Anorexia nervosa is restriction of energy intake leading to significantly low body weight, with intense fear of weight gain and disturbance in body image perception. The DSM-5 removed the amenorrhea criterion and broadened the weight criterion, but the core features remain: restriction below expected weight, fear of weight gain disproportionate to current weight, body image disturbance.
Two subtypes:
Restricting subtype — weight loss through dieting, fasting, or excessive exercise without regular binge or purge behaviors.
Binge-eating/purging subtype — episodes of binge eating and/or purging behaviors during the current episode.
Mortality is among the highest in psychiatry. Standardized mortality ratio approximately 5-10x age-matched controls. Causes of death: medical complications (cardiac arrhythmias from electrolyte abnormalities, refeeding syndrome, organ failure in severe malnutrition), suicide (substantially elevated risk). Long-term mortality across follow-up studies typically 5-10% — sobering numbers for a "psychiatric" disorder.
Medical complications: bradycardia and hypotension (often signs of starvation-induced cardiovascular suppression), arrhythmias from electrolyte imbalances (particularly hypokalemia from purging), amenorrhea and infertility, osteoporosis (often irreversible bone loss in young patients), gastrointestinal complications (gastroparesis, constipation), dermatologic changes (lanugo hair, dry skin), cognitive effects from malnutrition.
Refeeding syndrome — life-threatening electrolyte shifts (hypophosphatemia particularly, also hypokalemia, hypomagnesemia, thiamine deficiency) that occur when nutritional intake is reintroduced after starvation. Can produce cardiac arrhythmias, heart failure, neurologic complications. Critical concept for inpatient refeeding: start low, go slow, monitor electrolytes daily, supplement thiamine before any glucose.
Treatment by age and severity:
Adolescents: family-based therapy (FBT, Maudsley method) has the strongest evidence. Parents take temporary control of refeeding while therapy addresses family dynamics. Three phases over 6-12 months. Remission rates substantially higher than other approaches in adolescent populations.
Adults: CBT-Enhanced (CBT-E), specialist supportive clinical management (SSCM), MANTRA (Maudsley Anorexia Nervosa Treatment for Adults). Less dramatic results than FBT in adolescents but meaningful improvement in many patients.
Medical stabilization first when severely underweight or medically unstable. Inpatient refeeding for severe cases, often via specialized eating disorder units.
Pharmacotherapy is adjunctive, not curative. Olanzapine has modest evidence for weight gain in severely underweight patients. SSRIs generally ineffective during severe malnutrition (the malnourished brain doesn't respond well); may help comorbid depression/anxiety after weight restoration.
Coordinated care: psychiatrist or eating disorder specialist, nutritionist, primary care physician, sometimes gastroenterology, cardiology, endocrinology depending on complications. Multidisciplinary teams produce better outcomes than fragmented care.
Course and prognosis: roughly 50% achieve full recovery, 30% partial recovery, 20% chronic course or death. Earlier intervention and shorter duration of illness predict better outcomes. Recovery is possible — many patients regain full health, normal weight, normal relationship to food.
When you encounter a patient with anorexia nervosa, recognize the medical stakes. Refer to specialized care if available. Coordinate with primary care for medical monitoring. The combined psychological and medical approach saves lives.