Medically reviewed on August 25, 2017
What Is It?
Anorexia nervosa is an eating disorder that affects about 1 in 100-200 girls or women in the United States. A person with this disorder limits eating and by definition weighs at least 15% less than his or her ideal weight.
At least 90% of cases are in women and the disorder usually begins in adolescence. The weight loss may delay the onset of menstruation or stop it once it has started, Anorexia nervosa rarely occurs before puberty or after age 40. And, although relatively rare, it can occur in men.
A person with this disorder fears being overweight. She may be completely convinced that she weighs too much despite what the scale shows or what other people say. To achieve or maintain leanness, she may exercise obsessively or use laxatives.
Because a super-restrictive diet requires exquisite control, she may become extremely careful, inhibited and controlled in other areas of life as well. For example, she may retreat from social contacts or may perform ritual behaviors.
The term "anorexia" literally means having a lack of appetite. But this is misleading because people with the disorder usually have a strong appetite or actively suppress a craving for food.
They diet to the point of starvation. And they may even experience pride stemming from the strength implied by such self-denial. The disorder is defined not by whether a person feels hunger but by how much weight he or she has lost.
Although anorexia nervosa appears in many cultures, it is most often diagnosed in industrialized societies, where thinness is often equated with attractiveness.
Many people have anorexia nervosa symptoms without having the full disorder. These symptoms can cause significant distress, particularly in adolescence, where girls and boys may strive for an idealized and unrealistic body image.
The cause of anorexia nervosa is not clear. It is likely a combination of inherited (genetic) vulnerability and environmental factors. Based on decades of research, experts see the disorder as having many elements:
Genetic. Anorexia nervosa tends to cluster among biological relatives. Sisters of patients with anorexia nervosa have a 6% risk of having the illness themselves. More distant relations have a risk up to 4%.
A variant of depression or anxiety. Anorexia, depression, anxiety and obsessive-compulsive disorder tend to run in families, and many people with anorexia nervosa have symptoms of depression or obsessive-compulsive disorder.
Associated with personality traits. People with anorexia nervosa are often given to compulsiveness and perfectionism. The eating may be an extension of, or a strong expression of, those traits.
Triggered by fears about becoming an adult. One fear may be related to new sexual feelings and activities that begin in adolescence. Sometimes the illness is triggered by a life event linked to normal development, such as moving away from home.
A response to environmental pressures. Cultural influences, including images from television and film and pressure from peers, leave the impression that thin is best. In some professions (for example, ballet dancing or modeling), thinness is highly prized, putting participants at risk. But culture is only part of the story. The illness has been known to have occurred hundreds of years ago, even at times when social pressures and conceptions of ideal body image were quite different.
A way to cope with difficult family relationships. Family difficulties can provoke the illness, but their importance may have been overemphasized in the past. Sometimes family problems develop after the disease has started, because a person with anorexia nervosa may test the patience of those she lives with. People with the disorder describe a feeling of power and control over others through their dieting.
In advanced stages of the illness, the restrictive dieting is hard to reverse. At that point, hunger may disappear completely and the pursuit of thinness becomes a way of life.
Starvation causes medical complications of its own, such as thyroid problems, anemia and joint pains. Extreme dieting can lead to death in the most severe cases, most commonly because of an irregular heartbeat caused by an imbalance of the salts in the bloodstream.
There are two subtypes of anorexia nervosa, a restricting type and a binge-eating/purging type. A person with the restricting type of anorexia diets, fasts and exercises. People with the binge-eating/purging type eat large quantities of food, then vomit. Many people go back and forth between these two patterns.
Symptoms of anorexia nervosa include:
Significant weight loss (more than 15% of ideal body weight)
Extreme dieting, including skipping meals or extended fasting
Obsessions about food and fears about eating in public
Use of laxatives
Binging and purging
Distorted self-image; feeling fat despite being thin
Self-esteem that depends on weight and appearance
Amenorrhea (stopping of menstrual periods or a delay of starting menstruation in young teens)
Skin dryness or flakiness
Brittle nails and hair
Swelling in feet and ankles
Intolerance to cold
Hypothermia (low body temperature)
A mental health professional, such as a psychiatrist, psychologist or social worker, can diagnose anorexia nervosa based on the history reported by the patient and the family. The person with anorexia may not report symptoms reliably, so reports from family members may be necessary to make a diagnosis. Often, a pediatrician or primary care physician is the first to make the diagnosis.
One special problem with this diagnosis is that individuals with the disorder often deny the problem and are reluctant to participate in an evaluation.
The health care professional will ask about the person's attitudes toward weight, food and body image, and he or she will check for lower than normal body weight and the physical signs of the illness, which include:
Low blood pressure
Enlarged salivary glands
Lanugo, a very fine type of body hair
The stopping of periods in a woman
Dental problems, because stomach acids can damage teeth if the person purges regularly
Some clinicians find it helpful to use screening tests. Examples are the Eating Disorders Inventory and the Eating Aptitudes Test.
As part of the evaluation, the clinician may explore whether the person has other problems that need treatment, such as a mood or anxiety disorder, obsessive-compulsive disorder, a personality disorder or substance abuse. It is common for people with anorexia nervosa to have symptoms of depression, including low mood, social withdrawal, irritability, poor sleep and diminished interest in sex. People with the binging/purging type of anorexia nervosa are more likely to have mood ups and downs, have problems with impulse control, and abuse alcohol and drugs.
Medical evaluation includes blood work to investigate whether poor nutrition has caused anemia (low red blood cell count), altered liver and kidney function, and abnormal levels of blood chemicals, such as low potassium.
