Anorexia enrviosa

ANOREXIA NERVOSA
The term anorexia nervosa is derived from the Greek term for “loss of appetite” and a Latin word implying nervous origin. Anorexia nervosa is a syndrome characterized by three essential criteria. The first is a self-induced starvation to a significant degree; the second is a relentless drive for thinness or a morbid fear of fatness; and the third is the presence of medicalsigns and symptoms resulting from starvation. Anorexia nervosa is often associated with disturbances of body image, the perception that one is distressingly large despite obvious thinness. In the text revision of the fourth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), anorexia nervosa is characterized as a disorder in which persons refuse to maintain a minimallynormal weight, intensely fear gaining weight, and significantly misinterpret their body and its shape. DSM-IV-TR also notes that the term anorexia (“lack of appetite”) is misleading because loss of appetite rarely occurs in the early stage of the disorder.
Approximately half of anorexic persons will lose weight by drastically reducing their total food intake. The other half of these patientswill not only diet but will regularly engage in binge eating followed by purging behaviors. Some patients routinely purge after eating small amounts of food. Anorexia nervosa is much more prevalent in females than in males and usually has its onset in adolescence. Hypotheses of an underlying psychological disturbance in young women with the disorder include conflicts surrounding the transitionfrom girlhood to womanhood. Psychological issues related to feelings of helplessness and difficulty establishing autonomy have also been suggested as contributing to the development of the disorder. Bulimic symptoms can occur as a separate disorder (bulimia nervosa, which is discussed in Section 23.2) or as part of anorexia nervosa. Persons with either disorder are excessively preoccupied withweight, food, and body shape. The outcome of anorexia nervosa varies from spontaneous recovery to a waxing and waning course to death.

Epidemiology
Eating disorders of various kinds have been reported in up to 4 percent of adolescent and young adult students. Anorexia nervosa has been reported more frequently over the past several decades, with increasing reports of the disorder in prepubertalgirls and in boys. The most common ages of onset of anorexia nervosa are the midteens, but up to 5 percent of anorectic patients have the onset of the disorder in their early 20s. According to DSM-IV-TR, the most common age of onset is between 14 and 18 years. Anorexia nervosa is estimated to occur in about 0.5 to 1 percent of adolescent girls. It occurs 10 to 20 times more often in females than inmales. The prevalence of young women with some symptoms of anorexia nervosa who do not meet the diagnostic criteria is estimated to be close to 5 percent. Although the disorder was initially reported most often among the upper classes, recent epidemiological surveys do not show that distribution. It seems to be most frequent in developed countries, and it may be seen with greatest frequencyamong young women in professions that require thinness, such as modeling and ballet.

Comorbidity
Anorexia nervosa is associated with depression in 65 percent of cases, social phobia in 34 percent of cases, and obsessive-compulsive disorder in 26 percent of cases.

Etiology
Biological, social, and psychological factors are implicated in the causes of anorexia nervosa. Some evidence points tohigher concordance rates in monozygotic twins than in dizygotic twins. Sisters of patients with anorexia nervosa are likely to be afflicted, but this association may reflect social influences more than genetic factors. Major mood disorders are more common in family members than in the general population. Neurochemically, diminished norepinephrine turnover and activity are suggested by reduced...