Officially, anorexia is estimated to be the third most common chronic condition among adolescent girls, but many scholars believe that official statistics does not reflect all incidents of this disorder. The true occurrence of anorexia may be times higher if one takes into consideration unreported or undiagnosed cases (Misra et al, 2004).
DSM-IV identifies two types of anorexia nervosa: food restricting type, and binge eating (purging). The most common characteristic of the restricting type is substantial reduction in calories intake (normally to 300 to 700 kcal per day) and intensive physical overexercising. By contrast, in the binging type intake of calories may be either small or as high as several thousand followed by purging - self-induced or pharmacologically conditioned vomiting (Yager and Andersen, 2005: 1481). Health complications resulting from either type of this eating disorder affect practically all biological systems of human organism.
Anorexia nervosa is reported to entail a number of major and minor health consequences. First of all, this disorder is associated with a 5.6 percent mortality rate which is "the highest among all psychiatric conditions" (Misra et al, 2004). Besides, anorexia nervosa typically causes "loss of subcutaneous fat tissue, orthostatic hypotension, bradycardia, impaired menstrual function, hair loss, and hypothermia" (Yager and Andersen, 2005: 1481), coupled serious changes in functioning of organism, namely in hematologic aspect and bone metabolism (Misra et al, 2004). Though these changes are not considered life-threatening, they probably contribute seriously to the high mortality rate associated with anorexia.
While health consequences of anorexia nervosa are known and clear, the cause of anorexia nervosa isn't fully understood at present. Possible causes of this eating disorder are: destructive influence of family and society, genetic (inherited) factors, brain dysfunction, neurotransmitter levels imbalances, etc. However, the most common opinion is that anorexia develops due to a combination of causes: "The causes [of anorexia nervosa] appear to be multifactorial, with determinants including genetic