Anorexia Nervosa Symptoms & Causes

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Our culture's obsession with achieving lower weight conveys an unavoidable message to maturing adolescents. According to the 2009 Youth Risk Behavior Survey, 33 percent of adolescent girls believed that they were overweight and 56 percent were attempting to lose weight.

Adolescents with unrealistic expectations about weight may end up suffering from anorexia nervosa. Read on to learn more about the causes and signs of anorexia nervosa, as well as how Children’s Hospital Boston can help young adults struggling with an eating disorder.


What causes anorexia nervosa?

It’s hard to pinpoint the cause of anorexia nervosa. The condition usually begins with dieting, but gradually progresses to extreme and unhealthy weight loss. There are several factors thought to be associated with anorexia:

  • Social attitudes toward body appearance — often unrealistic — are believed to play a large role.
  • Adolescents who develop anorexia are more likely to come from families with a history of weight problems, physical illness and mental health problems, such as depression or substance abuse. Genetics may also play a role.
  • Often teens with anorexia come from families with high levels of stress, poor patterns of communication, unrealistically high expectations and underdeveloped problem-solving skills.
  • Sports or activities in which leanness is emphasized (e.g., ballet, running or wrestling) and sports in which scoring is partly subjective (e.g., skating or gymnastics) are associated with a higher incidence of eating disorders.
  • Teens with anorexia often have other mental health problems, such as anxiety disorders, obsessive-compulsive disorder (OCD), affective (or mood) disorders and problems with substance abuse. They may also be dependent, immature in their emotional development and likely to isolate themselves from others.

What are the different types of anorexia nervosa?

There are two subgroups of anorexic behavior. Both have the goal of reducing calories:

  • restricting type— An adolescent severely limits the intake of food, especially food that contains fat.
  • binge/purge type— An adolescent restricts intake, and may then have a binge followed by a purging of calories.

Signs and symptoms

While each child may experience symptoms differently, some of the most common signs of anorexia include the following:

  • low body weight (under  85 percent of the normal weight for the child’s height and age)
  • intense fear of weight gain, even as he or she is losing weight
  • distorted view of body weight, size, or shape; sees himself or herself as too fat or normal sized, even when very underweight.
  • refusal to maintain normal body weight
  • in females, absence of three consecutive menstrual cycles without another cause
  • excessive physical activity
  • denies feelings of hunger
  • preoccupation with food preparation
  • bizarre eating behaviors (e.g., using a fork to eat raisins or cutting food into very small pieces)

Other symptoms may include:

  • dry skin
  • dehydration
  • abdominal pain or bloating
  • constipation
  • fatigue
  • hypothermia(problems maintaining normal body temperature) and feeling cold when others are hot
  • emaciation
  • development of lanugo (fine, downy body hair)
  • yellowing of the skin
  • stress fractures

If your child is struggling with anorexia, she may also be socially withdrawn, irritable, moody or depressed.

What are the warning signs to look out for?

Eating disorders are illnesses of denial and secrecy; they're often very difficult to track down. So family members and friends shouldn't feel badly about not figuring out right away if their loved one has a problem.

That being said, there are some signs you can look for:

  • unexplained weight loss
  • dizziness
  • fainting
  • fatigue
  • irritability or moodiness
  • going to the bathroom often, especially after meals
  • cutting food into tiny pieces and pushing it around the plate

Also be on the lookout for major change in eating or exercise behavior.

What are the potential complications of anorexia nervosa?

Anorexia is a serious disease. It can affect many systems of your child’s body, including:

  • cardiovascular (heart) — Complications may include mitral valve prolapse (a floppy valve in the heart), arrhythmias (a fast, slow or irregular heartbeat), bradycardia (slow heartbeat), hypotension (low blood pressure) and heart failure.
  • hematological (blood)— About one-third of anorexic adolescents have mild anemia (low red blood cell count). Leukopenia (low white blood cell count) occurs in up to 50 percent of anorexic adolescents.
  • gastrointestinal (stomach and intestines) —Normal movement in the intestinal tract often slows down with very restricted eating and severe weight loss. Gaining weight, and taking certain medications, can help to restore your child’s normal intestinal function.
  • renal (kidney) — Anorexia may cause dehydration, which can result in highly concentrated urine. Polyuria (increased production of urine) may also develop in anorexic patients when the kidneys start to lose their ability to concentrate urine. These changes usually return to normal when your child gets back to a normal weight.
  • endocrine (hormones)— One of the most telling symptoms of anorexia is amenorrhea, or when the menstrual cycle is missed for three or more consecutive cycles without any other underlying cause. Amenorrhea may appear before your child loses any amount of weight, and continue after her normal weight is restored. Adolescents with anorexia may also have lower levels of growth hormone, which may explain their failure to grow normally. Luckily, normal nutrition usually restores normal growth.

skeletal (bones) — If your child has anorexia, she is at an increased risk for low bone density. If the anorexic behavior has started before the bones have been fully formed (usually mid to late teens), she may have a greater risk of osteopenia (decreased bone tissue) or osteoporosis (bone loss) or fractures.


