Today we will continue our current theme of eating disorders. Today's topic is anorexia nervosa. In part 1 we will cover an introduction, definitions, diagnostic criteria, epidemiology, and pathogenesis. In part 2 we will cover clinical pearls, physical complications, and treatment.
Today's Content Level: Beginner and Intermediate
Anorexia nervosa (AN) is an eating disorder characterized by significantly low body weight and preoccupation with weight, body image, and being thin.
It involves an intense fear of gaining weight or behaviors that prevent weight gain such as restricting calories, excessive exercise, self-induced vomiting, using laxatives, and more.
The term, anorexia nervosa, comes from the Greek term for "loss of appetite" and a Latin word implying "nervous origin".
The authors of Kaplan and Sadock's describe AN as a syndrome of three essential criteria: The first is a self-induced starvation to a significant degree— a behavior. The second is a relentless drive for thinness or a morbid fear of fatness— a psychopathology. The third criterion is the presence of medical signs and symptoms resulting from starvation— a physiological symptomatology.
Diagnostic Criteria 2
Restriction of caloric intake relative to requirements.
Significantly low body weight (less than minimally normal in the context of age, sex, developmental trajectory, and physical health).
Intense fear of gaining weight or becoming fat OR persistent behaviors that prevent weight gain.
Disturbed body image OR undue influence of body weight/shape on self-evaluation OR lack of recognition of the seriousness of current low body weight.
Two main sub-types-> 1) Restricting type: Weight loss is achieved through restricting calories, fasting, and/or excessive exercise. Has not regularly engaged in binge-eating or purging behavior. 2) Binge-eating/purging type: Engages in eating binges followed by self-induced vomiting, and/or using laxatives, enemas, or diuretics. Some individuals purge after eating small amounts of food without binging.
Severity is specified based on BMI for adults and BMI percentile for children and adolescents. Mild = BMI ≥17. Moderate = BMI 16-16.99. Severe = BMI 15-15.99. Extreme = BMI <15. The level of severity may be increased to reflect clinical symptoms, degree of functional disability, or the need for supervision.
Lifetime prevalence of AN is 1% in females (studies vary: 0.5-4%) and <0.5% in men (studies vary: (0.1-1.3%). 12-month prevalence among young females is 0.4%.
As many as 5% of young women exhibit symptoms of anorexia but do not meet the full diagnostic criteria, and some studies show disordered eating behavior in 15% of adolescent girls in the United States.
Studies reflect approximately a 10:1 female to male ratio. Sex distribution is less skewed in children.
Most common age of onset is between 14-18 years old but can occur at any age. Some studies show peaks at 13-14 and 17-18 which is hypothesized to occur due to hormonal and environmental influences respectively.
Tends to be a chronic and relapsing illness, however the course is variable. Approximately 50% experience remission. Time to remission is 5-6 years.
AN has the highest mortality among psychiatric disorders. This is due to high rates of suicide (1 in 5 deaths occur by suicide) and medical complications such as cardiac or infectious causes.
As with most psychiatric disorders, the dominant theory suggests AN develops from a combination of genetic, biological, environmental, and psychosocial factors.
Risk factors include family history of eating disorders (strong genetic concordance), female gender, age (teenage years higher risk), neglect/abuse/trauma, living in industrialized countries (food is abundant and high social pressure to be thin), poor body image / low self-esteem, adverse perinatal and neonatal events, feeding or sleeping difficulties during infancy, and participation in sports or activities with an emphasis on weight/size or involve subjective judging and weight classes (gymnastics, ballet, modeling, running, cheerleading, figure skating, wrestling, etc.). Genetic correlations have been made between schizoaffective disorder and obsessive-compulsive disorder.
Certain psychodynamic theories and personality traits have also been associated: obsessive-compulsive personality traits, narcissism, difficulty with separation and autonomy, exaggerated values of control, achievement, and perfectionism.
Next lesson we will continue part 2 of anorexia nervosa as we discuss clinical pearls, physical complications, and treatment. If you want more learning resources then check out our recommended resources page.
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