Anorexia nervosa

Anorexia nervosa carries serious and sometimes life-threatening medical risk, so case questions turn on recognizing it and putting medical stability and weight restoration first.

Criteria at exam depth (paraphrased):

• Restriction of energy intake relative to needs, leading to significantly low body weight for age, sex, developmental trajectory, and physical health.
• Intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain, even while underweight.
• Disturbed experience of body weight or shape, undue influence of weight or shape on self-evaluation, or persistent lack of recognition of how serious the low weight is.
• Amenorrhea is not required.
• Subtypes (based on the last 3 months): restricting type (weight loss through dieting, fasting, or excessive exercise, without recurrent bingeing or purging) and binge-eating/purging type.
• Severity in adults by BMI: mild 17 or above, moderate 16–16.99, severe 15–15.99, extreme below 15. Children and adolescents use BMI percentiles.
• Remission specifiers: partial and full.

Hinge differentials:

• ARFID — restriction without fear of weight gain or body-image disturbance.
• Bulimia nervosa — binge and compensatory behavior at a normal or above-normal weight; if significantly low weight, the diagnosis is anorexia, binge-eating/purging type.
• Major depression — appetite and weight loss without fear of gaining weight.
• Medical causes — GI disease, hyperthyroidism, cancer, and other conditions causing weight loss.
• OCD or body dysmorphic disorder — obsessions or appearance concerns not centered on weight and food.

On the NCMHCE: Medical stability drives the level of care: refer for medical evaluation (vital signs, labs, electrolytes, cardiac status), and recognize that unstable vitals, rapid weight loss, or refusal of all food warrant a higher level of care. Screen for suicide risk, which is elevated. Treatment is team-based (medical provider, dietitian, therapist). Family-based treatment is first-line for adolescents; enhanced CBT is used for adults. The treatment plan sets weight restoration benchmarks alongside psychological goals, because starvation reduces cognitive flexibility and limits insight-oriented work. When a client wants to work only on anxiety, validate and integrate it as a co-occurring goal without dropping nutritional rehabilitation. Expect ambivalence; motivational approaches help engagement. Watch for cultural and occupational pressures (dance, athletics, modeling) and recognize that anorexia occurs across genders and body types.

Clinical Pearl: Low weight plus fear of gain or body-image disturbance defines anorexia. Medical stability and weight restoration come before insight work.