Anorexia Nervosa

What Causes Anorexia Nervosa

Physical effects

Psychological effects

Anorexia Nervosa Criteria for Diagnosis


Warning signs of Anorexia

Promoting good eating habits and a positive body image

Anorexia and the Internet

When to seek medical advice


Anorexia Nervosa (AN) is an eating disorder that typically affects adolescent girls, with an average prevalence of 0.3% in young women. [1] The word “anorexia” means loss of appetite, a symptom in other diseases.  Most people with the diagnosis of Anorexia Nervosa are referred to as having “anorexia,” which is technically not correct. In many ways, people with AN do not lose their appetite, but rather are preoccupied with food.  Anorexia Nervosa is characterized by weight loss, a distorted perception of body shape and size, and an intense fear of weight gain.  Frequently, there is also a level of denial about the seriousness of the degree of weight loss.  In this knol, when we refer to “Anorexia” we are referring to Anorexia Nervosa (AN).


While anorexia typically affects females, increasing numbers of males are being diagnosed.  Additionally, while patients tend to be adolescents and young adults, increasingly patients of all ages, including children and middle-aged adults are being seen as well.  In the United States, persons suffering from anorexia are from all different races and ethnicities.



The exact cause of Anorexia Nervosa is unknown, but there are believed to be several different factors that may lead to its development.  These include biological and genetic factors, psychological factors, and socio-cultural influences. Eating disorders, including anorexia, run in families, with higher rates among females with identical twins and/or first degree relatives with eating disorders.  Psychological factors that have been shown to be associated with anorexia include perfectionism, anxiety, obsessive, low self-esteem, and low self-confidence.   Society’s increasing emphasis on a thin body ideal may also be a factor, and may further increase low self-esteem and low confidence, resulting in dieting and further preoccupation with thinness.


Over the last few years, the modeling world has responded to this, with at least two countries instituting body mass index (BMI) cut offs for models to be allowed to participate as runway models in corresponding fashion weeks.  The BMI that they established as a cutoff was 18.0 which still constitutes extreme thinness for a young woman, and according to the World Health Organization still would be defined as “underweight.”[2]  The Council for Fashion Designers in America opted not to create BMI cut offs for models in the US.


PHYSICAL EFFECTS of Anorexia Nervosa

Anorexia Nervosa is a complex mental health disorder with significant physiological effects and an associated environmental overlay.  Most of the physical effects and many of the initial alterations in cognitive functioning are due to the degree of malnutrition.



There is no single blood test or study that a clinician can use to diagnose Anorexia Nervosa, rather AN should be suspected any time an adolescent develops significant weight loss and food avoidance. Other medical diseases should be ruled out prior to making a diagnosis of AN, such as gastrointestinal illnesses, endocrine problems, and certain types of cancer (see Table 1).




Inflammatory bowel disease including Ulcerative Colitis and Crohn’s Disease

Malabsorptive conditions including Celiac Disease

Diabetes Mellitus


Collagen vascular disease including systemic lupus erythematous

Central nervous system tumors


Chronic infections such as tuberculosis and human immunodeficiency virus (HIV)

Obsessive Compulsive Disorder

Anxiety disorders

Mood disorders such as depression


Substance abuse


AN is diagnosed using a number of clinical criteria. The criteria for AN are listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV):[4]

1.     Refusal to maintain a minimally normal body weight for age and height

2.     Intense fear of weight gain or becoming fat, although underweight

3.     Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self evaluation, or denial of the seriousness of the current low body weight.

4.     In post menarcheal females, amenorrhea, that is the absence of at least three consecutive menstrual cycles

There are two subtypes of AN that are described

1. Restricting type: During the current episode of anorexia nervosa, the person has not regularly engaged in binge-eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas)

2. Binge eating/Purging subtype: During the current episode of anorexia nervosa, the person has regularly engaged in binge-eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas).


Many patients may fulfill some of the criteria for anorexia nervosa, but not all of them. They still may struggle with problems with eating and/or problems with body image.  They may receive a diagnosis of a “partial eating disorder” or eating disorder not otherwise specified (ed-nos).


The criteria for Eating Disorder NOS according to the DSM IV include:

1.     Meet all the criteria for anorexia nervosa, except still have normal periods

2.     Meet all the criteria for anorexia nervosa, however their weight is still within a normal range.

3.     Meet all the criteria for anorexia nervosa; however maintain a normal body image.

4.     Meet all the criteria for bulimia nervosa, except the frequency of binging and purging is less than that specified by the DSM IV necessary to make a diagnosis of bulimia nervosa.

5.     Repeatedly chew and spit out but do not swallow their food

6.     Binge-eat but do not purge (also known as Binge Eating Disorder)


Despite a difference in the diagnosis, the treatment will be similar, as those who suffer from Anorexia Nervosa, Bulimia Nervosa, and Eating Disorder-NOS all share a pre-occupation with food, as well as with body weight and shape.



One of the keys to successful treatment of anorexia is early recognition of the problem and early intervention.  Children and adolescents must be weighed and measured at every medical appointment or at a minimum once a year.  A Body Mass Index (BMI) should be calculated and plotted on a growth curve appropriate for the adolescent’s age and gender.  BMI is a tool to screen a person’s nutritional status and is calculated by taking the weight in kilograms and dividing by the height (in meters) squared (BMI = kg/m2). [5],[6]



Successful treatment typically requires a multidisciplinary team knowledgeable in the care of patients with eating disorders.  The team should include:

•      A physician who can monitor weight, vital signs and other consequences due to malnutrition;

•      A dietician or nutritionist who can assist with meal planning, and weight restoration; and

•      A therapist who is knowledgeable about treating eating disorders.


