Anorexia Nervosa

Anorexia nervosa is an eating disorder characterized by immoderate food restriction and irrational fear of gaining weight, as well as a distorted body self-perception. It typically involves excessive weight loss. Anorexia nervosa usually develops during adolescence and early adulthood. Due to the fear of gaining weight, people with this disorder restrict the amount of food they consume. This restriction of food intake causes metabolic and hormonal disorders. Outside of medical literature, the terms anorexia nervosa and anorexia are often used interchangeably; however, anorexia is simply a medical term for lack of appetite and people with anorexia nervosa do not in fact, lose their appetites.

People suffering from anorexia have extremely high levels of ghrelin (the hunger hormone that tells the brain when it is time to eat) in their blood. The high levels of ghrelin suggests that their bodies are trying to desperately switch the hunger aspect on, however, that hungers 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.

Anorexia nervosa has many complicated implications and may be thought of as a lifelong illness that may never be truly cured, but only managed over time. Anorexia nervosa is characterized by low body weight, inappropriate eating habits and obsession with having a thin figure. Individuals suffering from it may also 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 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. Anorexia nervosa is characterized by the fear of gaining weight. Those suffering from this disorder often view themselves as "too fat" even if they are already underweight. People with anorexia nervosa continue to feel hunger, but 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.

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 10 times more females than males.

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.