307.51 Bulimia Nervosa

Diagnostic Features

The essential features of Bulimia Nervosa are binge eating and inappropriate compensatory methods to prevent weight gain. In addition, the self-evaluation of individuals with Bulimia Nervosa is excessively influenced by body shape and weight. To qualify for the diagnosis, the binge eating and the inappropriate compensatory behaviors must occur, on average, at least twice a week for 3 months (Criterion C).

A binge is defined as eating in a discrete period of time an amount of food that is definitely larger than most individuals would eat under similar circumstances (Criterion A1). The clinician should consider the context in which the eating occurred-what would be regarded as excessive consumption at a typical meal might be considered normal during a celebration or holiday meal. A "discrete period of time" refers to a limited period, usually less than 2 hours. A single episode of binge eating need not be restricted to one setting. For example, an individual may begin a binge in a restaurant and then continue it on returning home. Continual snacking on small amounts of food throughout the day would not be considered a binge.

Although the type of food consumed during binges varies, it typically includes sweet, high-calorie foods such as ice cream or cake. However, binge eating appears to be characterized more by an abnormality in the amount of food consumed than by a craving for a specific nutrient, such as carbohydrate. Although individuals with Bulimia Nervosa consume more calories during an episode of binge eating than persons without Bulimia Nervosa consume during a meal, the fractions of calories derived from protein, fat, and carbohydrate are similar.

Individuals with Bulimia Nervosa are typically ashamed of their eating problems and attempt to conceal their symptoms. Binge eating usually occurs in secrecy, or as inconspicuously as possible. An episode may or may not be planned in advance and is usually (but not always) characterized by rapid consumption. The binge eating often continues until the individual is uncomfortably, or even painfully, full. Binge eating is typically triggered by dysphoric mood states, interpersonal stressors, intense hunger following dietary restraint, or feelings related to body weight, body shape, and food. Binge eating may transiently reduce dysphoria, but disparaging self-criticism and depressed mood often follow.

An episode of binge eating is also accompanied by a sense of lack of control (Criterion A2). An individual may be in a frenzied state while binge eating, especially early in the course of the disorder. Some individuals describe a dissociative quality during, or following, the binge episodes. After Bulimia Nervosa has persisted for some time, individuals may report that their binge-eating episodes are no longer characterized by an acute feeling of loss of control, but rather by behavioral indicators of impaired control, such as difficulty resisting binge eating or difficulty stopping a binge once it has begun. The impairment in control associated with binge eating in Bulimia Nervosa is not absolute; for example, an individual may continue binge eating while the telephone is ringing, but will cease if a roommate or spouse unexpectedly enters the room.

Another essential feature of Bulimia Nervosa is the recurrent use of inappropriate compensatory behaviors to prevent weight gain (Criterion B). Many individuals with Bulimia Nervosa employ several methods in their attempt to compensate for binge eating. The most common compensatory technique is the induction of vomiting after an episode of binge eating. This method of purging is employed by 80%-90% of individuals with Bulimia Nervosa who present for treatment at eating disorders clinics. The immediate effects of vomiting include relief from physical discomfort and reduction of fear of gaining weight. In some cases, vomiting becomes a goal in itself, and the person will binge in order to vomit or will vomit after eating a small amount of food. Individuals with Bulimia Nervosa may use a variety of methods to induce vomiting, including the use of fingers or instruments to stimulate the gag reflex. Individuals generally become adept at inducing vomiting and are eventually able to vomit at will. Rarely, individuals consume syrup of ipecac to induce vomiting. Other purging behaviors include the misuse of laxatives and diuretics. Approximately one-third of those with Bulimia Nervosa misuse laxatives after binge eating. Rarely, individuals with the disorder will misuse enemas following episodes of binge eating, but this is seldom the sole compensatory method employed.

Individuals with Bulimia Nervosa may fast for a day or more or exercise excessively in an attempt to compensate for binge eating. Exercise may be considered to be excessive when it significantly interferes with important activities, when it occurs at inappropriate times or in inappropriate settings, or when the individual continues to exercise despite injury or other medical complications. Rarely, individuals with this disorder may take thyroid hormone in an attempt to avoid weight gain. Individuals with diabetes mellitus and Bulimia Nervosa may omit or reduce insulin doses in order to reduce the metabolism of food consumed during eating binges.

