Anorexia nervosa occurs predominantly in girls and young women. Onset is usually during adolescence and rarely after age 40 (1). Lifetime prevalence is approximately 1.5% in women and 0.1% in men (2).
Two types of anorexia nervosa are recognized:
Restricting type: Patients restrict food intake but do not regularly engage in binge eating or purging behavior; some patients exercise excessively.
Binge eating/purging type: Patients regularly binge eat and/or induce vomiting and/or misuse laxatives, diuretics, or enemas. This is distinguished from bulimia nervosa by the patient's weight: in anorexia weight is low; in bulimia weight is normal or high.
Binges are defined as consumption of a much larger amount of food than most people would eat in a similar time period under similar circumstances with loss of control, ie, perceived inability to resist or stop eating.
References
1. Uniacke B, Walsh BT. Eating Disorders. Ann Intern Med. 2022 Aug;175(8):ITC113-ITC128
2. Udo T, Grilo CM. Prevalence and Correlates of DSM-5-Defined Eating Disorders in a Nationally Representative Sample of U.S. Adults. Biol Psychiatry. 2018;84(5):345-354. doi:10.1016/j.biopsych.2018.03.014
Risk Factors for Anorexia Nervosa
Incidence is higher in females (1, 2). Certain familial and social factors are associated with higher risk. Many, though not all (3, 4), patients with anorexia nervosa are in middle or upper socioeconomic classes, are meticulous and compulsive, and have very high standards for achievement and success.
Cultural norms about body image may play a role. In some cultures, obesity is considered unattractive and the desire to be thin is pervasive, even among children; this may predispose to the development of anorexia nervosa. For example, in the United States, up to 40% of preadolescent and early adolescent girls diet or take other measures to control their weight; however, only a small proportion of girls develop anorexia nervosa (5, 6).
In addition, participation in activities emphasizing body shape or weight (eg, gymnastics, ballet) have been associated with the development of anorexia nervosa and bulimia nervosa (7).
A genetic predisposition has been identified for anorexia nervosa and genome-wide studies have begun to identify specific loci that are associated with increased risk (8).
Risk factors references
1. Mitchell JE, Peterson CB. Anorexia Nervosa. N Engl J Med. 2020;382(14):1343-1351. doi:10.1056/NEJMcp1803175
2. van Eeden AE, van Hoeken D, Hoek HW. Incidence, prevalence and mortality of anorexia nervosa and bulimia nervosa. Curr Opin Psychiatry. 2021;34(6):515-524. doi:10.1097/YCO.0000000000000739
3. Koch SV, Larsen JT, Plessen KJ, Thornton LM, Bulik CM, Petersen LV. Associations between parental socioeconomic-, family-, and sibling status and risk of eating disorders in offspring in a Danish national female cohort. Int J Eat Disord. 2022;55(8):1130-1142. doi:10.1002/eat.23771
4. Huryk KM, Drury CR, Loeb KL. Diseases of affluence? A systematic review of the literature on socioeconomic diversity in eating disorders. Eat Behav. 2021;43:101548. doi:10.1016/j.eatbeh.2021.101548
5. Rodgers RF, Peterson KE, Hunt AT, et al. Racial/ethnic and weight status disparities in dieting and disordered weight control behaviors among early adolescents. Eat Behav. 2017;26:104-107. doi:10.1016/j.eatbeh.2017.02.005
6. Schreiber GB, Robins M, Striegel-Moore R, Obarzanek E, Morrison JA, Wright DJ. Weight modification efforts reported by black and white preadolescent girls: National Heart, Lung, and Blood Institute Growth and Health Study. Pediatrics. 1996;98(1):63-70.
7. Attia E, Walsh BT. Eating Disorders: A Review. JAMA. 2025;333(14):1242-1252. doi:10.1001/jama.2025.0132
8. Xu J, Igudesman D, Huckins L, Bulik CM. Genetics of Anorexia Nervosa: Translation to Future Personalized Therapies. Psychiatr Clin North Am. 2025 Jun;48(2):293-309.
Symptoms and Signs of Anorexia Nervosa
Anorexia nervosa may be mild and transient or severe and persistent.
