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Anorexia nervosa

Last reviewed: 6 Nov 2023
Last updated: 31 Mar 2023



History and exam

Key diagnostic factors

  • significantly low body weight
  • fear of gaining weight or becoming fat, or behaviors that interfere with weight gain despite evidence of significantly low body weight
  • disturbed body image
  • calorie restriction
  • binge-eating and/or purging
  • misuse of laxatives, diuretics, or diet pills
  • amenorrhea
  • decreased subcutaneous fat
More key diagnostic factors

Other diagnostic factors

  • general fatigue, weakness, and poor concentration
  • significant preoccupation with thoughts of food
  • orthostatic hypotension
  • nonspecific gastrointestinal symptoms
  • cardiac symptoms and signs
  • changes to hair, skin, and nails
  • dependent edema
  • osteopenia or osteoporosis
Other diagnostic factors

Risk factors

  • female sex
  • adolescence and puberty
  • obsessive and perfectionist traits
  • exposure to Western media
  • genetic influence
  • middle and upper socioeconomic classes
More risk factors

Diagnostic investigations

1st investigations to order

  • CBC
  • serum chemistry
  • thyroid function tests
  • liver function tests
  • urinalysis
More 1st investigations to order

Investigations to consider

  • ECG
  • bone densitometry (dual-energy x-ray absorptiometry)
  • estradiol in females
  • testosterone in males
More investigations to consider

Treatment algorithm


medically stable and suitable for outpatient treatment

medically unstable or outpatient failure



Evelyn Attia, MD

Professor of Psychiatry

Columbia University and Weill Cornell Medical College

New York



EA is a board member of a not-for-profit religious organization, a research advisory board member of National Eating Disorders Association (NEDA), a not-for-profit advocacy organization and a clinical advisor to Equip Health, a for-profit entity that offers telehealth treatment for eating disorders to adolescents.She does not receive payments for the above. She receives research support from the National Institute for Mental Health (NIMH); no conflict. She is involved in no contract research at present, is expecting to begin a contract with COMPASS Pathways to support a multi-site study of psilocybin for anorexia nervosa. She regularly lectures and educates on the subject of eating disorders but does not receive payment for these activities. She receives royalties from UpToDate for written sections. She has stock options from Equip Health.

B. Timothy Walsh, MD

Professor of Psychiatry

Columbia University

New York



BTW has received royalties from Guilford Press, McGraw-Hill, Oxford University Press, the British Medical Journal, Johns Hopkins University Press, and UpToDate for authorship, and from Guidepoint Global for consultation.


Professor Evelyn Attia and Professor B. Timothy Walsh would like to gratefully acknowledge Dr Pauline S. Powers and Dr Abby M. Irwin, previous contributors to this topic.


PSP and AMI declare that they have no competing interests.

Peer reviewers

Heather Thompson-Brenner, MD


Eating Disorders Program Center for Anxiety and Related Disorders

Psychology Department

Boston University




HTB declares that she has no competing interests.

  • Anorexia nervosa images
  • Differentials

    • Bulimia nervosa
    • Avoidant-restrictive food intake disorder (ARFID)
    • Depression
    More Differentials
  • Guidelines

    • Practice guideline for the treatment of patients with eating disorders
    • Guidelines for the management of eating disorders
    More Guidelines
  • Patient leaflets


    Anorexia: questions to ask your doctor

    More Patient leaflets
  • Calculators

    Body Mass Index (BMI) percentiles for boys (2 to 20 years)

    Body Mass Index (BMI) percentiles for girls (2 to 20 years)

    More Calculators
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