Bulimia Nervosa

Essential (Required) Features:

• Frequent, recurrent episodes of binge eating (e.g., once a week or more over a period of at least 1 month). Binge eating is defined as a discrete period of time (e.g., 2 hours) during which the individual experiences a loss of control over their eating behaviour and eats notably more or differently than usual. Loss of control over eating may be described by the individual as feeling like they cannot stop or limit the amount or type of food eaten; having difficulty stopping eating once they have started; or giving up even trying to control their eating because they know they will end up overeating.
• Repeated inappropriate compensatory behaviours to prevent weight gain (e.g., once a week or more over a period of at least 1 month). The most common compensatory behaviour is self-induced vomiting, which typically occurs within an hour of binge eating. Other inappropriate compensatory behaviours include fasting or using diuretics to induce weight loss, using laxatives or enemas to reduce the absorption of food, omission of insulin doses in individuals with diabetes, and strenuous exercise to greatly increase energy expenditure.
• Excessive preoccupation with body weight or shape. Preoccupation with weight or shape, when not explicitly reported, may be manifested by behaviours such as repeatedly checking body weight using scales; repeatedly checking one’s body shape using tape measures or reflection in mirrors; constantly monitoring the calorie content of food or searching for information on how to lose weight; or by extreme avoidant behaviours, such as refusal to have mirrors at home, avoidance of tight-fitting clothes, or refusal to know one’s weight or purchase clothing with specified sizing.
• There is marked distress about the pattern of binge eating and inappropriate compensatory behaviour or significant impairment in personal, family, social, educational, occupational or other important areas of functioning.
• The symptoms do not meet the diagnostic requirements for Anorexia Nervosa.

Additional Clinical Features:

• Binge eating episodes may be ‘objective’, in which the individual eats an amount of food that is larger than what most people would eat under similar circumstances, or ‘subjective’, which may involve eating amounts of food that might be objectively considered to be within normal limits but are subjectively experienced as large by the individual. In either case, the core feature of a binge eating episode is the experience of loss of control over eating.
• Additional characteristics of binge eating episodes may include eating much more rapidly than usual, eating until feeling uncomfortably full, eating large amounts of food when not feeling physically hungry, or eating alone because of embarrassment.
• Binge eating is typically experienced as very distressing. This is often manifested in negative emotions such as guilt, disgust, or shame, which also typically negatively affect the individual’s self-evaluation.
• Bulimia Nervosa may be associated with weight gain over time. However, individuals with Bulimia Nervosa may be of normal weight or even low weight (though not sufficiently low to meet the diagnostic requirements for Anorexia Nervosa). The diagnosis of Bulimia Nervosa is based on the presence of regular binge eating and inappropriate compensatory behaviours, regardless of overweight status.

Boundary with Normality (Threshold):

• Infrequent overeating or feasting during culturally sanctioned holidays or occasional celebrations should not be characterized as binge eating for the purpose of assigning a diagnosis of Bulimia Nervosa. Similarly, exercise qualifies as inappropriate compensatory behaviour only if it is unusually intensive or prolonged, or is carried out to the exclusion of other activities or in spite of fatigue, pain or injury.

Course Features:

• Bulimia Nervosa is characterized by a variable course that can manifest as persistent symptoms or intermittent episodes of remission and exacerbation. Outcome appears to be related to course such that individuals whose symptoms remit for a period longer than one year tend not to experience relapse of the disorder.
• Individuals with Bulimia Nervosa are at a significantly increased risk for substance use, suicidality, and health complications (e.g., gastrointestinal problems) that can lead to premature death.
• Some individuals may cease purging or compensatory behaviours but continue to engage in binge eating. In this case, the diagnosis may be changed to Binge Eating Disorder if all diagnostic requirements are met.
• Stressful life events or a history of Anorexia Nervosa increase the likelihood of the onset of Bulimia Nervosa. A restricting pattern in Anorexia Nervosa may evolve over time into a pattern of binging and purging in Bulimia Nervosa. In such cases, the diagnosis may be changed to Bulimia Nervosa after 1 year during which body weight has not been sufficiently low to meet the diagnostic requirements of Anorexia Nervosa.

Developmental Presentations:

• Onset of Bulimia Nervosa typically occurs during or shortly after puberty. Young children do not commonly engage in binge-eating due to a lack of access and control of food availability.

Culture-Related Features:

• The prevalence of Bulimia Nervosa is higher in cultures characterized by an idealized thin body ideal. In addition, the prevalence of Bulimia Nervosa is increasing in countries that are industrializing and transitioning to more global and urbanized societies.
• The distribution of Bulimia Nervosa across cultural groups within a society can change over time. For example, in the United States, the incidence of the disorder appears to be decreasing among Euro-American females and increasing among ethnic minority groups, particularly Latinos and African-Americans.
• Purging methods may be locally specific, such as the use of herbal purgatives in Asia and the Pacific region (e.g., seaweed and herbal teas in Japan; indigenous tea in Fiji) and justified with medicinal or other rationales that may obscure their pathological significance.

Sex- and/or Gender-Related Features:

• Bulimia Nervosa is more common in females than males.
• Males are less likely than females to engage in purging behaviours and have a greater tendency to use excessive exercise or steroids as compensatory behaviours in response to binges. Males are also less likely to seek treatment.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Anorexia Nervosa: Individuals with Anorexia Nervosa may engage in binge eating and purging, but can be distinguished from individuals with Bulimia Nervosa by their very low body weight. If binge eating and purging are associated with very low body weight (i.e., BMI of less than 18.5 kg/m2 in adults and BMI-for-age under 5th percentile in children and adolescents) and all the other diagnostic requirements are met, a diagnosis of Anorexia Nervosa, Binge-Purge pattern rather Bulimia Nervosa should be assigned. Moreover, a significant proportion of individuals with Anorexia Nervosa continue to exhibit binging or purging behaviours after they have regained a more normal weight. In such cases, the diagnosis may be changed to Bulimia Nervosa after 1 year during which body weight has not been sufficiently low to meet the diagnostic requirements of Anorexia Nervosa.
• Boundary with Binge Eating Disorder: Binge eating that is not associated with regular compensatory behaviours should be diagnosed as Binge Eating Disorder rather than Bulimia Nervosa.