**Abstract**

Anorexia nervosa is characterized as having a significantly low body weight because of restricting energy intake or compensating to an excessive rate intentionally in order to attain or maintain an unrealistically thin ideal weight. Patients suffer multiple comorbid medical and psychiatric problems; moreover, deficits in treatment motivation are commonly seen, which causes a high rate of dropout from treatment programs. Thus, recent studies have focused on the etiology in order to develop efficient treatment options, as this can become a life-threatening problem. Prevention programs are also gaining attention, since full recovery can take a significant time and resources nevertheless may not be available for all cases. In this chapter, a brief history and basic diagnostic criteria of anorexia nervosa will be summarized. A review of comorbid psychiatric and medical conditions will be addressed. Prominent theories regarding its etiology and treatment options will be discussed in terms of a biopsychosocial approach. Finally, prevention studies will be highlighted.

**Keywords:** eating disorders, anorexia nervosa, body image, body dissatisfaction, compensatory behaviors, weight management strategies, dieting