Individuals with Bulimia Nervosa place an excessive emphasis on body shape and weight in their self-evaluation, and these factors are typically the most important ones in determining self-esteem (Criterion D). Individuals with this disorder may closely resemble those with Anorexia Nervosa in their fear of gaining weight, in their desire to lose weight, and in the level of dissatisfaction with their bodies. However, a diagnosis of Bulimia Nervosa should not be given when the disturbance occurs only during episodes of Anorexia Nervosa (Criterion E).

Subtypes

The following subtypes can be used to specify the presence or absence of regular use of purging methods as a means to compensate for the binge eating:

• Purging Type. This subtype describes presentations in which the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas during the current episode.
• Nonpurging Type. This subtype describes presentations in which the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas during the current episode.

Associated Features and Disorders

Associated descriptive features and mental disorders.

Individuals with Bulimia Nervosa typically are within the normal weight range, although some may be slightly underweight or overweight. The disorder occurs but is uncommon among moderately and morbidly obese individuals. There are suggestions that, prior to the onset of the Eating Disorder, individuals with Bulimia Nervosa are more likely to be overweight than their peers. Between binges, individuals with Bulimia Nervosa typically restrict their total caloric consumption and preferentially select low-calorie ("diet") foods while avoiding foods they perceive to be fattening or likely to trigger a binge.

There is an increased frequency of depressive symptoms (e.g., low self-esteem) or Mood Disorders (particularly Dysthymic Disorder and Major Depressive Disorder) in individuals with Bulimia Nervosa. In many or most individuals, the mood disturbance begins at the same time as or following the development of Bulimia Nervosa, and individuals often ascribe their mood disturbances to Bulimia Nervosa. However, in some individuals, the mood disturbance clearly precedes the development of Bulimia Nervosa. There may also be an increased frequency of anxiety symptoms (e.g., fear of social situations) or Anxiety Disorders. These mood and anxiety disturbances frequently remit following effective treatment of Bulimia Nervosa. The lifetime prevalence of Substance Abuse or Dependence, particularly involving alcohol or stimulants, is at least 30% among individuals with Bulimia Nervosa. Stimulant use often begins in an attempt to control appetite and weight. A substantial portion of individuals with Bulimia Nervosa also have personality features that meet criteria for one or more Personality Disorders (most frequently Borderline Personality Disorder).

Preliminary evidence suggests that individuals with Bulimia Nervosa, Purging Type, show more symptoms of depression and greater concern with shape and weight than individuals with Bulimia Nervosa, Nonpurging Type.

Associated laboratory findings.

Frequent purging behavior of any kind can produce fluid and electrolyte abnormalities, most frequently hypokalemia, hyponatremia, and hypochloremia. The loss of stomach acid through vomiting may produce a metabolic alkalosis (elevated serum bicarbonate), and the frequent induction of diarrhea through laxative abuse can cause metabolic acidosis. Some individuals with Bulimia Nervosa exhibit mildly elevated levels of serum amylase, probably reflecting an increase in the salivary isoenzyme.

Associated physical examination findings and general medical conditions.

Recurrent vomiting eventually leads to a significant and permanent loss of dental enamel, especially from lingual surfaces of the front teeth. These teeth may become chipped and appear ragged and "moth-eaten." There may also be an increased frequency of dental cavities. In some individuals, the salivary glands, particularly the parotid glands, may become notably enlarged. Individuals who induce vomiting by manually stimulating the gag reflex may develop calluses or scars on the dorsal surface of the hand from repeated trauma from the teeth. Serious cardiac and skeletal myopathies have been reported among individuals who regularly use syrup of ipecac to induce vomiting.

