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Anorexia nervosa: Symptoms, Causes, Diagnostic tests and Treatments

Anorexia nervosa is one of the representative eating disorders, characterized by persistent behavior to lose weight, weight loss, inappropriate obsession with food and weight, bizarre food handling behavior, strong fear of gaining weight, and amenorrhea.


Typically, symptoms of anorexia nervosa begin between the ages of 10 and 30.

Patients with anorexia nervosa have a strong fear of weight gain and obesity, and are indifferent or resistant to treatment.

Patients with anorexia nervosa are secretive about inappropriate dietary behaviors associated with weight loss and avoid eating with family members or in public places.

The term’anorexia’ actually has an inadequate side, as the actual loss of appetite is not common until the end of the disease. Sometimes binge eating is accompanied, usually in secret and often at night. After binge eating, it is common to induce vomiting of the food consumed by itself or to remove it using a laxative.

Patients with anorexia nervosa frequently abuse laxatives and diuretics and practice excessive exercise habitually.

Patients with anorexia nervosa often exhibit inappropriate food-related behavior, such as hiding food throughout the house.

Severe weight loss can lead to various medical problems such as hypothermia, amenorrhea, edema, and low blood pressure.


Biological, social and psychological factors are presumed to be the cause of anorexia nervosa.

There are reports of biological studies such as abnormalities in the hypothalamus-pituitary axis or structural and functional abnormalities in the brain.

Social factors are related to social issues about movement and slimness. Psychological and psychodynamic factors include psychological independence from mothers.

Diagnosis methods

According to the diagnostic criteria of the American Psychiatric Association’s Manual of Diagnostic Statistics for Mental Disorders (DSM-5), anorexia nervosa is diagnosed when all of the following symptoms are present.1

  1. Restriction of energy intake relative to requirements, leading to a significant low body weight in the context of the age, sex, developmental trajectory, and physical health (less than minimally normal/expected2).
  2. Intense fear of gaining weight or becoming fat or persistent behavior that interferes with weight gain.
  3. Disturbed by oneโ€™s body weight or shape, self-worth influenced by body weight or shape, or persistent lack of recognition of seriousness of low bodyweight.

After diagnosis of anorexia nervosa, the types are subdivided into Restricting type and Binge-eating/purging type as follows.

  1. Restricting type: Regular binge eating or not using laxatives. In other words, there is no self-induced vomiting or abuse of laxatives, diuretics, and enema. Refusing to eat only.
  2. Binge-eating/purging type: Regular binge-eating or using laxatives. That is, self-induced vomiting or abuse of laxatives, diuretics, and enema.

Test methods

First of all, tests and differential diagnosis for other diseases that can cause weight loss, such as brain tumors or cancer, must be performed.

Differentiation from other neuropsychiatric diseases should be performed through psychiatric consultation and examination, and an accurate evaluation of the current overall health status should be made through medical examination.


Since it is often an emergency situation accompanied by serious medical problems as well as psychiatric problems, a comprehensive treatment plan including hospitalization should be established. It is effective to conduct individual and family therapy at the same time. In addition to psychotherapeutic approaches such as cognitive behavioral therapy, appropriate medications should be considered.

In general, if the patient is under 20% of the expected weight by height, or if other medical problems are serious, immediate hospitalization should be actively considered.

Progress and complications

The course of anorexia nervosa ranges from spontaneous recovery to death from serious complications. Short-term treatment outcomes are not bad. However, even after regaining enough weight, it is common for inappropriate perceptions of food and weight to persist. As a result, there are many cases of interpersonal disorders and depression.

It cannot be said that the overall prognosis is good. According to the research results, the mortality rate ranges from 5 to 18%.

According to a 10-year follow-up study conducted in the United States, one-quarter of all patients recovered to normal, and another half showed significant improvement and performed well in daily life. The remaining one-quarter patient group had a mortality rate of 7%, chronically underweight and unable to adapt well to daily life.

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