Eating disorders
Eating disorders are psychiatric conditions marked by severely disturbed eating behaviors and distorted attitudes toward food, weight, and body shape. The major diagnoses are anorexia nervosa, bulimia nervosa, and binge-eating disorder.
Eating disorders are serious mental health conditions in which disturbed eating behavior and preoccupation with weight or body image significantly harm physical health and daily functioning. The three principal diagnoses are anorexia nervosa, bulimia nervosa, and binge-eating disorder, with onset most common in adolescence and young adulthood.
Anorexia nervosa involves restriction of intake leading to significantly low body weight, intense fear of gaining weight, and distorted body image. Medical consequences are extensive: bradycardia, hypotension, amenorrhea, osteoporosis, lanugo (fine body hair), and electrolyte disturbances — it carries one of the highest mortality rates of any psychiatric illness. Bulimia nervosa pairs recurrent binge eating with compensatory behaviors such as self-induced vomiting or laxative misuse in a person of typically normal weight; purging causes hypokalemia, metabolic alkalosis, dental enamel erosion, parotid swelling, and knuckle calluses (Russell's sign). Binge-eating disorder features recurrent binges with loss of control but no compensatory behavior.
Recognition matters well beyond psychiatry. In athletes, disordered eating combines with menstrual dysfunction and low bone density in the female athlete triad, and relative energy deficiency impairs performance and recovery. Refeeding a severely malnourished patient too quickly can trigger dangerous electrolyte shifts (refeeding syndrome), so treatment is multidisciplinary: nutritional rehabilitation, psychotherapy, and medical monitoring.
Eating disorders appear across several exams. USMLE Step 1 tests the diagnostic criteria and physical findings in behavioral science, the NCLEX covers nursing care of patients with eating disorders, and the CSCS tests recognition and referral in athletes within its sport nutrition content.
Key takeaways
- The major eating disorders are anorexia nervosa, bulimia nervosa, and binge-eating disorder.
- Anorexia involves low body weight with distorted body image and has one of the highest mortality rates in psychiatry.
- Bulimia pairs binges with purging at normal weight, producing hypokalemia, enamel erosion, and Russell's sign.
- In athletes, disordered eating contributes to the female athlete triad and impaired performance.
- USMLE Step 1, NCLEX, and CSCS all test recognition, physical findings, and appropriate management or referral.