Even though they are underweight, most patients are concerned that they weigh too much or that specific body areas (eg, thighs, buttocks) are too fat. They persist in efforts to lose weight despite reassurances and warnings from friends and family members that they are thin or even significantly underweight, and they view any weight gain as an unacceptable failure of self-control. Preoccupation with and anxiety about weight increase even as emaciation develops.
Anorexia is a misnomer because appetite often remains until patients become significantly cachectic. Patients are preoccupied with food:
They may study diets and calories.
They may hoard, conceal, and waste food.
They may collect recipes.
They may prepare elaborate meals for other people.
Patients often exaggerate their food intake and conceal behavior, such as induced vomiting. Binge eating/purging occurs in approximately 45% of patients (1). Others simply restrict their food intake.
Many patients with anorexia nervosa also exercise excessively to control weight. Even patients who are cachectic tend to remain very active (including pursuing vigorous exercise programs).
Reports of bloating, abdominal distress, and constipation are common. Most women with anorexia nervosa develop irregular menses and eventually amenorrhea. Depression and anxiety occur frequently.
Common physical findings include bradycardia, hypotension (particularly orthostatic), hypothermia, lanugo hair (soft, fine hair usually found only on neonates) or slight hirsutism, and edema. Body fat is greatly reduced, as is muscle mass. Patients who vomit frequently may have eroded dental enamel, painless salivary gland enlargement, and/or an inflamed esophagus.
Symptoms and signs reference
1. Mitchell JE, Peterson CB. Anorexia Nervosa. N Engl J Med. 2020;382(14):1343-1351. doi:10.1056/NEJMcp1803175
Complications of Anorexia Nervosa
Endocrine abnormalities are common in anorexia nervosa; they include
Decreased levels of gonadal hormones
Mildly decreased levels of thyroxine (T4) and triiodothyronine (T3)
Increased cortisol secretion
In severely undernourished patients, virtually every major organ system may be affected. However, patients do not become immunosuppressed, and susceptibility to infections is typically not increased.
Dehydration and metabolic alkalosis may occur, and hypokalemia and hyponatremia may be present; all are aggravated by induced vomiting and laxative or diuretic use. Anemia and thrombocytopenia may be seen due to bone marrow suppression. Osteoporosis may develop.
Bradycardia is common. Cardiac muscle mass, chamber size, and output decrease; mitral valve prolapse is commonly detected. Some patients have prolonged QT intervals related to electrolyte disturbances (particularly hypokalemia), which may predispose to tachyarrhythmias. Sudden death, most likely due to ventricular tachyarrhythmias, may occur.
Diagnosis of Anorexia Nervosa
Psychiatric assessment
Laboratory testing and electrocardiography
Patients do not recognize the health risks of the weight loss, low body weight, and restrictive eating; they are usually brought to the physician’s attention by family members or by intercurrent illness. Patients usually resist evaluation and treatment.
Clinical criteria for diagnosis of anorexia nervosa from the Diagnostic and Statistical Manual of Mental Disorders, 5th ed, Text Revision (DSM-5-TR) include the following (1) :
Restriction of food intake resulting in a significantly low body weight
Fear of excessive weight gain or obesity (stated specifically by the patient or manifested as behavior that interferes with weight gain)
Body image disturbance (misperception of body weight and/or appearance) or denial of the seriousness of illness
In adults, low body weight is defined using the body mass index (BMI). BMI of < 17 kg/m2 is considered significantly low; BMI 17 to < 18.5 kg/m2 may be significantly low depending on the patient's starting point.
For children and adolescents, the BMI percentile for age is used; the fifth percentile is usually given as the cutoff. However, children above the fifth percentile who have not maintained their projected growth trajectory may also be considered to meet the criterion for low body weight; BMI percentile for age tables and standard growth charts are available from the Centers for Disease Control and Prevention (see CDC Growth Charts). Separate BMI calculators are available for children and adolescents.
Patients may otherwise appear well and have few, if any, abnormalities in blood tests. The key to diagnosis is identifying persistent active efforts to avoid weight gain and an intense fear of fatness that is not diminished by weight loss. Laboratory testing and electrocardiography may be useful to identify electrolyte abnormalities, anemia and thrombocytopenia, screen for arrhythmia, and evaluate nutritional status. Testing may also help determine if hospitalization is indicated (2).