Menstrual irregularity or amenorrhea sometimes occurs among females with Bulimia Nervosa; whether such disturbances are related to weight fluctuations, to nutritional deficiencies, or to emotional stress is uncertain. Individuals who chronically abuse laxatives may become dependent on their use to stimulate bowel movements. The fluid and electrolyte disturbances resulting from the purging behavior are sometimes sufficiently severe to constitute medically serious problems. Rare but potentially fatal complications include esophageal tears, gastric rupture, and cardiac arrhythmias. Rectal prolapse has also been reported among individuals with this disorder. Compared with individuals with Bulimia Nervosa, Nonpurging Type, those with the Purging Type are much more likely to have physical problems such as fluid and electrolyte disturbances.

Specific Culture, Age, and Gender Features

Bulimia Nervosa has been reported to occur with roughly similar frequencies in most industrialized countries, including the United States, Canada, Europe, Australia, Japan, New Zealand, and South Africa. Few studies have examined the prevalence of Bulimia Nervosa in other cultures. In clinical studies of Bulimia Nervosa in the United States, individuals presenting with this disorder are primarily white, but the disorder has also been reported among other ethnic groups.

In clinic and population samples, at least 90% of individuals with Bulimia Nervosa are female. Some data suggest that males with Bulimia Nervosa have a higher prevalence of premorbid obesity than do females with Bulimia Nervosa.

Prevalence

The lifetime prevalence of Bulimia Nervosa among women is approximately 1%-3%; the rate of occurrence of this disorder in males is approximately one-tenth of that in females.

Course

Bulimia Nervosa usually begins in late adolescence or early adult life. The binge eating frequently begins during or after an episode of dieting. Disturbed eating behavior persists for at least several years in a high percentage of clinic samples. The course may be chronic or intermittent, with periods of remission alternating with recurrences of binge eating. However, over longer-term follow-up, the symptoms of many individuals appear to diminish. Periods of remission longer than 1 year are associated with better long-term outcome.

Familial Pattern

Several studies have suggested an increased frequency of Bulimia Nervosa, of Mood Disorders, and of Substance Abuse and Substance Dependence in the first-degree biological relatives of individuals with Bulimia Nervosa. A familial tendency toward obesity may exist, but this has not been definitively established.

Differential Diagnosis

Individuals whose binge-eating behavior occurs only during Anorexia Nervosa are given the diagnosis Anorexia Nervosa, Binge-Eating/Purging Type, and should not be given the additional diagnosis of Bulimia Nervosa. For an individual who binges and purges but whose presentation no longer meets the full criteria for Anorexia Nervosa, Binge-Eating/Purging Type (e.g., when weight is normal or menses have become regular), it is a matter of clinical judgment whether the most appropriate current diagnosis is Anorexia Nervosa, Binge-Eating/Purging Type, In Partial Remission, or Bulimia Nervosa.

In certain neurological or other general medical conditions, such as Kleine-Levin syndrome, there is disturbed eating behavior, but the characteristic psychological features of Bulimia Nervosa, such as overconcern with body shape and weight, are not present. Overeating is common in Major Depressive Disorder, With Atypical Features, but such individuals do not engage in inappropriate compensatory behavior and do not exhibit the characteristic overconcern with body shape and weight. If criteria for both disorders are met, both diagnoses should be given. Binge-eating behavior is included in the impulsive behavior criterion that is part of the definition of Borderline Personality Disorder. If the full criteria for both disorders are met, both diagnoses can be given.

Diagnostic criteria for 307.51 Bulimia Nervosa

1. Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:
   1. eating, in a discrete period of time (e.g., within any 2-hour period), an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances
   2. a sense of lack of control over eating during the episode (e.g., a feeling that one cannot stop eating or control what or how much one is eating)
2. Recurrent inappropriate compensatory behavior in order to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise.
3. The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for 3 months.
4. Self-evaluation is unduly influenced by body shape and weight.
5. The disturbance does not occur exclusively during episodes of Anorexia Nervosa.

Specify type:

• Purging Type: during the current episode of Bulimia Nervosa, the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas
• Nonpurging Type: during the current episode of Bulimia Nervosa, the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas

Reprinted with permission from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision^TM. Copyright 2000 American Psychiatric Association. All Rights Reserved.