ICD-10 Codes:
Unspecified type: F50.00
Restricting type: F50.01
Binge eating/purging type: F50.02
Anorexia nervosa (AN) is part of a cluster of diagnoses called the feeding and eating disorders. Feeding and eating disorders are a group of psychiatric conditions that include:
Feeding and eating disorders are characterized by a persistent disturbance in eating behaviors. These disorders are linked to alterations in the consumption of food or absorption of nutrients, and can result in severe distress, physical health problems, and psychosocial impairment. People with anorexia nervosa are significantly underweight because they eat very little food in an effort to lose weight or prevent weight gain. People with binge eating disorder and bulimia nervosa eat large quantities of food in a short period of time (called a "binge"); people with bulimia nervosa also attempt to prevent weight gain by compensating for these binges in an inappropriate way, usually by vomiting, excessively exercising, fasting, or misusing laxatives or other medications. People with pica regularly eat non-nutritious, non-food substances. People with avoidant/restrictive food intake disorder have little interest in food or avoid many types of foods, which results in nutrition deficits.
Several of these disorders, including anorexia nervosa, bulimia nervosa, and binge eating disorder, are characterized by serious disturbances in body image and a preoccupation with weight and shape. Other disorders, including pica and avoidant/restrictive food intake disorder, are characterized by atypical eating behaviors but are not prominently associated with body image disturbances. Some feeding and eating disorders, including anorexia nervosa and avoidant/restrictive food intake disorder, cause the individual to be significantly underweight or malnourished as a result of their eating behaviors. Other disorders, including bulimia nervosa and binge eating disorder, do not produce marked weight loss and are typically associated with normal or higher than expected weight.
AN is a potentially life-threatening psychiatric disorder that affects 0.3 - 0.9% of adults. The disorder can occur in both men and women, but it is significantly more common in women.
AN is characterized by three primary symptoms:
Individuals with AN may globally fear becoming fat, or may believe that they are generally thin but that certain body parts are unacceptably fat. Checking behaviors are common; these can include measuring body parts, excessively weighing oneself, and excessively looking at oneself in the mirror. Preoccupation with food and food-related hoarding behaviors are also common. AN can be associated with poor insight; people with AN may consider their weight loss to be an accomplishment or sign of self-discipline, rather than a symptom of a serious illness.
Individuals with the binge-eating/purging type of AN engage in binge eating (eating an unusually large amount of food in a very short period of time) and/or purging (self-induced vomiting or misuse of laxatives, diuretics, or enemas). The binge-eating/purging type of AN is distinguished from bulimia nervosa primarily by the presence of significantly low body weight in AN. Individuals with the restricting type of AN do not engage in binging or purging behavior. For these individuals, weight loss is maintained primarily through dieting or fasting. Crossover between these types is fairly common; therefore, these specifiers are used to describe current behaviors (i.e., within the past three months).
AN is a potentially life-threatening condition. In severe cases, AN can adversely affect the functioning of multiple major organ systems, resulting in the need for inpatient hospitalization and nutritional rehabilitation.
Although some malnutrition-related impairments are reversible, others may have permanent adverse health consequences. Malnourishment and preoccupation with food and weight can lead to depression-like symptoms that impair school or work performance and interfere with social relationships. Many people with AN also have other psychiatric conditions, most commonly mood and anxiety disorders. Comorbidity with substance use disorders may also occur.
AN is characterized by abnormalities of brain function which are thought to contribute to symptoms. In particular, abnormalities in serotonergic inhibitory systems and dopaminergic reward systems have been observed. These abnormalities are thought to contribute to altered eating by allowing the individual with AN to inhibit motivational drives or by decreasing awareness of homeostatic needs. Childhood temperament and personality traits, including anxiety and perfectionism, are also thought to play a role in the development of AN. The disorder has a genetic component, although having a genetic predisposition to AN does not necessarily mean that someone will develop AN.
AN is treatable. Published treatment guidelines for AN include those from the American Psychiatric Association, the Society of Clinical Psychology, and the National Institute for Clinical Excellence.
The first step when treating AN is to evaluate the patient's physical health status and determine the level of care.
Inpatient hospitalization, residential treatment, partial hospitalization, or outpatient treatment may be appropriate depending on the patient's weight, cardiac status, behaviors, and social circumstances. Determination of level of care and corresponding interventions should be made in collaboration with a specialist.
Clinical research suggests that the following treatments are indicated for the treatment of adults with AN:
For more information about drug prescribing in AN, click here.
In addition, research suggests the following treatments are promising: