Differences Between Bulimia Nervosa and Anorexia Nervosa
The key difference between bulimia nervosa and anorexia nervosa is that bulimia is characterized by recurrent episodes of binge eating followed by compensatory behaviors, while anorexia is defined by severe food restriction leading to significantly low body weight, along with intense fear of weight gain and body image distortion. 1
Core Diagnostic Features
Anorexia Nervosa
- Characterized by restriction of food intake leading to significantly lower than expected body weight 1
- Intense fear of gaining weight or becoming fat, even when underweight 1
- Disturbance in the way one's body weight or shape is experienced 1
- Two subtypes: restricting type and binge-eating/purging type 1
Bulimia Nervosa
- Characterized by recurrent episodes of binge eating (consuming large amounts of food with a sense of lack of control) 1
- Repeated use of inappropriate compensatory behaviors to prevent weight gain (self-induced vomiting, laxative abuse, fasting, or excessive exercise) 1
- Behaviors occur at least once a week for 3 months according to DSM-5 criteria 1
- Self-worth is overly based on body shape and weight 1, 2
- Unlike anorexia, body weight is typically normal or near normal 3
Weight Status and Body Perception
- In anorexia nervosa, patients maintain a body weight below minimally normal levels, while in bulimia nervosa, patients typically maintain a normal or near-normal body weight 2, 3
- Both disorders involve body image disturbances, but anorexia patients often deny their illness while bulimia patients are typically aware of their eating difficulties and feel distressed about them 3
Behavioral Patterns
- Anorexia primarily involves restriction of food intake, though the binge-eating/purging subtype may also include purging behaviors 1
- Bulimia involves a cycle of binge eating followed by compensatory behaviors to prevent weight gain 1
- The key distinction between anorexia nervosa binge-eating/purging subtype and bulimia nervosa is primarily based on weight status 2
Medical Complications
- Anorexia nervosa complications are primarily related to malnutrition and underweight, including hypothermia, bradycardia, hypotension, and other serious health issues 1, 4
- Bulimia nervosa complications are mainly related to purging behaviors, resulting in electrolyte imbalances, acid-base disturbances, and local complications (such as dental erosion and parotid gland enlargement) 4, 5
- Both disorders have high mortality rates compared to other psychiatric disorders, with anorexia having a mortality rate of 4-11%, about 12 times higher than the general population 5, 6
Epidemiology and Onset
- Peak age of onset for anorexia nervosa is early to mid-adolescence 1
- Peak age of onset for bulimia nervosa is late adolescence 1
- Lifetime prevalence in adolescent females: anorexia nervosa (0.3%), bulimia nervosa (0.9%) 1
- Both disorders affect predominantly females, with a female-to-male ratio of approximately 9:1 1
Treatment Approaches
- For anorexia nervosa: focus on weight restoration, normalizing eating behaviors, and addressing psychological aspects like fear of weight gain 7
- For adolescents with anorexia: family-based treatment is recommended when caregivers can be involved 7
- For bulimia nervosa: cognitive-behavioral therapy (CBT) is the first-line treatment, often combined with serotonin reuptake inhibitors (typically fluoxetine) 7, 2
- Both disorders benefit from a multidisciplinary approach involving medical, psychiatric, psychological, and nutritional expertise 7
Early identification and intervention are critical for both disorders to prevent serious complications and improve outcomes related to morbidity, mortality, and quality of life 2, 4.