Last reviewed: 28 Oct 2021
Last updated: 02 Sep 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • significantly low body weight
  • fear of gaining weight or becoming fat, or behaviours 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
  • amenorrhoea
  • decreased subcutaneous fat

Other diagnostic factors

  • general fatigue, weakness, and poor concentration
  • significant preoccupation with thoughts of food
  • orthostatic hypotension
  • non-specific gastrointestinal symptoms
  • cardiac symptoms and signs
  • changes to hair, skin, and nails
  • dependent oedema
  • osteopenia or osteoporosis

Risk factors

  • female sex
  • adolescence and puberty
  • obsessive and perfectionist traits
  • exposure to Western media
  • genetic influence
  • middle and upper socio-economic classes

Diagnostic investigations

1st investigations to order

  • FBC
  • serum chemistry
  • thyroid function tests
  • liver function tests
  • urinalysis

Investigations to consider

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

Treatment algorithm



Evelyn Attia, MD

Professor of Psychiatry

Columbia University and Weill Cornell Medical College

New York



EA receives royalties from UpToDate for authorship.

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.

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