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Anorexia Nervosa: Symptoms, Causes, and Treatments

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Anorexia nervosa is a life-threatening eating disorder. It is defined as self-starvation in order to maintain an abnormally low body weight. Low body weight is described as weighing less than the minimum that is considered normal for the person’s age, sex, stage of growth and development, and physical health. Individuals with anorexia nervosa have an intense fear of gaining weight or becoming fat and have a distorted self-image of their body weight and shape. Extreme weight loss in people with anorexia nervosa can lead to dangerous health problems and even death.

Anorexia Nervosa

Who gets anorexia nervosa?

Anorexia nervosa can occur in people of any age, sex, race, gender, ethnicity, economic status, as well as individuals of all body weights, shapes and sizes. Anorexia nervosa is most commonly seen in adolescents and young adult females, although it also occurs in males and is increasing in numbers in children and older adults.

What are the health harms of anorexia nervosa?

Not getting enough nutrients (malnutrition) and starvation affects nearly every system of the body.

  • Effects on the heart. Slow heart rate (bradycardia), low blood pressure (hypotension) and orthostatic hypotension are common effects of starvation. These complications increase the risk of ventricular arrhythmia and sudden cardiac death. The heart itself can lose some of its muscle mass, which can lead to mitral valve prolapse.
  • Effects on the brain. Starvation affects the brain’s structure – including decreased brain tissue and brain activity and function. Functions impaired include decision making, ability to concentrate/focus, memory issues, emotional control, appetite regulation, mood and reward pathways.
  • Effects on the digestive tract. Starvation can cause abdominal discomfort and pain, bloating, constipation, feelings of being full, as well as lead to fatty liver disease (steatosis).
  • Effects on the body’s hormones. Starvation can cause missed menstrual periods (amenorrhea) and reduced levels of female hormones, low testosterone levels, delayed puberty and physical growth, underactive thyroid (hypothyroidism), euthyroid sick syndrome, and in older individuals, increased the risk of weak bones (osteopenia), bone loss (osteoporosis) and stress fractures.
  • Effects on the body from vomiting (purging). Exposure to stomach acid can wear down the enamel on teeth and enlarge the salivary glands. Loss of water and electrolyte/acid-base imbalances can cause a loss of potassium and lead to rhabdomyolysis (damaged skeletal muscle) and kidney damage.

Many of these complications can improve and be reversed as weight is regained. However, if anorexia nervosa has been ongoing for years, bone loss, physical growth, and structural brain changes may not fully recover.

What are the symptoms and behaviors of people with anorexia nervosa?

Physical signs and symptoms include:

  • Significant weight loss over several weeks or months
  • Unexplained change in growth curve or body mass index (in still growing child/adolescent)
  • Feeling tired
  • Slow or irregular heart beat
  • Sleep problems
  • Poor concentration/focus
  • Memory loss
  • Feeling cold all the time
  • Dizziness
  • Fainting
  • Absent or irregular menstrual periods
  • Chest pain, heart palpitations
  • Low blood pressure (hypotension)
  • Shortness of breath
  • Swelling (edema)
  • Swelling in the neck area
  • Dental cavities, erosion of tooth enamel
  • Bloating, abdominal pain or discomfort
  • Blood in vomit
  • Heartburn (gastroesophageal reflux)
  • Constipation
  • Hemorrhoids
  • Muscle weakness, loss of muscle mass
  • Dry skin, brittle nails, hair loss/thinning hair, growth of fine hair on the body (lanugo)
  • Poor wound healing
  • Bluish or purple coloring of the hands and feet

Emotional and behavioral symptoms include:

  • Binge eating or purging behavior
  • Continuing to diet even when thin or when weight is very low
  • Having an unusual interest in food, calories, fat grams and dieting
  • Sudden change in eating behavior – becoming a vegetarian/vegan; interest in certain food types or certain food groups, or eliminating certain food types or food groups
  • Intense fear of gaining weight
  • Strange eating habits or routines, such as eating in secret, eating foods in a certain order, rearranging foods on a plate
  • Feeling fat, even if underweight
  • Inability to realistically assess one’s own body weight
  • Striving for perfection and being very self-critical
  • Undue influence of body weight or shape on self-esteem
  • Depression, anxiety, or irritability
  • Obsessive/compulsive symptoms and behaviors
  • Infrequent or irregular menstrual periods in females
  • Laxative, diuretic, diet pill or appetite suppressants, or enema use
  • Purposely not taking insulin (in people who have diabetes) to lose weight
  • Frequent illness
  • Wearing loose clothing to hide weight loss
  • Compulsive exercising or extreme physical training
  • Feeling worthless or hopeless
  • Withdrawal from friends and social events
  • Inability to describe one’s emotions
  • Doesn’t enjoy life; thoughts of self-harm or suicide

What causes anorexia nervosa?

