1. Criteria

Restriction of energy intake leads to significantly low body weight in the context of age, sex, developmental trajectory, and physical health.

There is intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain.

There is disturbance in body-weight or shape experience, undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of low body weight.

Restricting type: during the last 3 months, weight loss has primarily been achieved through dieting, fasting, or excessive exercise, without recurrent binge-eating or purging.
Binge-eating or purging type: during the last 3 months, recurrent binge-eating or purging behavior has been present.

Severity is commonly framed by current body mass index in adults, while remembering that clinical severity also depends on medical instability, rate of weight loss, compensatory behaviors, and functional impairment.

2. Context

Anorexia nervosa is not just low weight. It is a pattern of restriction, fear of weight gain, and body-image distortion that pulls eating, identity, and self-evaluation into a narrow and often dangerous cycle.
Low weight required: Significantly low weight remains part of the core diagnosis, so the syndrome is not defined by thoughts alone.
Psychological drivers: The fear of weight gain and the distorted relationship to body shape help distinguish anorexia from other causes of weight loss.
Subtype thinking: It is still helpful to ask whether the picture is primarily restrictive or whether binge-purge behaviors are also part of it.
Clinical focus: Common self-report eating-disorder symptom measure.

3. Validated scales

EDE-Q

Common self-report eating-disorder symptom measure.

Eating Disorder Examination

Structured interview for diagnostic clarification and symptom severity.

BMI and medical monitoring

Not a psychiatric scale, but essential for severity and medical risk framing.

4. FDA approved treatments

Diagnosis-specific FDA indications

This prototype does not list a core anorexia-nervosa-specific FDA medication indication; treatment is centered on nutritional rehabilitation, psychotherapy, and medical stabilization. Verify current labeling for any symptom-targeted use.

No diagnosis-specific FDA medication entry is listed in this prototype section.

Common treatment side effects

Check drugs.com/sfx for common side effects. Direct side-effect links for the medications in this section are below when available.

Common off-label medications

Interventional psychiatry modalities

ECT may be considered in severe comorbid depression or life-threatening psychiatric deterioration.
Ketamine is not a standard anorexia treatment and remains investigational.
TMS is under study but not established for anorexia nervosa.

Related Guides

5. Top management articles

Management review for Anorexia Nervosa PubMed search
Anorexia Nervosa treatment guideline PubMed search
Anorexia Nervosa pharmacotherapy or psychotherapy review PubMed search

When to seek professional help

Seek urgent help if there are thoughts of suicide, self-harm, or feeling unable to stay safe.³
Seek urgent help if there are thoughts of harming someone else, escalating violent urges, or loss of behavioral control.³
Take hopelessness seriously, especially if the person feels trapped, cannot imagine staying safe, or is withdrawing from support.⁴
Use emergency services if there is immediate danger, severe agitation, psychosis, intoxication, or inability to care for basic needs. In the United States, call or text 988 for crisis support and call 911 for immediate danger. Use emergency services in your region if you are outside the U.S.³

Simple Psych

Anorexia Nervosa