Anorexia nervosa

Anorexia Eating Disorder

What is Anorexia nervosa?

Anorexia nervosa is characterized by a refusal to maintain a minimally normal body weight (based on a person’s age and body size), a distorted body image, an intense fear of gaining weight and amenorrhea (absence of menstruation) in females who have had their first menstrual period. For instance, individuals with anorexia nervosa often believe they are fat despite being extremely underweight.

Anorexia nervosa differs from another eating disorder called bulimia nervosa. Individuals with bulimia nervosa usually maintain a normal body weight or are overweight. To be diagnosed with anorexia nervosa, a person must weigh more than 15 percent below the normal range for their age and body size and exhibit a distorted body image.

Eating (especially a healthy, well-balanced diet) is necessary for normal functioning of all organ systems. Disordered eating habits (e.g., skipping meals) or prolonged dieting (e.g., calorie restriction) may deplete the body of important nutrients. In some cases, such habits may become chronic and may lead to the development of an eating disorder, such as anorexia nervosa.

Anorexia nervosa can be particularly dangerous because it puts a person at risk for malnutrition. Individuals with anorexia nervosa tend to associate their self-worth or self-esteem with the way their bodies look and attempt to control their weight through harmful methods, including starvation and purging.

People with anorexia nervosa typically achieve weight loss by drastically reducing their food intake. Patients often begin by eliminating high-calorie foods from their diet, but most usually end up with a very restricted diet that is sometimes limited to only a few foods.

Additional methods for weight loss include purging methods, such as self-induced vomiting or misusing laxatives and/or diuretics, in addition to increased or excessive exercise (anorexia athletica). Individuals with anorexia nervosa may also rely on diet pills, recreational drugs (e.g., amphetamines, cocaine) and caffeine (e.g., coffee, caffeinated diet drinks) to suppress hunger and boost energy. Prolonged use of these agents may result in tolerance and withdrawal symptoms, which can be exacerbated in low-weight people who use these substances in excess.

Patients with anorexia nervosa often exhibit other types of mental disorders including depression (due in part to being severely underweight) and anxiety disorders, which may also become exacerbated by prolonged starvation. Obsessive-compulsive features, such as chronic calorie counting and hoarding food, are also prominent among people with anorexia nervosa. However, most individuals with anorexia nervosa are only preoccupied with thoughts of food and weight.

Anorexia nervosa is more prevalent in females than males, especially among adolescents and young adults. According to the U.S. Department of Health and Human Services, it ranks as the third most common chronic illness among adolescent girls in the nation.

Anorexia nervosa typically begins during adolescence or early adulthood. However, some reports indicate that its onset can occur during childhood, even before children reach puberty, or later in adulthood. It is more common in industrialized, economically developed nations.

Anorexia nervosa can have severe, life-threatening complications. Prolonged starvation can lead to malnutrition and damage of the vital organs, including the heart and brain. In addition, nutritional deprivation often results in the loss of bone mass (osteoporosis), which may result in brittle bones that break easily. Other complications from malnutrition include amenorrhea, anemia (low red blood cell count), infertility (inability to get pregnant), hair loss and a failure to grow in children or adolescents. In the case of patients who engage in prolonged self-induced vomiting, damage to the teeth, gums and upper gastrointestinal tract can occur. If left untreated, patients with anorexia nervosa may literally starve themselves to death. Limited food intake and purging can also lead to other health problems, such as injuries to the esophagus.

Often, people with anorexia nervosa are in denial and do not recognize or admit that there is a problem and as a result, may become extremely resistant to seeking medical treatment. In such cases, the intervention of family members, teachers or peers may be necessary to ensure that the individual exhibiting symptoms of anorexia nervosa receives proper medical attention.

Types and differences of anorexia nervosa

Anorexia nervosa is an eating disorder that is characterized by an obsession to be thin, relentless and harmful dietary habits (e.g., starvation, purging) and weight loss.

There are two types of anorexia nervosa:

Binge-eating/purging type

In this type of anorexia nervosa, patients regularly engage in binge eating and/or purging behaviors to control their weight. This is the most common type of anorexia nervosa. Often people with anorexia nervosa who binge eat also practice purging methods, including self-induced vomiting or misusing laxatives, diuretics or, rarely, enemas (injecting liquid into the intestines through the anus to empty the bowels). Sometimes, individuals with this type of anorexia nervosa do not binge eat, but regularly purge after consuming even small amounts of food.