The exact cause of anorexia nervosa is not known, but research suggests that a combination of certain personality traits, emotions and thinking patterns, as well as biological and environmental factors might be responsible.

People with anorexia nervosa may use food and eating/not eating as a way to gain a sense of control when other areas of their lives are very stressful or when they feel overwhelmed. Feelings of inadequacy, low self-esteem, anxiety, anger, or loneliness also might contribute to the development of the disorder. In addition, people with eating disorders might have troubled relationships or have a history of being teased about their size or weight. Pressure from peers and a society that equates thinness and physical appearance with beauty also can have an impact on the development of anorexia nervosa.

There is no single path to an eating disorder. For many, irregular eating behaviors (also called “disordered eating”) represents an inappropriate (doctors may say, “maladaptive”) coping strategy that becomes permanent over time. This pathway to disordered eating is true for some, but not all, who develop this set of illnesses.

Eating disorders also might have physical causes. Changes in hormones that control how the body and mind maintain mood, appetite, thinking, and memory might foster eating disorders. The fact that anorexia nervosa tends to run in families also suggests that a susceptibility to the disorder might be inherited.

How is anorexia nervosa diagnosed?

If symptoms are present, the doctor will begin an evaluation by performing a complete medical history and physical examination. Diet history will be taken – the individual will be asked about the quantity and variety of foods/food groups and thoughts about food. The doctor will ask about body image and weight loss history and measure weight and height and compare with age-based weight and growth charts. Binge and purging frequency and elimination habits (diet pills, laxatives, supplements) will be discussed. Current medications will also be reviewed. The doctor will also ask about menstrual history, exercise history and family history of eating disorders, substance abuse and psychological disorders (mood, depression, suicidal thoughts).

Although there are no laboratory tests to specifically diagnose anorexia nervosa, the doctor might use various diagnostic tests, including laboratory values (a blood test), to rule out physical illness as the cause of the weight loss, as well as to evaluate the severity of illness or the effects of the weight loss on the body’s organs. The doctor may order an electrocardiogram (ECG) to check for slow heart rate, chest pain, abnormal heart rhythm, or heart flutter.

To be diagnosed with anorexia nervosa, the doctor will determine if three criteria have been met:

  • Does the person weigh less than the minimum that is considered normal for their age, sex, stage of growth and development, and physical health?
  • Does the person have an intense fear of gaining weight or becoming fat or display ongoing behavior that interferes with weight gain even though the individual is at a significantly low weight?
  • Does the person show a disturbance in the way they view their body weight or shape; does their body weight or shape have a strong influence on their self-image; does the person lack recognition of the seriousness of their current low body weight.

How is anorexia nervosa treated?

The goals of treatment are to stabilize weight loss, begin nutrition rehabilitation to restore weight, eliminate binge eating/purging behaviors and other ritualistic eating patterns, treat emotional issues such as low self-esteem, correct distorted thinking patterns, and develop long-term behavioral changes.

Treatment options will vary depending on the individual’s needs. Treatment most often involves a combination of the following strategies:


This is a type of individual counseling that focuses on changing the thinking (cognitive therapy) and behavior (behavioral therapy) of a person with an eating disorder. Treatment includes practical techniques for developing healthy attitudes toward food and weight, as well as approaches for changing the way the person responds to difficult situations. There are several types of psychotherapy including:

  • Acceptance and Commitment Therapy. This therapy’s goal is to develop motivation to change actions rather than your thoughts and feelings.
  • Cognitive Behavioral Therapy (CBT). This therapy’s goal is to address distorted views and attitudes about weight, shape and appearance and practice behavioral modification (if “X” happens, I can do “Y” instead of “Z”).
  • Cognitive Remediation Therapy. This therapy uses reflection, and guided supervision to develop the capability of focusing on more than one thing at a time.
  • Dialectical Behavior Therapy (DBT), is CBT plus insight. In other words, this therapy helps the individual not just develop new skills to handle negative triggers, but also helps the person develop insight to recognize triggers or situations where a non-useful behavior might occur. Specific skills include building mindfulness, improving relationships through interpersonal effectiveness, managing emotions and tolerating stress.
  • Family-based Treatment (also called the Maudsley Method). This therapy involves family-based refeeding, which means putting the parents/family in charge of getting the appropriate nutritional intake consumed by the individual with the eating disorder. It is the most evidence-based method to physiologically restore health to an individual with anorexia nervosa who is under 18 years of age.
  • Interpersonal Psychotherapy. This therapy is aimed at resolving an interpersonal problem area. Improving relationships and communications, and resolving identified problems has been found to reduce eating disorder symptoms.
  • Psychodynamic Psychotherapy. This therapy involves looking at the root causes of anorexia nervosa – what are the patient’s true underlying needs and issues -- as the key to recovery.