GOALS OF TREATMENT of Anorexia Nervosa

The goals of treatment include immediate weight restoration (returning the patient to a healthy, stable weight). Weight restoration is the critical first step to enable the patient to be capable of benefiting from psychological treatment. Psychological treatment aims to improve the patient’s body distortion and intense fear of becoming fat in addition to symptoms of anxiety and or depression that may also exist.  In the long term, additional goals include resumption of normal menstrual periods, and improved psychological functioning.


Nutritional treatment typically occurs with the guidance of a dietician  The goal is to resume healthy eating habits and patterns. A dietician may develop a meal plan for a patient to ensure they are obtaining optimal calories in addition to resuming well balanced eating habits.  Patients will typically need to increase the variation in the types of food they are eating.  As patients are improving their nutrition and restoring their weight, they often require zinc supplementation and typically benefit from a multivitamin and calcium and vitamin D supplementation.


For adolescents with AN, family therapy is an effective psychotherapeutic treatment.[7]Typically treatment occurs as an outpatient. Treatment may require inpatient hospitalization for medical stabilization. At times, an intensive outpatient or partial hospitalization may be more beneficial.  For patients who are not responding to outpatient treatment but who are medically stable, residential treatment programs may be necessary.


The benefits of psychotropic medication, including antidepressants and atypical neuroleptic medications, is unclear, and further research is necessary..[8], [9]Antidepressant medications, particularly selective serotonin reuptake inhibitors (SSRIs)may be beneficial in treating co-existing symptoms of depression or obsessive-compulsive disorder.   Malnutrition itself may worsen symptoms of anxiety, depression, and obsessive behavior.  It is important to reevaluate symptoms throughout the treatment and recovery process. If symptoms persist following weight restoration, medications may be more effective in treating those symptoms.  Depression, anxiety, and substance abuse are the most common other mental health disorders that occur among people with anorexia.



At times patients may be severely malnourished, requiring acute medical hospitalization. These patients will require being refed in hospital under close surveillance to monitor for “refeeding syndrome.” When the body is severely malnourished, it is in a catabolic state, when the tissues are breaking down into simpler metabolic constituents.  When a patient begins to eat again, there is a surge of insulin as the body switches to an anabolic state, when the body’s chemical processes are constructive, or synthesizing tissues, enzymes and other components.  This surge of insulin can cause shifts in electrolytes, in particular phosphorous, potassium, and magnesium as well as shifts of sodium and water.  The results can lead to cardiac arrhythmias, breakdown of muscle, edema (swelling in the hands and feet), delirium, and even death.



Generally, adolescents have better outcomes than adults, which may be due to a shorter length of symptoms among adolescents.  Other good prognostic factors include: early identification and entry into treatment, short duration of symptoms, age less than 14 years, no binging and purging (the restricting subtype of anorexia rather than the binge/purge subtype), and no other mental health disorder (such as depression, anxiety, or substance abuse).[10]  Fifty percent of adolescents are thought to have a good outcome; however, recovery can take many years.[11]


The leading causes of death due to anorexia are by suicide, or secondary to medical complications of malnutrition/starvation.  Mortality rates range from 2% to 8%.



•      Someone who appears to becoming thinner and thinner

•      Someone who is not gaining weight in a reasonable and expected manner as they are going through puberty

•      Complains about being fat when obviously is not

•      Skipping meals

•      Making frequent excuses for not eating-“I’m not hungry, I’m too busy, I don’t eat that…”

•      Someone who continues to diet or lose weight even though he/or she is not overweight

•      May complain frequently of feeling cold, when others do not

•      Complains about feeling full even after only eating a small amount of food

•      Socially withdraws from activities, particularly activities around food (like going out for dinner or eating with their family)

•      Repeatedly weighs themselves

•      Engages in prolonged periods of exercise even when feeling tired or weak

•      Obsessive calorie counting

•      Eating rituals such as eating the same food for lunch every day, or needing to cut food into tiny pieces and pushing it around the plate rather than eating it

•      Collecting recipes and cooking for others while finding excuses to avoid eating

•      Becomes disgusted with foods that were previously favorites



1.     Parents should be good role models for their children, with healthy eating and exercise habits

2.     Don’t make negative comments about your own body or anyone else’s

3.     Recognize that there are a range of body shapes and sizes

4.     Don’t judge a person based on their weight or size, it does not reflect the type of person they are

5.     Encourage family meals

6.     Encourage regular healthy exercise



The majority of Web sites provide a medical view of anorexia, which defines anorexia as a mental health disorder that can be cured.  These Web sites and online communities are run by professionals in addition to those suffering with an eating disorder or a history of an eating disorder.  These resources may provide information and support to current sufferers and their friends and family.


Additionally, there is another group of Web sites, which argue that anorexia is not an illness but rather a “lifestyle choice.”  These pro-anorexia or pro-ana Web sites may contain dangerous and unhealthy information including weight loss-tips and support of the perpetuation of eating disorders.  These Web sites have an unclear impact, however they may foster the development of an eating disorder in a vulnerable adolescent or young adult. [12]



If you are concerned that you may have an eating disorder, see your doctor and express your concerns. Often the grip of anorexia can be so strong, you may resist getting help. Try to find support from a friend or family member to assist you in finding treatment options. 

These articles are for informational purposes only and are not intended to replace medical or medical diagnosis. You are responsible for your actions, treatment or medical care and should consult with your physician or other health care professional for any questions you may have about your health. Tag: Health tips; hair care; yoga; Take care of your skin; meditation; snacks; child health; Mental health; gastronomy;