of ghrelin suggests that their bodies are trying to desperately switch the hunger aspect on; however, that hunger call is being suppressed, ignored, or overridden. Nevertheless, one small single-blind study found that intravenous administration of ghrelin to anorexia nervosa patients increased food intake by 12–36% over the trial period.
The term anorexia nervosa was established in 1873 by Sir William Gull, one of Queen Victoria's personal physicians. The term is of Greek origin: an- (ἀν-, prefix denoting negation) and orexis (ὄρεξις, "appetite"), thus meaning a lack of desire to eat. However, while the term "anorexia nervosa" literally means "neurotic loss of appetite", the literal meaning of the term is somewhat misleading. Many anorexics do enjoy eating and have certainly not lost their appetites as the term "loss of appetite" is normally understood; it is better to regard anorexia nervosa as a self-punitive addiction to fasting, rather than a literal loss of appetite.
Media are among the principal social agents in many societies around the world. Television, magazines, newspapers, radio, cinema, advertising, the Internet, and other so-called "new media" or "new technologies" are the principal factors behind body dissatisfaction, concerns about weight, and disordered eating behaviour. Mass media interventions frequently offer a distorted vision of the world, and it may be difficult for children and adolescents to distinguish whether what they see is real or not, so that they are more vulnerable to the messages transmitted. Field, Cheung, et al.'s survey of 548 preadolescent and adolescent girls found that 69% acknowledged that images in magazines had influenced their conception of the ideal body, while 47% reported that they wanted to lose weight after seeing such images. There was also the survey by Utter et al. who studied 4,746 adolescent boys and girls demonstrating the tendency of magazine articles and advertisements to activate weight concerns and weight management behaviour. He discovered that girls who frequently read fashion and glamour magazines and girls who frequently read articles about diets and issues related to weight loss were seven times more likely to practice a range of unhealthy weight control behaviours and six times more likely to engage in extremely unhealthy weight control behaviours (e.g., taking diet pills, vomiting, using laxatives, and using diuretics) from magazines, websites that stress the message of thinness as the ideal have surfaced the internet and has managed to embed itself as an increasing source of influence. The possibility that pro-anorexia websites may reinforce restrictive eating and exercise behaviours is an area of concern. Pro-anorexia websites contain images and writing that support the pursuit of an ideal thin body image. Research has shown that these websites stress thinness as the ideal choice for women and in some websites ideal images of muscularity and thinness for men It has also been shown that women who had viewed these websites at least once had a decrease in self-esteem and reports also show an increased likelihood of future engagement in many negative behaviours related to food, exercise, and weight. Evidence of the value of thinness in majority U.S culture is found in Hollywood's elite and the media promotion of waif models in fashion and celebrity circles (e.g. Nicole Richie, Mary Kate Olsen, Kate Moss, and Lady Gaga).
Not only does starvation result in physical complications, but mental complications as well. It has been shown that eating disorders such as anorexia nervosa are reinforced by reward and attention. P. Sodersten and colleagues suggest that effective treatment of this disorder depends on re-establishing reinforcement for normal eating behaviours instead of unhealthy weight loss.
Anorexia nervosa is classified as an Axis I disorder in the Diagnostic and Statistical Manual of Mental Health Disorders (DSM-IV), published by the American Psychiatric Association. The DSM-IV should not be used by laypersons to diagnose themselves.
- DSM-IV-TR: diagnostic criteria for AN includes intense fear of gaining weight, a refusal to maintain body weight above 85% of the expected weight for a given age and height, and three consecutive missed periods and either refusal to admit the seriousness of the weight loss, or undue influence of shape or weight on one's self-image, or a disturbed experience in one's shape or weight. There are two types: the binge-eating/purging type is characterized by overeating or purging, and the restricting type is not.
- Criticism of DSM-IV There has been criticisms over various aspects of the diagnostic criteria utilized for anorexia nervosa in the DSM-IV. Including the requirement of maintaining a body weight below 85% of the expected weight and the requirement of amenorrhea for diagnosis; some women have all the symptoms of AN and continue to menstruate. Those who do not meet these criteria are usually classified as eating disorder not otherwise specified; this may affect treatment options and insurance reimbursments. The validity of the AN subtype classification has also been questioned because of the considerable diagnostic overlap between the binge-eating/purging type and the restricting type and the propensity of the patient to switch between the two.
Webliography:
http://en.wikipedia.org/wiki/Anorexia_nervosa
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