It is important to note that this type of anorexia nervosa differs from another eating disorder called bulimia nervosa. Although individuals with bulimia nervosa also engage in purging behaviors, they usually maintain a normal body weight or are overweight. To be diagnosed with anorexia nervosa, a person must weigh more than 15 percent below the normal range for their age and body size and exhibit a distorted body image.

Restricting type

In this type of anorexia nervosa, patients do not engage in purging methods to accomplish weight loss. Rather, individuals with restricting anorexia nervosa attain weight loss mainly by dieting, fasting and/or excessive exercise (anorexia athletica).

Risk factors and causes of anorexia nervosa

The exact cause of anorexia nervosa is not thoroughly understood. Perhaps part of the explanation for its prevalence in economically developed nations may be the messages the media sends regarding ideal beauty and attractiveness. These messages often promote thinness as the female ideal. In order to be thin or slender, some people achieve and maintain a weight that may not always be healthy for their bodies. In some cases, it is possible to be slender and healthy at the same time. However, it becomes a serious health problem when people use detrimental methods (e.g., starvation) to achieve thinness.

Generally, a combination of various factors is believed to contribute to the development of anorexia nervosa. These include:


Females are more likely to develop anorexia nervosa than males. However, males may also develop this type of eating disorder. According to the U.S. National Institute of Mental Health (NIMH), about 5 to 15 percent of patients with anorexia nervosa or bulimia nervosa are male.


Even though anorexia nervosa may occur at any age, it is more common among teenagers and young adults (people in their 20s and early 30s).


Anorexia nervosa is more common among people with close family members with the eating disorder. Studies of twins also support this theory. However, it is not clear specifically how genetics plays a role. Researchers believe that genetics may contribute by creating a tendency toward perfectionism, sensitivity and perseverance, all traits associated with anorexia nervosa.

Emotional disorders

Often, people with anorexia nervosa have other types of psychological disorders, including depression, anxiety disorders (e.g., obsessive-compulsive disorder) and substance abuse. Generally, the presence of a pre-existing emotional disorder often reinforces the eating disorder and vice versa.

Certain personality traits

Individuals with anorexia nervosa often exhibit the following personality traits:

  • Low self-esteem and feelings of inadequacy or lack of control in life.
  • Perfectionism. Wanting to look and be perfect is often equated with thinness.
  • Lack of communication skills. Patients with anorexia nervosa often have difficulty communicating negative emotions and/or resolving conflict.


Sometimes, anorexia nervosa may be triggered by stressful situations and/or traumatic events, including a history of abuse (e.g., physical, sexual), dysfunctional family, divorce, death of a family member or friend or starting a new school or job.

Family and social influences

Individuals whose parents, siblings or other close family members and friends are overly critical of their weight, appearance and/or eating habits may be at increased risk of engaging in harmful methods of weight control (e.g., starvation, purging), which can put them at risk of developing anorexia nervosa.

Competitive sports and performance arts

While competitive sports or artistic activities (e.g., ballet, gymnastics, figure skating, wrestling, acting) do not directly cause anorexia, people, especially females, who participate in these activities may be at increased risk of using harmful methods of weight control (e.g., abusing diet pills) due to the strict weight requirements of certain sports or performance arts. Prolonged use of such methods may put individuals at risk of developing anorexia nervosa.

In addition, pro-eating disorder Web sites, which encourage eating disorders including anorexia nervosa and bulimia nervosa by offering tips and support, have proliferated on the Internet in recent years. These sites are especially harmful to vulnerable teenagers who view anorexia nervosa or bulimia nervosa as a “lifestyle choice” rather than a serious illness that may result in death. In fact, some experts believe that these sites may interfere with treatment and cause relapse of the eating disorder in many patients.

Signs and symptoms of anorexia nervosa

Excessive weight loss – especially if a person reaches a weight that is less than 85 percent of the ideal weight for their age and height – is the initial sign of anorexia nervosa. In addition, individuals with anorexia nervosa may express an intense fear of gaining weight or exhibit a negative body image (e.g., belief that they are fat despite being extremely thin). They may also exhibit anxious or ritualistic behaviors during mealtimes (e.g., making excuses to avoid eating, playing with food on plate) and/or exercise excessively or compulsively (anorexia athletica). Some individuals with anorexia nervosa also dress in layers or baggy clothes to hide their weight loss.

