What are eating disorders?
Individuals with anorexia nervosa are unable or unwilling to maintain a body weight that is normal or expected for their age and height. There is no precise boundary dividing “normal” from “too low”, but most clinicians use 85% of normal weight as a reasonable guide.
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 the individual’s self-evaluation. The seriousness of the weight loss and its health implications is usually minimized, if not denied, by the individual.
The diagnosis of anorexia nervosa 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. Individuals with the binge-eating/purging type usually restrict their 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 more frequently associated with other impulsive behaviors, substance use disorders and mood lability. The longer a person has anorexia nervosa, the more likely they are to binge and purge.
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 the typical episode of overeating involves the consumption of an amount of food that would be considered excessive in normal circumstances. The individual’s subjective experience is dominated by a sense of a lack of control over the eating.
Binge eating is followed by attempts to “undo” the consequences of eating too much though behaviors such as self-induced vomiting, misuse of laxatives, enemas, diuretics, severe caloric restriction, or excessive exercising. Profound concerns about weight and shape are also characteristic of individuals with bulimia nervosa. Self-evaluation is centered on the individual’s perceptions of her body image.
Binge Eating Disorder
The term, binge eating disorder, was officially introduced in 1992 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 binge eating may involve rapid consumption of food with a sense of loss of control, uncomfortable fullness after eating, and eating large amounts of food when not hungry. Feelings of shame and embarrassment are prominent.
Other Eating Disorders
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. Individuals 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.