The doctor may find:
Abnormal levels of chemicals in the blood serum
Changes in kidney and liver function
Changes in thyroid hormone, estrogen, and (in males) testosterone levels
Changes in the electrocardiogram (ECG)
Changes in bone mass
A doctor also needs to make sure there are no other medical problems that might be causing weight loss, such as inflammatory bowel disease, cancer or hormonal problems. People with those illnesses, however, do not usually have a problem with their body image.
Duration varies. Some people with anorexia nervosa have a single, relatively brief episode after experiencing an isolated stressful event. For others, the problem becomes chronic (long-lasting) and the person's condition gradually deteriorates.
Many people start by restricting food, then later binge and purge. Recent research has shown that the majority of cases go away by late adolescence. But a significant number of people do have continuing problems with diet and body image into adulthood, even though the severity of the symptoms is likely to be less.
There is no known way to prevent anorexia nervosa. It's helpful to detect the problem as early as possible, because early treatment can shorten the course of the illness.
Clinicians aim first to evaluate whether or not a person with anorexia nervosa is in medical danger as a result of food restriction. A general goal is to help the person achieve a minimum healthy weight. But there is not one most recommended way to accomplish this goal.
A priority is to correct any problems with body fluids and salts. Doctors evaluate the person's heart, liver and kidney functioning and provide necessary medical support. Hospitalization may be necessary in the most severe cases (for example, when weight loss is more than 20-25% of body weight), but most treatment is done in an outpatient setting.
Treatment often requires coordinating help from a number of professionals, especially in the most serious cases. Comprehensive eating disorders programs are efficient because they bring all the treatment elements together.
One major task is helping the person with anorexia nervosa recognize the illness and participate in treatment. Education is key, with an emphasis on addressing the distorted beliefs about body image that are central to the disorder. But it should be noted that patients with anorexia nervosa are – in many ways – already experts in their illness. Therefore, the people providing treatment have to try not to behave in a way that could be perceived as patronizing or scolding.
Anorexia nervosa is best treated with a combination of psychotherapy, support, education, medication, and medical and nutritional supervision.
Although a number of specialized psychotherapy approaches have been studied, there is some evidence that supportive psychotherapy and sympathetic clinical management are just as – if not more – helpful. Elements include education, care and support. Praise, reassurance and advice can help sustain a positive therapeutic relationship that encourages adherence to treatment.
Behavior treatments that solely provide rewards and punishments to change eating behavior are probably not effective if they don't also deal with the patient's distorted thinking. They may help in the short run, but patients can easily learn how to comply with the program to gain discharge (i.e., "eat their way out of the hospital"). Then, since they have not given up their distorted body image and beliefs about food, they soon resume abnormal eating.
Health care professionals try to define the problem in a way the person can accept, then work with the person toward common goals.
No single psychotherapy approach has proven to be better than any other. Therefore, once the person acknowledges the problem, a variety of therapy techniques may be tried.
A nutritionist can plan a healthy eating program that promotes slow weight gain.
Cognitive therapy encourages the person to recognize flawed thoughts about body image, food and dieting, and helps to control anxiety about eating.
Family therapy may be important, both to support and educate family members and to examine negative interactions in the family. For example, family members can be taught to avoid unproductive power struggles about food. In families where there is a great deal of open conflict, educational programs designed for parents may be more useful than therapy meetings that include the patient.
Later, when symptoms are under better control, the person with anorexia nervosa may want to understand the meaning of the symptoms, including how they may have affected important relationships, limited emotional growth and altered self-concept. It may also be possible to look at what problems may have set off the eating disorder in the first place.
As with psychotherapy, there is no single medication that has been proven best for anorexia nervosa. Low weight also can make a person more susceptible to drug side effects.
Antidepressant medications can improve associated mood problems. But they usually do not hasten weight gain (unless depression is in part causing the weight loss).
No medication is known to make a person with this disorder want to eat or gain weight. Nonetheless, antidepressants and other medications may provide relief for people who have symptoms of depression, anxiety or obsessive-compulsive disorder. There is also some evidence that selective serotonin reuptake inhibitors like fluoxetine can help reduce relapse.
A person's thinking about food can become distorted enough that it is considered psychotic, and in those cases, treatment may include an antipsychotic medication. Some of the newer antipsychotic drugs, such as olanzapine (Zyprexa), have weight gain as a side effect. In this case, the side effect may be a benefit, but a person with anorexia nervosa may also not tolerate it.
When To Call a Professional
Contact a mental health professional, a pediatrician or a primary care physician if you have a question about food restriction, feelings of sadness or anxiety, or persistent problems with body image. A family member may be the first to notice such problems and should contact a health care professional on behalf of the person having trouble.
Severe weight loss or starvation can become a medical emergency so early treatment is desirable.
Many people have mild forms of anorexia nervosa and are open to treatment. These people will respond well, particularly when a variety of approaches are combined.
For people who have lost a great deal of weight and have medical complications, aggressive care can reverse a downward course. There is a significant risk of death for people who have been hospitalized for medical complications of anorexia nervosa, especially when they are very resistant to treatment. However, the majority of people with anorexia nervosa either improve significantly or have a full recovery.
People who have recovered from anorexia nervosa may need long-term support and treatment to prevent relapse.
Learn more about Anorexia Nervosa
Micromedex® Care Notes
Mayo Clinic Reference
National Association of Anorexia Nervosa and Associated Disorders
American Psychiatric Association
American Psychological Association
National Institute of Child Health and Human Development
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.