Feeding and eating disorders are persistent disturbances of eating or eating-related behavior that impair physical health or psychosocial functioning. They have the highest mortality of any psychiatric illness group, from medical complications and suicide. Causes combine genetic vulnerability, neurobiology (serotonin and reward pathways), personality traits (perfectionism, anxiety, impulsivity), family and sociocultural pressure toward thinness, dieting, trauma, and athletic or occupational weight demands. They occur in all sexes, body sizes, ages, and ethnic groups; a person can be medically unstable at a normal or high weight.
DSM-5-TR disorders
| Disorder | Key features |
|---|
| Anorexia nervosa (AN) | Restriction of intake leading to significantly low body weight for age, sex, and development; intense fear of weight gain or persistent behavior that prevents gain; disturbed body image or lack of recognition of the seriousness of low weight. Subtypes: restricting and binge-eating/purging. Amenorrhea is no longer a criterion, and there is no fixed "85% of expected weight" cutoff |
| Bulimia nervosa (BN) | Recurrent binge eating with inappropriate compensatory behavior (self-induced vomiting, laxatives, diuretics, enemas, fasting, excessive exercise), both at least once a week for 3 months; self-evaluation unduly influenced by shape and weight; weight usually normal or above |
| Binge-eating disorder (BED) | Recurrent binges at least once a week for 3 months with loss of control and marked distress, without regular compensatory behavior; eating rapidly, until uncomfortably full, when not hungry, alone because of embarrassment, and feeling disgusted or guilty afterward. Most common eating disorder |
| Avoidant/restrictive food intake disorder (ARFID) | Avoidance or restriction due to sensory characteristics of food, fear of choking or vomiting, or lack of interest — without body image disturbance |
| Pica | Persistent eating of nonfood substances (dirt, clay, ice, paint chips, hair) for at least 1 month, inappropriate for developmental level; linked with iron deficiency, pregnancy, and intellectual disability; risks lead poisoning and bowel obstruction |
| Rumination disorder | Repeated regurgitation, rechewing, or spitting out of food for at least 1 month |
| Other specified feeding or eating disorder (OSFED) | For example, atypical anorexia nervosa: all AN criteria except low weight (weight is in or above the normal range despite major loss) — same medical risks, including refeeding syndrome |
Severity (DSM-5-TR)
- AN (adults, by BMI): mild 17 or higher, moderate 16–16.99, severe 15–15.99, extreme under 15 kg/m²; children and adolescents use BMI percentile or percent of median BMI
- BN: mild 1–3, moderate 4–7, severe 8–13, extreme 14 or more compensatory episodes per week
- BED: mild 1–3, moderate 4–7, severe 8–13, extreme 14 or more binges per week
Anorexia nervosa — starvation effects
- Bradycardia, hypotension, orthostatic changes, hypothermia, cold intolerance
- Lanugo, dry skin, brittle hair and nails, acrocyanosis
- Amenorrhea, constipation, delayed gastric emptying
- Hypoglycemia, low bone density (osteopenia, osteoporosis), anemia, leukopenia
- Denial of illness, preoccupation with food, rituals, excessive exercise, social withdrawal
Bulimia nervosa — purging effects
- Dental enamel erosion, parotid (salivary) gland enlargement, Russell sign (calluses on knuckles)
- Hypokalemia, hypochloremic metabolic alkalosis from vomiting; metabolic acidosis from laxative abuse
- Esophagitis, Mallory–Weiss tears, rarely esophageal rupture
- Dysrhythmias from hypokalemia; dehydration
Binge-eating disorder — weight gain, type 2 diabetes, hypertension; shame, depression. Assess the emotional states and situations that trigger bingeing.
