In This Section:
Information On Eating Disorders
Signs, Symptoms, and How to Help
Prevalence Of Eating Disorders
How to Help Students With Eating Disorders

Information On Eating Disorders

Eating disorders are characterized by a persistent pattern of atypical eating or dieting behavior. These patterns of eating are associated with significant physical and emotional distress, and interfere with work, school, and relationships.

The line between normal variations in eating and eating disorders can be hard to delineate. Formal diagnoses are best made by clinicians on the basis of specific criteria from The Diagnostic and Statistical Manual of Mental Disorders. The following descriptive information provides a basic overview of eating disorders. Please note that although most individuals with eating disorders are female, these criteria and descriptions also apply to the 5-10% of individuals with these disorders who are male.

ANOREXIA NERVOSA

Individuals with anorexia nervosa are unable or unwilling to maintain a body weight that is normal for their age and height. There is no precise boundary dividing "normal" from "too low", but most clinicians use 85% or less of normal weight as a cut-off for anorexia. Individuals with anorexia nervosa usually display a pronounced fear of weight gain and a dread of becoming fat even though they are markedly underweight. Concerns about their weight and about how they believe they look have a powerful influence on their self-image. The seriousness of the weight loss and its health implications is usually minimized, if not denied, by the individual. Women with the diagnosis of anorexia nervosa have missed at least three consecutive menstrual cycles.

There have been recent refinements in the diagnostic criteria for this eating disorder. The diagnosis of anorexia nervosa now includes two subtypes of the disorder that describe two behavioral patterns. Individuals with the Restricting Type maintain their low body weight purely by restricting food intake and, possibly, by exercise. Those with Binge-Eating/Purging Type restrict food intake as well, but also regularly engage in binge eating and/or purging behaviors such as self-induced vomiting or the misuse of laxatives, diuretics or enemas. Available data indicate that the Binge-Eating/Purging Type of Anorexia Nervosa is frequently associated with other impulse control problems, substance misuse and mood lability.

BULIMIA NERVOSA

Individuals with bulimia nervosa regularly engage in discrete periods of overeating which are followed by attempts to compensate for overeating and to avoid weight gain. There can be considerable variation in the nature of the overeating, but a typical episode of overeating involves the consumption of an amount of food that would be considered excessive under normal circumstances. The individual experiences a sense of a lack of control over the binge eating. The binge eating episode is followed by attempts to "undo" the consequences of binge eating though self-induced vomiting, misusing laxatives, enemas, diuretics, severe caloric restriction, or excessive exercising.

Individuals with bulimia nervosa are also preoccupied with weight and shape, and their self-image is closely tied to their perception of the way they look.

The formal diagnosis of bulimia nervosa requires that the individual not meet criteria for anorexia nervosa. (In other words, if an individual simultaneously meets criteria for both anorexia nervosa and bulimia nervosa, only the diagnosis of Anorexia Nervosa, binge-eating/purging type is given.) The criteria also specify minimal frequency and duration cut-offs for the diagnosis: individuals must binge eat and engage in inappropriate compensatory behavior at least twice weekly for three months.

As with anorexia nervosa, there are two subtypes of bulimia nervosa. The Purging Type describes individuals who regularly compensate for the binge eating with self-induced vomiting or through the use of laxatives, diuretics, or enemas. The Non-Purging Type is used to describe individuals who compensate through excessive exercising or through dietary fasting.

BINGE EATING DISORDER

The term, Binge Eating Disorder (BED), was officially introduced in 1992. The term was developed to describe individuals who binge eat but do not regularly use inappropriate compensatory weight control behaviors such as fasting or purging to lose weight. The eating may involve rapid consumption of food, uncomfortable fullness after eating, and eating large amounts of food when not hungry. Feelings of shame and embarrassment are prominent. Binge Eating Disorder is often associated with obesity. In the past these individuals were often referred to as compulsive overeaters, emotional overeaters, or food addicts. Available research evidence suggests that approximately one fifth of the people who seek professional treatment for obesity meet the criteria for Binge Eating Disorder. In the DSM IV, binge eating disorder is not an officially recognized eating disorder but is included in the category titled Eating Disorder Not Otherwise Specified.

EATING DISORDERS NOT OTHERWISE SPECIFIED (EDNOS)

There are numerous variants of disordered eating in addition to binge eating disorder that do not meet the diagnostic criteria for anorexia nervosa or bulimia nervosa, but nevertheless are eating disorders requiring treatment. A substantial number of individuals with eating disorders fit only this category. Those with eating disordered behaviors that resemble anorexia nervosa or bulimia nervosa but whose eating behaviors do not meet one or more essential diagnostic criteria may be diagnosed with EDNOS. Examples of EDNOS include individuals who regularly purge but do not binge eat, individuals who meet criteria for anorexia nervosa but continue to menstruate, and individuals who meet criteria for bulimia nervosa, but binge eat less than twice weekly.

The diagnostic scheme endorsed by the American Psychiatric Association has been criticized since a substantial fraction of patients requesting treatment for eating disorders do not meet formal diagnostic criteria for either Anorexia Nervosa or Bulimia Nervosa. More community-based studies are needed to fully characterize the complete range of eating disorders.

SUMMARY

The diagnosis of an eating disorder can be difficult. The boundaries between normal and disordered eating are somewhat blurry. Many patients with clearly disordered eating do not meet the formal diagnostic criteria for one of the specific disorders and are classified as having Eating Disorder NOS. The failure to meet formal criteria does not necessarily mean that the individual does not have a serious and significant disorder. Formal evaluations for diagnosis and treatment should only be made by qualified clinicians.