Bulimia nervosa is an eating disorder characterized by recurrent binge eating episodes, inappropriate weight compensatory behaviors, and sense of self-worth disproportionately impacted by body weight and/or shape. Causes are multifactorial and similar to those of anorexia nervosa (e.g., genetic factors, psychiatric disorders, psychosocial factors); bulimia nervosa is associated with obesity. It is important to assess for malnutrition severity in affected individuals, regardless of body weight or body mass index (BMI). The diagnosis is confirmed if individuals fulfill all of the DSM-5 diagnostic criteria for bulimia nervosa. Individuals should be evaluated for associated complications (e.g., electrolyte abnormalities) and underlying conditions that may affect weight or cause a change in eating behaviors (e.g., thyroid disorder). Outpatient management is preferred, but hospitalization is indicated if red flags in eating disorders are present. All individuals should be referred for psychotherapy and nutritional management. Pharmacotherapy with fluoxetine may be considered as adjunctive therapy to help decrease binge eating and compensatory behaviors; other SSRIs may also be used to manage comorbid psychiatric conditions (e.g., depression).
- Women: 0.3%–1%
- Men: 0.1%
- Peak age: 20–24 years of age
- Sex: ♀ > ♂ (> 90% of affected individuals are young women)
Epidemiological data refers to the US, unless otherwise specified.
- Etiology is not entirely understood
- See “Etiology of Anorexia nervosa” for factors common to both eating disorders.
- Obesity during childhood and early puberty
Characteristic clinical features
- Recurrent binge eating episodes associated with inappropriate weight compensatory behaviors
- See DSM-5 diagnostic criteria for bulimia nervosa for further detail.
BMI: can be normal or slightly elevated
- > 20 years of age: ≥ 18.5 kg/m2
- ≤ 20 years of age: BMI ≥ 5th percentile for sex and age
|Associated features of bulimia nervosa |
|Central nervous system|
|Gastrointestinal tract|| |
Recurrent purging can lead to severe complications such as esophageal tears, cardiac arrhythmias, and seizures. 
Bulimia nervosa is associated with an increased risk of suicide. 
General principles 
- See “Screening for eating disorders” for indications and screening modalities.
- Determine if individuals fulfill all of the DSM-5 diagnostic criteria for bulimia nervosa to confirm the diagnosis.
- Evaluate for complications and comorbidities, and rule out possible organic etiologies for change in weight and/or eating behaviors: See “Initial evaluation for a suspected eating disorder.”
DSM-5 diagnostic criteria 
|DSM-5 diagnostic criteria for bulimia nervosa |
|All criteria must be fulfilled.|
Binge eating episodes can occur during periods of stress or boredom, or after an attempt to lower body weight through dietary restriction. 
Severity (according to DSM-5) 
Based on the number of episodes of inappropriate weight compensatory behaviors per week.
- Mild: 1–3 episodes/week
- Moderate: 4–7 episodes/week
- Severe: 8–13 episodes/week
- Extreme: ≥ 14 episodes/week
Laboratory studies 
- ↓ Potassium, ↓ sodium, ↓ chloride, and ↓ calcium
- Metabolic alkalosis
- Possible ↑ serum α-amylase
- See also “Characteristic laboratory abnormalities in eating disorders” for additional studies and findings.
- Binge eating disorder
- Anorexia nervosa, binge eating/purging type
- Major depressive disorder with atypical features
The differential diagnoses listed here are not exhaustive.
General principles 
- Evaluate for red flag features of eating disorders.
- Determine appropriate care setting; see “Disposition for eating disorders.”
- Discuss treatment goals, e.g.: 
- Decrease the number of episodes of inappropriate weight compensatory behaviors.
- Improve disordered thoughts and beliefs (e.g., about body image, self-esteem, eating behaviors).
- Identify and manage complications: See “Clinical features”, and “Laboratory studies” in “Diagnostics.”
- Comanage nutritional management with a dietitian.
- Provide nutritional education.
- Promote healthy eating habits.
Refer all patients for psychotherapy; consider pharmacotherapy only as adjunctive therapy.
- Preferred initial management in adults: cognitive behavioral therapy with or without an SSRI (fluoxetine)
- Preferred initial management in adolescents and young adults: family-based therapy with an involved caregiver
- Regularly reassess for remission. 
- Partial remission : some (not all) criteria for bulimia nervosa are met for a sustained period of time
- Full remission : none of the criteria for bulimia nervosa are met for a sustained period of time
Nutritional management 
- Evaluate nutritional intake.
- Educate and support patients to implement healthy eating habits, including binge eating prevention strategies.
- For underweight patients, guidance in weight restoration for AN may be appropriate. 
First-line therapy for bulimia nervosa
Adolescents and young adults
- Family-based therapy with an involved caregiver (preferred)
- Cognitive behavioral therapy
- Guided self-help programs
- Cognitive behavioral therapy (preferred) 
- Psychodynamic psychotherapy
- Interpersonal therapy
- Guided self-help programs
If a guided self-help approach is used, a lack of improvement within 4 weeks of initiation should prompt referral to an eating disorder specialist. 
Adults: may consider either of the following 
- Initial combination treatment of pharmacotherapy and psychotherapy
- Addition of pharmacotherapy after a 6-week trial of psychotherapy alone (if there is minimal or no response)
- Adolescents: less evidence for use, but may be considered (off-label)
- All patients: management of co-occurring psychiatric conditions (e.g., depression, obsessive compulsive disorder)
Pharmacotherapy should be used only as an adjunct to psychotherapy in the management of bulimia nervosa. 
- Preferred pharmacotherapy agent for bulimia nervosa
- Can reduce binge eating episodes and purging
- Other SSRIs
The antidepressant bupropion lowers the seizure threshold and is contraindicated in individuals with a history of anorexia nervosa, bulimia nervosa, or purging behaviors. 
There is an increased risk of QTc prolongation with high doses of citalopram and escitalopram. 
If patients do not experience symptom improvement with pharmacotherapy, determine whether the medication is being taken shortly before episodes of vomiting. 
See “Complications of eating disorders.”
We list the most important complications. The selection is not exhaustive.
- Course: chronic with relapses 
- Mortality: 2–6 times higher than the general population 
Increased risk of psychological comorbidities 
- Most common: depression, anxiety, and panic disorders (particularly social phobias)
- Attention deficit hyperactivity disorder
- Alcohol and drug addiction or abuse
Bulimia nervosa can transition to anorexia nervosa and vice versa.