Psychosocial: body image distortion, low self-esteem, perfectionism, depression, anxiety, obsessive-compulsive traits, self-harm, suicide risk, substance use.
| Test | Findings/purpose |
|---|
| Weight, height, BMI (or BMI percentile/percent median BMI in youth) | Blinded weights if helpful; same scale, gown after voiding |
| Vital signs with orthostatics, temperature | Bradycardia, hypotension, hypothermia |
| Electrolytes (potassium, phosphate, magnesium), glucose, BUN/creatinine | Hypokalemia with purging; low phosphate and magnesium at risk of refeeding |
| ECG | Bradycardia, prolonged QTc, dysrhythmias |
| CBC, liver tests, amylase | Cytopenias, elevated liver enzymes, elevated amylase with vomiting |
| Bone density (DXA) | After about 6 months of amenorrhea or low weight |
| Screening tools (SCOFF, Eating Disorder Examination Questionnaire) | Screening and severity |
Indications for hospitalization — thresholds differ between guidelines and age groups; follow local protocol.
| Group | Examples of admission criteria |
|---|
| Adults (APA 2023) | Bradycardia under 40/min or tachycardia over 110/min; marked orthostatic change (pulse rise of 20/min or more, or standing blood pressure drop of 20 mmHg or more); inability to maintain core body temperature. Some adult protocols use a higher heart rate cutoff (under 50/min) |
| Adolescents and young adults (SAHM 2022) | Heart rate under 50/min awake or under 45/min asleep; systolic blood pressure under 90 mmHg or under 90/45 mmHg; temperature under 35.6 °C (96 °F); marked orthostatic change; under 75% of median BMI |
| Any age | Severe hypokalemia (commonly under 3.0 mmol/L), hypophosphatemia, or hypoglycemia (commonly under 60 mg/dL, 3.3 mmol/L); dysrhythmia or prolonged QTc; very low weight; acute food refusal; failure of outpatient care; suicide risk |
Priority in anorexia: stabilize life-threatening medical problems first, then restore weight and address psychological issues.
Nutritional rehabilitation and refeeding syndrome
- Refeeding syndrome: when nutrition restarts after starvation, insulin release drives phosphate, potassium, and magnesium into cells, causing hypophosphatemia, hypokalemia, hypomagnesemia, fluid retention, and thiamine deficiency. Consequences: heart failure, dysrhythmias, respiratory failure, rhabdomyolysis, seizures, delirium, and death. Onset usually within the first 5 days of refeeding.
- High-risk adults (general criteria): very low BMI, significant recent weight loss, little or no intake for several days, or low potassium, phosphate, or magnesium before feeding.
- Adult consensus (ASPEN 2020) for high-risk clients: start about 10–20 kcal/kg/day (or 100–150 g dextrose), then advance by about 33% of the goal every 1–2 days; give thiamine 100 mg before feeding and daily for 5–7 days; check phosphate, potassium, and magnesium at baseline and frequently during the first days (commonly every 12 hours for 3 days in high-risk clients), replacing as needed. Specialized eating disorder programs may use faster, closely monitored refeeding in adolescents.
- Oral intake is preferred; nasogastric feeding if oral intake fails or in life-threatening malnutrition.
Psychotherapy
- Family-based treatment (FBT) — first-line for adolescents with AN or BN; parents temporarily take charge of meals
- CBT and enhanced CBT (CBT-E) — first-line for BN and BED; used in adult AN
- Interpersonal therapy, DBT for emotion dysregulation
Pharmacotherapy
| Drug | Use | Safety points |
|---|
| Fluoxetine (higher dose, commonly 60 mg) | Bulimia nervosa (FDA-approved) | Boxed warning for suicidality under 25; GI upset, insomnia, sexual dysfunction; serotonin syndrome risk |
| Lisdexamfetamine | Moderate to severe BED in adults (FDA-approved) | Schedule II — boxed warning for abuse, misuse, and addiction; raises heart rate and blood pressure; insomnia, decreased appetite; not for weight loss |
| Olanzapine (off-label) | Sometimes used in AN for anxiety and weight gain | Metabolic effects, sedation; QT caution |
| Bupropion | Contraindicated in bulimia and anorexia | Seizure risk with electrolyte imbalance |
No medication restores weight in AN by itself.
Listed in priority order.