Other signs and symptoms of anorexia nervosa may include:

  • Social withdrawal
  • Depression
  • Insomnia
  • Chronic fatigue, lightheadedness and/or concentration problems
  • Headache
  • Anemia (decreased red blood cells)
  • Absence of menstruation (amenorrhea) in females of menstruating age for at least three consecutive menstrual cycles
  • Breast atrophy (loss of breast mass in females)
  • Muscle atrophy (deterioration of muscles)
  • Constipation
  • Dry skin, including brittle hair and nails
  • Hair loss
  • Tooth decay and gum disease (due to prolonged self-induced vomiting)
  • Cold hands or feet; loss of body temperature (hypothermia)
  • Irregular heart rate (bradycardia)
  • Low blood pressure (hypotension)
  • Swelling of the parotid and submandibular (salivary) glands
  • Development of lanugo (fine body hair) on the trunk (in advanced stage)

Diagnosis methods for anorexia nervosa

Physicians may diagnose anorexia nervosa based on the patient’s symptoms and eating habits. During an initial consultation, a physician will record the patient’s weight and perform a thorough physical examination including:

  • Checking vital signs, such as heart rate and blood pressure
  • Evaluation of patient’s skin, abdomen and teeth
  • Neurological examination to evaluate other potential causes of weight loss and/or vomiting, such as liver disease or a brain tumor
A physician will also compile a comprehensive medical history including any family history of physical and mental disorders (e.g., depression, obsessive-compulsive disorder) as well as inquire into the patient’s history of dieting and/or eating patterns. Some of the questions a physician may ask include:
  • Has the patient recently lost more than 14 pounds (6.35 kg) in a three-month period?
  • Does the patient believe they are fat when others say they are too thin?
  • Does food dominate the patient’s life?
  • Does the patient induce sickness (vomiting) because they fear gaining weight?
  • Does weight affect the patient’s self-image?
In addition, a physician may order diagnostic tests to identify any signs of complications of anorexia nervosa including malnutrition, anemia (reduced red blood cell count), reduced heart rhythms (bradycardia), digestive problems (e.g., constipation), bone density loss or changes in the menstrual cycle.

Additional diagnostic tests may include:

Blood tests

Laboratory analyses – including a complete blood count (CBC) – of blood samples to measure levels of hormones, enzymes, proteins, electrolytes, vitamins and other substances to assess the function of various organ systems including the liver, kidney, thyroid and pituitary glands as well as the ovaries (female reproductive glands).


Chemical examination of a urine sample to screen for urinary tract infection, kidney disease and diseases of other organs that result in the appearance of abnormal metabolites (break-down products) in the urine.

Electrocardiogram (EKG)

This test measures the pattern of electrical impulses generated by the heart. During the procedure, electrodes (devices that detect electrical impulses) are attached to the patient’s chest. The electrical impulses are then recorded on a graph. In patients with anorexia nervosa, an EKG can help detect irregular heartbeats (e.g., bradycardia) and identify the presence of any damage to the heart.

Imaging tests (e.g., x-ray, MRI, CAT scan)

These tests are useful in detecting the presence of any damage in the chest, digestive tract, organs and/or brain caused by anorexia nervosa. For example, a chest x-ray may reveal whether anorexia nervosa has damaged the heart muscles by reducing the size of the heart.

Bone density test

During this test, a physician may use a device called a sonometer to pass painless sound waves through the bones to measure the density of the bones and check for signs of bone mass loss (osteoporosis).

When anorexia nervosa is diagnosed, a physician may refer the patient for supplementary treatment with a mental and/or behavioral health specialist (typically a psychiatrist for a psychiatric evaluation), nutritionist (a licensed nutrition expert) and/or dentist for the treatment of dental complications, such as tooth and gum decay, which may occur with regular self-induced vomiting (binge-eating/purging-type anorexia nervosa).

Treatment options for anorexia nervosa

The sooner an individual with anorexia nervosa is diagnosed and begins treatment, the better the outcome is likely to be. Due to its complexity, anorexia nervosa usually requires a comprehensive treatment plan, including medical care and monitoring of health complications (e.g., malnutrition), psychological evaluation and dietary counseling.

In severe cases of malnutrition, immediate hospitalization of the patient may be necessary to rehydrate (restore loss of water) and restore electrolyte imbalance through intravenous (into a vein) feeding.