Researchers are actively exploring the question of whether anorexia can be prevented.

Awareness increases the chance of early detection and intervention — which in turn can reduce the severity of symptoms, enhance your child's normal growth and development and improve her quality of life.

Encouraging healthy eating habits and realistic attitudes toward weight and diet may also be helpful.

To some extent, parents can help prevent eating disorders in their children:
Here at Children’s Hospital Boston, our doctors encourage parents to avoid using food as a behavioral reward and to provide variety in appropriate portion sizes.

Parents should carefully monitor growth and development, helping their children avoid obesity through sensible eating and physical activity.

Parents should stress health and fitness—not “thinness.”

Long-term outlook

Treatment for anorexia nervosa is a slow process that may last years.

The vast majority of adolescents suffering from anorexia will enter a recovery phase, but there may be a lifelong struggle with food and consequent weight loss or gain.

The mortality rate for adolescents with anorexia is between three to five percent, and is usually caused by a cardiovascular problem such as heart failure. Suicide is also a significant risk in older adolescents.

Questions to ask your doctor

You and your family are key players in your child’s medical care. It’s important that you share your observations and ideas with your child’s health care provider, and that you understand your provider’s recommendations.

If you’ve made an appointment to talk to a doctor about your child’s eating and/or exercise habits, you probably already have some ideas and questions on your mind. But at the appointment, it can be easy to forget the questions you wanted to ask. It’s often helpful to jot them down ahead of time so that you can leave the appointment feeling that you have the information you need.

You may want to suggest that your child write down what she wants to ask her health care provider, too.

Some of the questions you may want to ask include:

  • How much experience do you have treating anorexia?
  • What are the treatment options?
  • How will we know whether the treatment is working?
  • Will my child need to be hospitalized?
  • What’s therapy and how does it work?
  • How will the treatment for anorexia affect my child’s day-to-day life?
  • What is the long-term outlook for my child?
  • What can I do to help support my child’s health and help her cope with her condition?

When to seek medical advice

If you notice changing eating or exercising habits in your child, it might mean that she has an eating disorder such as anorexia. You should make an appointment with your child’s pediatrician right away.

If your child has already been diagnosed with anorexia, you should call her doctor if you see any further change in your child’s behavior relating to food or exercise.

Useful medical terms

Anorexia Nervosa (Anorexia) is an eating disorder characterized by self-starvation with or without over-exercise or purging. Anorexia is a complex disease involving psychological, sociological and physiological elements.

Anxiety disorder is a generalized term used to describe mental health disorders relating to excess worrying, phobias and nervousness. A person suffering from an anxiety disorder may have panic attacks and may be unable to pursue normal daily routines.

Behavioral problem or disorder is a generalized term used when a child or teenager behaves—over a long period of time—in ways that are not socially acceptable for her age and situation or in ways that are destructive or self-destructive.

Bipolar disorder is a mood disorder characterized by severe mood swings. A person with this disorder may go from being manic, extremely elated and energetic to being depressed, sad, and sluggish. People with this disorder are sometimes known as “manic depressives.”

Bulimia Nervosa (commonly known as Bulimia) is an eating disorder characterized by extreme overeating or “binge” eating followed by self-induced vomiting, excessive exercising, inappropriate use of laxatives or enemas or fasting.

Clinician is an individual who is trained to practice medicine or psychological counseling and who works directly with people instead of in a laboratory.

Depression (clinical) is a mental health disorder characterized by a sad mood that is both prolonged and severe. Clinical depression can be treated with medication, therapy, and hospitalization if necessary.

Diagnostic evaluation refers to a clinician assessing the symptoms presented by your child in order to come to an informed opinion about what condition is causing those symptoms.

Dietician/Nutritionist refers to professionals with specialized training in nutrition. They, along with nurses and doctors, help families design healthy eating plans and provide long-term follow-up.

Mood disorder is a generalized term referring to mental health disorders where a person’s general mood is distorted or inappropriate given the circumstances. Clinical depression and bipolar disorder are both mood disorders.

Nurse Practitioner refers to a person with an Advanced Practice Nurse (APN) degree who manages patient care and provides primary care services as well as specialty services. Unlike most nurses, nurse practitioners can diagnose patients and prescribe medications.

Psychiatrist refers to a medical doctor who has specialized training in behavioral and mental health disorders. Psychiatrists can prescribe medication to their patients.

Psychologist refers to a mental health professional who is not a medical doctor and who does not prescribe medication. Clinical psychologists have extensive training in therapy and psychological testing.

Social Worker refers to a professional who patients and their families deal with the broad range of psychosocial issues and stresses related to coping with illness and maintaining health.

Center for Young Women's Health

Explore the Center's website for in-depth information on issues affecting teen girls today, including healthy eating, nutrition and eating disorders.


Talking about eating disorders

Read our Q & A with Sara Forman, MD, Director of Children's Outpatient Eating Disorders Program.

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