The antipsychotic olanzapine (Zyprexa®) may be helpful for weight gain. Although there is no clear evidence that antidepressant medications can help individuals gain weight, some doctors may prescribe these drugs to help control anxiety and depression associated with an eating disorder.

Nutrition counseling

This strategy is designed to teach a healthy approach to food and weight, to help restore normal eating patterns, and to teach the importance of nutrition and a balanced diet.

Group and/or family therapy

Family support is very important to treatment success. It is important that family members understand the eating disorder and recognize its signs and symptoms. People with eating disorders might benefit from group therapy, where they can find support, and openly discuss their feelings and concerns with others who share common experiences and problems.


Treatment can take place outside the hospital or at an inpatient facility. To be considered for outpatient therapy, patients need to be medically and psychiatrically stable, have symptoms under control and not require daily medical monitoring.

The choice of residential care or hospitalization depends on how stable the patient is medically and from a mental health perspective, if the patient needs intensive medical care and/or daily assessment. Hospitalization might be needed to treat severe weight loss that has resulted in malnutrition and other serious mental or physical health complications, such as heart disorders, serious depression and suicidal thoughts or behaviors.

What are the complications of treating anorexia nervosa?

The most serious complication of treating anorexia is a condition called refeeding syndrome. This life-threatening condition can occur when a seriously malnourished person begins to receive nutrition again. Basically, the body cannot properly restart the metabolism process.

Patients experiencing refeeding syndrome can develop:

  • Whole body swelling (edema)
  • Heart and/or lung failure
  • Gastrointestinal problems
  • Extensive muscle weakness
  • Delirium
  • Death

Abnormal laboratory signs include low phosphate levels (hypophosphatemia), low blood sugar levels, (hypoglycemia), low potassium level (hypokalemia), low magnesium level (hypomagnesemia), and low sodium level (hyponatremia).

Patients who have one or more of the following risk factors for developing refeeding syndrome may need to be treated in the hospital:

  • Are severely malnourished (< 70 percent median BMI in adolescents; BMI < 15 in adults)
  • Have had little or no calorie intake for more than 10 days
  • Have a history of refeeding syndrome
  • Have lost a lot of weight in a very short period of time (> 10 to 15 percent of total body mass within 3 to 6 months)
  • Drink significant amounts of alcohol
  • Have a history of misusing laxatives, diet pills, diuretics, or insulin (if diabetic)
  • Have abnormal electrolytes before starting refeeding

How is refeeding syndrome managed?

The current approach is to start patients on a diet of approximately 2000 to 2500 calories/day increasing by 250 calories per day if electrolytes are stable. The goal is to gain 0.2 kg/day (almost ½ pound/day) while in the hospital. After the hospital stay, the expectation for weight gain is slower, with goals of 1 to 2 pounds per week. During this phase, energy needs may increase dramatically, with many patients requiring 3,500 to 4,500 calories/day to restore heart, brain and bone. These high metabolic needs are particularly important in children and adolescents who are still growing and developing.

Can anorexia nervosa be prevented?

Although it might not be possible to prevent all cases of anorexia nervosa, it is helpful to begin treatment in people as soon as they begin to have symptoms. In addition, teaching and encouraging healthy eating habits and realistic attitudes about food and body image also might be helpful in preventing the development or worsening of eating disorders. If your child or family member decides to become vegetarian or vegan, for instance, it is worth seeing a dietitian versed in eating disorders and touching base with your pediatrician or physician to make sure that this change occurs without a loss in nutrients.

What is the outlook for people with anorexia nervosa?

The prognosis for anorexia nervosa varies, based on the type of treatment, length of illness, and severity of the illness. Anorexia nervosa has the highest death rate of any mental illness. Individuals with anorexia nervosa are five times more likely to die prematurely and 18 times more likely to die of suicide.

Anorexia nervosa, like other eating disorders, gets worse the longer it is left untreated. The sooner the disorder is diagnosed and treated, the better the outcome. However, people with anorexia nervosa often will not admit they have a problem and might resist treatment or refuse to follow the treatment plan.

Anorexia nervosa can be treated, allowing the person to return to a healthy weight. Although treatment is possible, the risk of relapse is high. Recovery from anorexia usually requires long-term treatment as well as a strong commitment by the individual. Support of family members and other loved ones can help ensure that the person receives the needed treatment.

When should a person seek help?

If a serious physical illness is present (such as being very underweight), the individual should get prompt medical care. However, eating disorders are not necessarily dependent upon a person’s weight. In fact, even larger bodied people who have recently lost weight can have anorexia. If you suspect that you or someone you know has an eating disorder, seek help immediately. Eating disorders can become increasingly dangerous the longer they go untreated. In severe cases, eating disorders can be fatal.

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