Patients with dental problems (e.g., tooth and gum decay) resulting from binge eating/purging type anorexia nervosa may be referred to the care of a dentist for treatment.

Anorexia nervosa typically requires a multi-disciplinary approach for rehabilitation that may include:

Nutritional counseling

Regular consultation with a nutritionist (licensed nutrition specialist) or registered dietitian is important for patients with anorexia nervosa. Nutrition experts may help patients gain a fundamental understanding of adequate nutrition, including the importance of a healthy, well-balanced diet. These specialists also conduct dietary counseling, which can help patients change the nature of their eating behavior. In the case of anorexia nervosa, a nutritionist may initially place the patient on an eating plan for gradual weight gain. This is done to prevent any harm to the body, especially the heart, from a rapid increase in weight.


Psychotherapy (e.g., cognitive behavioral therapy [CBT], family therapy). These types of mental health therapy will address and help treat psychological disturbances including distortion of body image, abuse issues, mental illnesses (e.g., depression, anxiety disorders), low self-esteem and interpersonal conflicts associated with anorexia nervosa.

Drug therapy

Drug therapy (psychotropic medications, such as antidepressants).Antidepressants, such as the selective serotonin reuptake inhibitors (SSRIs), have been found helpful in treating anorexia nervosa that co-exists with other types of emotional disorders, especially depression and anxiety disorders. Psychotropic medications may also help prevent relapse of the eating disorder. The U.S. Food and Drug Administration (FDA) issued an advisory to healthcare providers to monitor children and adolescents being treated with antidepressants for increased suicidal thinking and behaviors.

Since psychotherapy (e.g., CBT) appears more effective than medication for anorexia nervosa, use of medication in people with anorexia nervosa is usually offered as an adjunctive treatment to, and not a replacement for, psychotherapy. Some medication treatment may pose additional risks among this population because of their low body weight, abnormal heart rhythm and electrolyte imbalance.

Patients with anorexia nervosa are urged to get regular check-ups with their physician to monitor their overall health and treat any complications, such as bradycardia (reduced heart beat). Sometimes, residential care that involves the patient remaining in a facility that specializes in treating anorexia nervosa may be necessary, especially in the case of chronic relapses or when patients have not been able to reach a significant degree of medical and psychological stability from their initial treatment plan.

Sometimes people with anorexia nervosa are in denial and may refuse to recognize that there is a problem. Oftentimes, they may resist getting and staying in treatment. Family members and other individuals close to the patient are urged to ensure that the person suspected of having anorexia nervosa receives needed care and rehabilitation. For some patients, medical treatment may be long term.


Prevention methods for anorexia nervosa

Although anorexia nervosa cannot always be prevented, it can be more effectively managed by taking steps that can reduce chances of a relapse including:

  • Attending regular follow-up consultations with a primary care physician, psychotherapist and nutritionist to monitor the eating disorder
  • Eating healthy, well-balanced meals
  • Following a regular schedule of meals
  • Taking vitamin and mineral supplements
  • Exercising regularly as recommended by the physician
  • Getting proper rest and sleep
  • Engaging in activities that boost self-esteem, such as learning a new skill or hobby or joining a local social group
  • Learning realistic expectations regarding body and weight. (For example, not accepting some media portrayals of ideal body image.)
Family members and close peers of people with eating disorders can be a source of help and support by encouraging open communication and healthy eating and dieting habits. People with anorexia nervosa may also benefit greatly from participating in support groups to prevent relapse as well as help cope with their condition. Physicians and psychotherapists can provide patients with information regarding support groups for people with anorexia nervosa.

Questions for your doctor on anorexia nervosa

Preparing questions in advance can help patients and their families or friends have more meaningful discussions with their physicians regarding treatment options for the eating disorder. Patients and their families or friends may find the following questions about anorexia nervosa helpful:

  • What is your experience and how long have you been treating patients with anorexia nervosa?
  • Is there a cause or trigger for anorexia nervosa?
  • How is anorexia nervosa diagnosed?
  • Can I die from anorexia nervosa?
  • What type of treatment will I need?
  • How long will the treatment process take?
  • Will I need to take medications for anorexia nervosa?
  • Should I receive therapy? What type of therapy would be best for me?
  • Are there support groups for people with anorexia nervosa in our community?
  • I have a family member or friend with anorexia nervosa. What are the best ways to help them?