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

Prevalence
  • 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 or --

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

Prevalence
  • 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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