- An eating disorder characterized by the restriction of food intake leading to significantly low weight with intense fear of weight gain
- Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), divides anorexia into two types:
- Restricting type: not engaged in binge eating or purging behaviors (last 3 months)
- Binge eating/purging type: regularly engaged in binge eating or purging behaviors (last 3 months)
- System(s) affected: nervous, cardiovascular, endocrine, metabolic, pulmonary, gastrointestinal, reproductive, ophthalmic, taste, and dermatologic
- Severity of anorexia nervosa (AN) is based on BMI (per DSM-5):
- Mild: BMI ≥17 kg/m2
- Moderate: BMI 16.00 to 16.99 kg/m2
- Severe: BMI 15.00 to 15.99 kg/m2
- Extreme: BMI <15 kg/m2
- Predominant age: 15 to 24 years
- Predominant sex: female > male (10:1 to 20:1 female-to-male ratio)
- 0.9–2.0% in women (1.1–3.0% in young females)
- 0.1–0.3% in men (higher in gay and bisexual men)
Etiology and Pathophysiology
- Complex relationships among genetic, biologic, environmental, psychological, and social factors that result in the development of this disorder
- Parenting style that leads to high expectation may result in children struggle for control.
- Serotonin, norepinephrine, and dopamine neuronal systems are implicated.
- Evidence of higher concordance rates in monozygotic than in dizygotic twins
- First-degree female relative with eating disorder increases risk 6- to 10-fold.
- One genome-wide significant locus identified for AN on chromosome 12
- Female gender
- Body dissatisfaction, negative self-evaluation
- Perfectionism, high parental demands, academic pressure, severe life stressors
- History of sexual or physical abuse
- Participation in sports or activities that emphasize leanness: ballet, figure skating, gymnastics, cheerleading
- Type 1 diabetes mellitus
- Family history of substance abuse, affective disorders, or eating disorders
Prevention programs can reduce risk factors and future onset of eating disorders.
- Target adolescents and young women ≥15 years of age.
- Encourage realistic and healthy weight management strategies and attitudes.
- Promote self-esteem.
- Reduce focus on thin as ideal.
- Decrease co-occurring anxiety/depressive symptoms and improve stress management.
Commonly Associated Conditions
- Suicide, mood and anxiety disorders
- Substance use disorder
- Cluster C personality disorder
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