Eating Disorders Anorexia Diagnosis

Diagnosing anorexia nervosa is a complex process, made more difficult by the anorexic’s refusal to accept that she has a problem. To the anorexic, the need for weight loss is normal, so only rarely will an anorexic seek medical help. Anorexia nervosa usually only comes to a doctor’s attention when an anorexic seeks help for other medical disorders.

In some cases, the diagnosis of anorexia nervosa begins when concerned family members insist the anorexic seek medical help. Often the family has only become concerned after severe weight loss, making anorexia easier to diagnose, but more difficult to treat.

The Anorexic’s Medical History

A complete medical and psychological history will be gathered if anorexia is suspected. This will include details such as previous weight, extent of weight loss, physical symptoms, dieting history, binge eating, exercise levels, and family or relationship problems.

The examination will attempt to determine the anorexic’s perception of body image. Anorexics may not give accurate answers about weight loss, or attempt to deny the possibility of eating disorders. Interviewing family members may provide more realistic answers.

In addition to a medical history, a complete physical examination is required. The physical exam’s results will reveal complications of weight loss, starvation, and purging behavior, if present. Blood tests will usually be part of the physical examination, and electrocardiogram tests will be performed if there is reason to believe the heart has been affected.

The DSM-IV and Eating Disorders

For an anorexia diagnosis the patient’s symptoms must conform to the guidelines set out in the DSM-IV (the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders IV). Anorexia is considered to be present if the following four criteria are met:

  • Weight Loss: An anorexic will have a weight loss of at least fifteen percent of his or her normal body weight based on age and height. In other words, an anorexic’s body weight is less than 85 percent of what medical authorities would consider a minimum normal weight.
  • Fear of Weight Gain: An anorexic will display an intense fear of gaining weight, and worry incessantly about becoming fat. This fear persists even after severe weight loss.
  • Distorted Body Image: An anorexic’s image of the ideal body is profoundly disturbed. Even after severe weight loss, the anorexic will see herself as “fat.” Body image abnormally influences an anorexic’s self-worth, and has a profound effect on self-esteem. The distorted body image typical to anorexia nervosa leaves the anorexic unable to realistically evaluate weight loss. As such, the anorexic will often deny the seriousness of weight loss, even in the face of starvation.
  • Amenorrhea: Amenorrhea, or cessation of the menstrual cycle, must be present for an anorexia diagnosis in women. Amenorrhea is defined as a cessation of menses for at least three menstrual cycles. Amenorrhea is an important factor in anorexia nervosa diagnosis. An inadequate diet and malnutrition cause a drop in blood-borne sex hormones, resulting in the cessation of menstruation. Long-term amenorrhea causes hormone imbalances that increase the risk of osteoporosis in female anorexics.

Anorexia Nervosa Types

In addition to providing guidelines for the diagnosis of anorexia nervosa, the DSM-IV also divides the eating disorder into two distinct types, restricting and binge eating/purging. The two types are not separate eating disorders; instead, they classify anorexia by the methods used to achieve weight loss.

  • Restricting Type Anorexia Nervosa: In restricting type anorexia nervosa, weight loss is achieved by severe caloric restrictions and excessive exercise. During the current episode of anorexia, the anorexic must not have engaged in regular binge and purge behavior. Exercise is defined as excessive if the level of exercise interferes with daily activities. A restricting type anorexic will continue to exercise intensely despite injuries or exhaustion.
  • Binge and Purge Type Anorexia Nervosa: Binge and purge type anorexia resembles restricting-type anorexia, but also includes periods of binge eating followed by purging behavior to avoid weight gain. The two eating disorders are thought to stem from the same cause. Bulimia nervosa can develop into anorexia, and some recovered anorexics have developed bulimia. Binge and purge type anorexia resembles restricting-type anorexia, but also includes periods of binge eating followed purging behavior to avoid weight gain. Purging behavior includes self-induced vomiting, laxative abuse, and the use of diuretics and enemas.

Ruling Out Other Eating Disorders and Conditions that Mimic Anorexia

A number of eating disorders, medical conditions, and psychological disorders can mimic symptoms of anorexia nervosa, so it is essential that these disorders be ruled out before a firm diagnosis is made. Gastrointestinal disorders, brain tumors, AIDS and hormone imbalances may all mimic anorexia nervosa symptoms.

Clinical depression can suppress the appetite and lead to significant weight loss. This differs from anorexia nervosa, where appetite is normal in spite of weight loss. Depressed patients generally lack the fear of weight gain and unrealistic body image associated with anorexia nervosa. However depression often exists alongside anorexia and other eating disorders, and this must be kept in mind during diagnosis.

Schizophrenia occasionally mimics anorexia. A patient’s delusions make them believe their food is poisoned, for instance, leading to food avoidance and weight loss. However, schizophrenics rarely worry about calorie counts and weight loss.

Among eating disorders, bulimia nervosa is most likely to be confused with anorexia, especially if the anorexic displays symptoms of binge and purge behavior. Bulimics and anorexics are both overly concerned with body image and weight loss. However, the two eating disorders vary in effects: While anorexia results in excessive weight loss, bulimics are generally of normal weight, or slightly overweight.

After an Anorexia Diagnosis is Made

An anorexia diagnosis is difficult for families to deal with, and extremely difficult for the anorexic to accept. Counseling, nutritional therapy, and other anorexia treatments can be effective, but require an intense effort on the part of the anorexic to change her or his perceptions of body weight and and need to controlweight loss.


American Psychiatric Association. Diagnostic criteria for 307.1: Anorexia nervosa. Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. American Psychiatric Association, Washington, DC, 1994.

American Psychiatric Association. III. Disease definition, epidemiology, and natural history. Practice Guideline for the Treatment of Patients With Eating Disorders, 2nd Edition. American Psychiatric Association, Washington, DC, 2000.

Beers, M.H.