Anorexia Nervosa
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Basics
Description
- An eating disorder characterized by the restriction of food intake leading to significantly low weight (less than minimally normal/expected) in the context of age, sex, developmental trajectory, and physical health, with intense fear of weight gain and body image disturbance.
- 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 for last 3 months
- Binge eating/purging type: regularly engages in binge eating or purging behaviors (last 3 months)
- System(s) affected: cardiovascular, endocrine, metabolic, gastrointestinal, nervous, reproductive
- Severity of anorexia nervosa (AN) is based on body mass index (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
Epidemiology
- Predominant age: 13 to 20 years
- Predominant sex: female > male (10:1 female-to-male ratio)
Incidence
8 to 19 women/2 men per 100,000 per year
- 0.9% in women (0.3% in young females)
- 0.3% in men (higher in gay and bisexual men)
Etiology and Pathophysiology
- Complex relationship among genetic, biologic, environmental, psychological, and social factors that result in the development of this disorder
- Subsequent malnutrition may lead to multiorgan damage.
- Serotonin, norepinephrine, and dopamine neuronal systems are implicated.
Genetics
- There is 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
Risk Factors
- Female gender
- Adolescence
- Body dissatisfaction
- Perfectionism
- Negative self-evaluation
- Academic pressure
- Severe life stressors
- Participation in sports or artistic activities that emphasize leanness or involve subjective scoring: ballet, running, wrestling, figure skating, gymnastics, cheerleading, weight lifting
- Type 1 diabetes mellitus
- Family history of substance abuse, affective disorders, or eating disorder
General Prevention
Prevention programs can reduce risk factors and future onset of eating disorders.
- Target adolescents and young women 15 years of age or older.
- 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
- Mood disorder—major depressive disorder
- Anxiety disorders—social phobia, obsessive-compulsive disorder, posttraumatic stress disorder
- Substance use disorder
- High rates of cluster C personality disorders
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
- An eating disorder characterized by the restriction of food intake leading to significantly low weight (less than minimally normal/expected) in the context of age, sex, developmental trajectory, and physical health, with intense fear of weight gain and body image disturbance.
- 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 for last 3 months
- Binge eating/purging type: regularly engages in binge eating or purging behaviors (last 3 months)
- System(s) affected: cardiovascular, endocrine, metabolic, gastrointestinal, nervous, reproductive
- Severity of anorexia nervosa (AN) is based on body mass index (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
Epidemiology
- Predominant age: 13 to 20 years
- Predominant sex: female > male (10:1 female-to-male ratio)
Incidence
8 to 19 women/2 men per 100,000 per year
- 0.9% in women (0.3% in young females)
- 0.3% in men (higher in gay and bisexual men)
Etiology and Pathophysiology
- Complex relationship among genetic, biologic, environmental, psychological, and social factors that result in the development of this disorder
- Subsequent malnutrition may lead to multiorgan damage.
- Serotonin, norepinephrine, and dopamine neuronal systems are implicated.
Genetics
- There is 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
Risk Factors
- Female gender
- Adolescence
- Body dissatisfaction
- Perfectionism
- Negative self-evaluation
- Academic pressure
- Severe life stressors
- Participation in sports or artistic activities that emphasize leanness or involve subjective scoring: ballet, running, wrestling, figure skating, gymnastics, cheerleading, weight lifting
- Type 1 diabetes mellitus
- Family history of substance abuse, affective disorders, or eating disorder
General Prevention
Prevention programs can reduce risk factors and future onset of eating disorders.
- Target adolescents and young women 15 years of age or older.
- 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
- Mood disorder—major depressive disorder
- Anxiety disorders—social phobia, obsessive-compulsive disorder, posttraumatic stress disorder
- Substance use disorder
- High rates of cluster C personality disorders
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