Anorexia Nervosa

Core concept

Persistent restriction of energy intake leading to significantly low body weight, intense fear of weight gain or persistent behavior interfering with weight gain, and disturbance in self-perceived weight/shape.

Plain-language explanation

Anorexia Nervosa involves three interconnected features: restrictive eating that produces a significantly low body weight for the person's age, sex, and developmental trajectory; an intense fear of gaining weight (or behavior that persistently prevents weight gain even while underweight); and a disturbance in how body weight or shape is experienced or its importance for self-evaluation.

Developmental considerations

Onset commonly occurs in adolescence, though presentations across childhood and adulthood also occur; the condition carries significant medical risk and among the highest mortality rates of any mental health condition, making early recognition especially important.

Functional impact

Medical complications (cardiovascular, endocrine, bone density) and significant psychosocial impairment (withdrawal from social eating situations, preoccupation with food/body) are common; functioning can appear superficially preserved in some domains (e.g., academic achievement) even as physical health deteriorates.

Associated features

Preoccupation with food, calories, and body checking behaviors; social withdrawal, particularly around eating situations; and, in some individuals, co-occurring perfectionism or rigid thinking patterns are frequently observed.

Cultural considerations

Body ideals, the social meaning of thinness, and food-related practices vary substantially across cultures, and presentations may differ in whether an explicit "fear of fatness" is verbally expressed versus other culturally shaped justifications for restriction being given.

Common misconception

A common misconception is that Anorexia Nervosa only affects a particular demographic (for example, only affluent young women) or that it is a "choice" or diet taken too far. It occurs across genders, ages, and backgrounds, and involves serious physiological and psychological processes, not simple willpower around eating.

Reconsider this formulation

If significant weight loss is clearly explained by a diagnosed medical condition, and the person expresses no fear of weight gain or body-image disturbance and is actively distressed by the weight loss itself, an educational case would prompt you to consider a medical cause rather than Anorexia Nervosa.

Example fictional case

Over several months, a student has significantly restricted food intake and lost a substantial amount of weight, insists they still need to lose more despite being underweight by clinical standards, avoids eating with friends, and becomes visibly anxious when discussing food or weight.

References

APA (2022, updated 2024). DSM-5-TR, Feeding and Eating Disorders chapter.

Recognition pattern

Restriction of energy intake relative to requirements leading to a significantly low body weight in context of age/sex/developmental trajectory/physical health, plus either intense fear of gaining weight/becoming fat or persistent behavior interfering with weight gain, plus disturbed body-weight/shape self-perception or persistent lack of recognition of the seriousness of the low body weight.

What to notice

• Restriction of energy intake relative to requirements, leading to significantly low body weight for age/sex/developmental trajectory/physical health
• Intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain, even at a significantly low weight
• Disturbance in the way body weight or shape is experienced, undue influence of body weight/shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight
• Restricting type (no recurrent binge-eating/purging) or binge-eating/purging type
• Severity specified by BMI in adults (mild, moderate, severe, extreme)

Distinguish

Distinguish Anorexia Nervosa from Avoidant/Restrictive Food Intake Disorder by the presence of weight/shape-driven fear and body-image disturbance (present in Anorexia Nervosa, absent in ARFID).

Differential considerations

Low weight due to a medical condition, another mental health condition affecting appetite (such as a depressive episode), or Avoidant/Restrictive Food Intake Disorder (restriction without the characteristic fear of weight gain or body-image disturbance) must be considered before concluding Anorexia Nervosa.

Commonly confused conditions

• Major Depressive Disorder

Related comparisons

Reasoning prompts

• If a case describes low body weight from a diagnosed medical illness, with no fear of weight gain and no body-image disturbance, why does that combination argue against Anorexia Nervosa despite the low weight?

Clarifying questions to ask

• Is there any evidence of body-image or weight/shape-driven motivation behind the restriction?
• What appears to be driving the restriction -- sensory sensitivity, low interest in food, or fear of a specific aversive consequence like choking?
• What is the nutritional/functional impact, and does it meet ARFID's or Anorexia Nervosa's respective severity considerations?
• What is the person's current body weight relative to what is minimally expected for their age, sex, and developmental trajectory?
• Are binge episodes followed by any regular compensatory behavior (purging, fasting, excessive exercise)?
• Is there an intense fear of weight gain or a disturbance in how the person perceives their own body weight or shape?
• How frequently do binge episodes and compensatory behaviors occur, and over what duration?
• Is there an intense fear of weight gain and a disturbance in body-weight/shape self-perception?
• What specific criterion of Anorexia Nervosa is not met here?
• Has Anorexia Nervosa been actively ruled out, rather than simply not yet confirmed?

Case Lab

Practice questions

2 question(s) reference this disorder. Practice Anorexia Nervosa →