- Physiologic stability
- Vital signs including orthostatics, cardiac monitoring as ordered, daily electrolytes during early refeeding
- Watch for refeeding syndrome: edema, dyspnea, crackles, tachycardia, dysrhythmias, weakness, confusion, seizures
- Suicide and self-harm assessment — ask directly; eating disorders carry high suicide risk
- Nutrition and weight restoration
- Start with small, frequent meals and increase gradually, following the dietitian plan
- Supervise meals and set a time limit (commonly 30 minutes); observe for 1–2 hours after meals (bathroom access supervised) to prevent purging
- Weigh at the same time daily or as ordered, after voiding, in a gown, with the back to the scale if the program uses blinded weights; check for hidden weights or water loading
- Monitor intake and output and excessive exercise
- Use a behavioral contract with privileges linked to weight and health goals, not punishment
- Therapeutic relationship and communication
- Listen with acceptance; be consistent and nonjudgmental
- Focus on feelings, not on food and weight: "I'd like to understand how you came to think this way about your weight."
- Do not argue or bargain about food; avoid comments on appearance
- Explore emotions, body image, and triggers for bingeing or purging; help the client identify emotional states that precede binges and plan other coping
- Body image and self-esteem — help the client identify strengths not related to weight; challenge cognitive distortions (all-or-nothing thinking)
- Family involvement — family therapy, education, consistent support
- Eating disorders are serious medical illnesses, not a choice; recovery is possible with treatment
- Explain why weight restoration is gradual and why labs are checked often at first
- Purging (vomiting, laxatives, diuretics) causes dangerous potassium loss and heart rhythm problems; report palpitations, weakness, or fainting
- After vomiting, rinse the mouth with water or a baking soda solution instead of brushing immediately; see a dentist regularly
- Take calcium and vitamin D as prescribed for bone health; weight-bearing activity only as approved
- Family: support without force — do not force-feed or punish; avoid talking about diets, weight, or appearance at home; model regular balanced meals; follow the treatment team's meal plan
- Relapse warning signs: skipping meals, rigid food rules, secret eating, excessive exercise, frequent weighing
| Complication | What to watch for |
|---|
| Refeeding syndrome | Low phosphate, potassium, magnesium; edema, heart failure, dysrhythmias, confusion, seizures in the first days of feeding |
| Cardiac dysrhythmias / sudden death | Bradycardia, prolonged QTc, hypokalemia |
| Severe hypokalemia | Weakness, cramps, ECG changes |
| Suicide | Hopelessness, self-harm |
| Hypoglycemia | Confusion, sweating, seizures |
| Esophageal rupture | Severe chest pain after vomiting |
| Osteoporosis and fractures | Long-term low weight, amenorrhea |
| Superior mesenteric artery syndrome, gastric dilation | Abdominal pain and vomiting after meals in severe malnutrition |
- AN: low weight, fear of weight gain, body image disturbance; no "85%" or amenorrhea criterion in DSM-5-TR; severity by BMI (extreme under 15)
- AN signs: bradycardia, hypotension, hypothermia, lanugo, hypoglycemia, osteoporosis
- BN signs: enamel erosion, parotid enlargement, Russell sign, hypokalemia, metabolic alkalosis
- BED: binges with marked distress and no compensatory behavior
- First priority in AN: stabilize life-threatening medical problems
- Refeeding syndrome → hypophosphatemia, hypokalemia, hypomagnesemia; start low, go slow, thiamine first, monitor labs
- Meals: small, frequent, supervised; observe 1–2 hours after meals
- Communication: accept feelings, focus on emotions, not food or weight
- Fluoxetine for BN; lisdexamfetamine for BED; bupropion contraindicated in eating disorders
- Pica = eating nonfood substances; check iron and lead
Country Notes
United States
- Weight thresholds in teaching are usually given in pounds; BMI percentiles use CDC growth charts for youth.
- Many insurers require documented medical criteria for inpatient or residential eating disorder care; document vital signs, labs, and weight trends carefully.
Philippines
- Specialized eating disorder programs are limited; most clients are managed in general psychiatric or medical units, making nursing monitoring of electrolytes and refeeding especially important.
- Screen for pica in children and pregnant clients, where iron deficiency anemia is common.