Last reviewed: 4 Jul 2021
Last updated: 10 Oct 2018



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

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

Risk factors

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

Diagnostic investigations

1st investigations to order

  • CBC
  • 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 research support from the National Institute for Mental Health (NIMH), research support from Eli Lilly & Co (medication only; no support since 2016), and royalties from UpToDate.

B. Timothy Walsh, MD

Professor of Pediatric Pharmacology

Department of Psychiatry

Columbia University

New York



BTW has received royalties from Guilford Press, McGraw-Hill, and UpToDate for authorship.


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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