Differential diagnosis
Another psychiatric disorder, such as schizophrenia or primary depression, may cause weight loss and reluctance to eat, but patients with these disorders do not have a distorted body image.
Rarely, an unrecognized severe general medical disorder may cause substantial weight loss. Disorders to consider include malabsorption syndromes (eg, due to inflammatory bowel disease or celiac disease), new-onset type 1 diabetes, adrenal insufficiency, and cancer. Amphetamine misuse may cause similar symptoms.
Diagnosis references
1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed, Text Revision. American Psychiatric Association Publishing; 2022:pp 381-387.
2. Crone C, Fochtmann LJ, Attia E, et al. The American Psychiatric Association Practice Guideline for the Treatment of Patients With Eating Disorders. Am J Psychiatry. 2023;180(2):167-171. doi:10.1176/appi.ajp.23180001
Treatment of Anorexia Nervosa
Nutrition supplementation
Psychotherapy (eg, cognitive behavioral therapy)
For children and adolescents, family-based treatment
Sometimes second-generation antipsychotics
Treatment of anorexia nervosa may require life-saving short-term intervention to restore body weight and correct electrolyte abnormalities, particularly in the setting of symptomatic hypotension, extreme bradycardia, or other arrhythmia. When weight loss has been severe or rapid or when weight has fallen below approximately 75% of recommended weight, prompt restoration of weight becomes critical, and hospitalization should be considered (1). If any doubt exists, patients should be hospitalized.
Outpatient treatments may include varying degrees of support and supervision and commonly involve a team of practitioners.
Nutritional supplementation is often used with behavioral therapy that has clear weight-restoration goals. Nutritional supplementation begins by providing about 30 to 40 kcal/kg/day and is gradually increased; this regimen can produce weight gains of up to 1.5 kg/week during inpatient care and 0.5 kg/week during outpatient care (2–4). Oral feedings using solid foods are best; many weight restoration plans also use liquid supplements. Very resistant, undernourished patients occasionally require nasogastric tube feedings.
Refeeding syndrome, a potentially serious metabolic derangement characterized by hypophosphatemia and other electrolyte abnormalities, occurs rarely and particularly among the most undernourished patients (5).
Elemental calcium and vitamin D are commonly prescribed for decreased bone density. The role of estrogen and bisphosphonates are unclear (Elemental calcium and vitamin D are commonly prescribed for decreased bone density. The role of estrogen and bisphosphonates are unclear (6).
Once nutritional, fluid, and electrolyte status has been stabilized, long-term treatment begins. Outpatient psychotherapy is the cornerstone of treatment. Treatments should emphasize behavioral outcomes such as normalized eating and weight. Treatment should continue for a full year after weight is restored. Results are best in adolescents who have had the disorder < 6 months.
Family therapy, particularly using the Maudsley model (also called family-based treatment), is useful for adolescents (3, 6, 7). This model has 3 phases:
Family members are taught how to refeed the adolescent (eg, through a supervised family meal) and thus restore the adolescent’s weight (in contrast to earlier approaches, this model does not assign blame for the development of the disorder to the family or the adolescent).
Control over eating is gradually returned to the adolescent.
After the adolescent is able to maintain the restored weight, therapy focuses on engendering a healthy adolescent identity.
Treatment of anorexia nervosa is complicated by patients' abhorrence of weight gain and denial of illness. The physician should attempt to provide a calm, concerned, stable relationship while firmly encouraging a reasonable caloric intake.
Treatment also involves regular follow-up monitoring and often a team of health care practitioners, including a nutritionist, who may provide specific meal plans or information about the calories needed to restore weight to a normal level.
Although psychotherapy is the primary treatment, medications are sometimes helpful. Olanzapine may aid weight gain (Although psychotherapy is the primary treatment, medications are sometimes helpful. Olanzapine may aid weight gain (3).
