Individuals with bulimia nervosa may use a variety of methods to induce vomiting, includ- ing 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, indi- viduals consume syrup of ipecac to induce vomiting. Other purging behaviors include the misuse of laxatives and diuretics. A number of other compensatory methods may also be used in rare cases. Individuals with bulimia nervosa may misuse enemas following epi- sodes of binge eating, but this is seldom the sole compensatory method employed. Individ- uals 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 may fast for a day or more or exercise excessively in an attempt to prevent weight gain. Exercise may be considered excessive when it significantly interferes with im- portant activities, when it occurs at inappropriate times or in inappropriate settings, or when the individual continues to exercise despite injury or other medical complications.
Individuals with bulimia nervosa place an excessive emphasis on body shape or weight in their self-evaluation, and these factors are typically extremely important 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 (Cri- terion E).
Individuals with bulimia nervosa typically are within the normal weight or overweight range (body mass index [BMI] 2 18.5 and < 30 in adults). The disorder occurs but is un- common among obese individuals. Between eating binges, individuals with bulimia ner- (”diet") foods while avoiding foods that they perceive to be fattening or likely to trigger a binge.
Menstrual irregularity or amenorrhea often occurs among females with bulimia ner- vosa; it is uncertain whether such disturbances are related to weight ﬂuctuations, to nu- tritional deficiencies, or to emotional distress. The fluid and electrolyte disturbances resulting from the purging behavior are sometimes sufficiently severe to constitute med- ically serious problems. Rare but potentially fatal complications include esophageal tears, gastric rupture, and cardiac arrhythmias. Serious cardiac and skeletal myopathies have been reported among individuals following repeated use of syrup of ipecac to induce vom- iting. Individuals who chronically abuse laxatives may become dependent on their use to stimulate bowel movements. Gastrointestinal symptoms are commonly associated with bulimia nervosa, and rectal prolapse has also been reported among individuals with this disorder.
Twelve-month prevalence of bulimia nervosa among young females is 1%—1.5%. Point prevalence is highest among young adults since the disorder peaks in older adolescence and young adulthood. Less is known about the point prevalence of bulimia nervosa in males, but bulimia nervosa is far less common in males than it is in females, with an ap- proximately 10:1 female-to-male ratio.
Bulimia nervosa commonly begins in adolescence or young adulthood. Onset before pu- berty or after age 40 is uncommon. The binge eating frequently begins during or after an episode of dieting to lose weight. Experiencing multiple stressful life events also can pre- cipitate onset of bulimia nervosa.