anorexia nervosa

Last edited 11/2020 and last reviewed 08/2022

Anorexia nervosa is a psychophysiologic condition, occurring especially in girls and young women, that is characterised by the inability or refusal to eat.

It is a condition of Western Societies.

The prevalence rate of this condition is estimated at 1 to 2% of schoolgirls and female students in higher education. The male prevalence rate is much lower than this. The condition usually has an onset in females between the ages of 16 and 17 years - it is unusual for anorexia nervosa to start after the age of 30.

Anorexia nervosa

  • is an eating disorder characterized by an intense fear of gaining weight and the refusal to maintain a minimally normal body weight
  • individuals with anorexia also exhibit a misperception of body shape and/or size
  • comparing DSM-IV and DMS-5 criteria for anorexia nervosa
    • in DSM-IV, a diagnosis of anorexia nervosa was excluded if the patient maintained bodyweight at or above the 85th percentile for his or her height/age
      • in DSM-5 this criterion is similar, but adds sex, developmental norms, and physical health and uses body mass index data
    • DSM-5 adds “persistent behavior that interferes with weight gain” as an added way to meet a criterion
    • DSM-5 does not include criteria on menstruating females’ absence of three consecutive menses, as previously was ub DSM-IV
    • restrictive type and binge-eating/purging types differ in that DSM-IV specifies “during the current episode” and DSM-5 specifies “during the past 3 months.”
    • DSM-5 adds criteria for partial and full remission, while the DSM-IV does not include this information
    • a study compared 215 youth 8 to 21 years enrolled as new patients with eating disorders in clinic settings and showed an increase from 30 percent to 40 percent in anorexia nervosa when comparing DSM-IV and DSM-5 criteria

A. Restriction of energy intake relative to requirements, leading to a significant low body weight in the context of the age, sex, developmental trajectory, and physical health (less than minimally normal/expected)

  • severity is based on body mass index (BMI) derived from World Health Organization categories for thinness in adults; corresponding percentiles should be used for children and adolescents:
    • Mild: BMI greater than or equal to 17 kg/m2,
    • Moderate: BMI 16–16.99 kg/m2,
    • Severe: BMI 15–15.99 kg/m2,
    • Extreme: BMI less than 15 kg/m2

B. Intense fear of gaining weight or becoming fat or persistent behavior that interferes with weight gain.

C. Disturbed by one’s body weight or shape, self-worth influenced by body weight or shape, or persistent lack of recognition of seriousness of low bodyweight.

**Dropped from DSM-IV D. In menstruating females, absence of at least 3 consecutive non-synthetically induced menstrual cycles.

Restricting type:

  • During the last 3 months, the individual has not engaged in recurrent episodes of binge eating or purging behaviour (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas). This subtype describes presentations in which weight loss is accomplished primarily through dieting, fasting, and/or excessive exercise
  • (previously in DSM-IV "During current episode..")

Binge-eating/purging type:

  • During the last 3 months, the individual has engaged in recurrent episodes of binge eating or purging behaviour (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas)
  • (previously in DSM-IV "During current episode..")

Added criteria for "full remission" and "partial remission"

Partial remission: After full criteria met, low bodyweight has not been met for sustained period, BUT at least one of the following two criteria still met:

  • Intense fear of gaining weight/becoming obese or behavior that interferes with weight gain
  • OR
  • Disturbed by weight and shape.

Full remission: After full criteria met, none of the criteria met for sustained period of time.