Treatment references
1. Khalifa I, Goldman RD. Anorexia nervosa requiring admission in adolescents. Can Fam Physician. 2019;65(2):107-108.
2. Grilo CM. Treatment of Eating Disorders: Current Status, Challenges, and Future Directions. Annu Rev Clin Psychol. 2024;20(1):97-123. doi:10.1146/annurev-clinpsy-080822-043256
3. Attia E, Haiman C, Walsh BT, Flater SR. Does fluoxetine augment the inpatient treatment of anorexia nervosa?. . Does fluoxetine augment the inpatient treatment of anorexia nervosa?.Am J Psychiatry. 1998;155(4):548-551. doi:10.1176/ajp.155.4.548
4. Bargiacchi A, Clarke J, Paulsen A, Leger J. Refeeding in anorexia nervosa. Eur J Pediatr. 2019;178(3):413-422. doi:10.1007/s00431-018-3295-7
5. Redgrave GW, Coughlin JW, Schreyer CC, et al. Refeeding and weight restoration outcomes in anorexia nervosa: Challenging current guidelines. Int J Eat Disord. 2015;48(7):866-873. doi:10.1002/eat.22390
6. Mitchell JE, Peterson CB. Anorexia Nervosa. N Engl J Med. 2020;382(14):1343-1351. doi:10.1056/NEJMcp1803175
7. Accurso EC, Fitzsimmons-Craft EE, Ciao AC, Le Grange D. From efficacy to effectiveness: comparing outcomes for youth with anorexia nervosa treated in research trials versus clinical care. Behav Res Ther. 2015;65:36-41. doi:10.1016/j.brat.2014.12.009
Prognosis for Anorexia Nervosa
Mortality rates are relatively high in anorexia nervosa, although unrecognized mild disease likely rarely leads to death (1–3). A meta-analysis that included 35 studies and over 12,000 participants with anorexia nervosa reported a mortality rate of 5.1 deaths per 1000 person-years (among these deaths, 1.3 per 1000 person-years were due to suicide) (4).
With treatment, prognosis is as follows:
Half of patients regain most or all of lost weight, and any endocrine and other complications are reversed.
About one-fourth have intermediate outcomes and may relapse.
The remaining one-fourth have a poor outcome, including relapses and persistent physical and mental complications
Children and adolescents treated for anorexia nervosa appear to have a similar risk of relapse when compared with adults (1).
Prognosis references
1. de Rijk ESJ, Almirabi D, Robinson L, Schmidt U, van Furth EF, Slof-Op 't Landt MCT. An overview and investigation of relapse predictors in anorexia nervosa: A systematic review and meta-analysis. Int J Eat Disord. 2024;57(1):3-26. doi:10.1002/eat.24059
2. Arcelus J, Mitchell AJ, Wales J, Nielsen S. Mortality rates in patients with anorexia nervosa and other eating disorders. A meta-analysis of 36 studies. Arch Gen Psychiatry. 2011;68(7):724-731. doi:10.1001/archgenpsychiatry.2011.74
3. Mitchell JE, Peterson CB. Anorexia Nervosa. N Engl J Med. 2020;382(14):1343-1351. doi:10.1056/NEJMcp1803175
4. Solmi M, Monaco F, Højlund M, et al. Outcomes in people with eating disorders: a transdiagnostic and disorder-specific systematic review, meta-analysis and multivariable meta-regression analysis. World Psychiatry. 2024;23(1):124-138. doi:10.1002/wps.21182
Key Points
Patients with anorexia nervosa have an intense fear of gaining weight or becoming fat that persists despite all evidence to the contrary.
In the restricting type of anorexia nervosa, patients restrict food intake and sometimes exercise excessively but do not regularly engage in binge eating or purging.
In the binge eating/purging type, patients regularly binge eat and/or induce vomiting and/or misuse laxatives, diuretics, or enemas in an attempt to purge themselves of food.
In adults, BMI is significantly low (usually BMI of < 17 kg/m2), and in adolescents, BMI percentile is low (usually < fifth percentile) or does not increase as expected for normal growth.
Endocrine or electrolyte abnormalities or cardiac arrhythmias may develop, and death can occur.
Treat with nutritional supplementation, psychotherapy (eg, cognitive behavioral therapy), and, for adolescents, family-based therapy; olanzapine may be helpful.Treat with nutritional supplementation, psychotherapy (eg, cognitive behavioral therapy), and, for adolescents, family-based therapy; olanzapine may be helpful.
Drugs Mentioned In This Article
