Anorexia nervosa overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Anorexia nervosa is a psychiatric eating disorder characterized by persistent restriction of energy intake leading to significantly low body weight, accompanied by an intense fear of gaining weight and disturbance in the perception of body weight or shape, with limited insight into the seriousness of the medical consequences.^[1]

Individuals with anorexia nervosa often engage in voluntary starvation, rigid dietary rules, and excessive physical activity, and may use purging behaviors, including self-induced vomiting or misuse of laxatives or diuretics, particularly in the binge-eating/purging subtype.^[1] Two subtypes are recognized: the restricting subtype and the binge-eating/purging subtype.^[1]

Anorexia nervosa occurs worldwide and affects individuals across racial, ethnic, and socioeconomic groups, though it remains more common in females than males.^[2][3][4][5] In the United States, approximately 175,000 adults are affected, with a female-to-male ratio of approximately 12:1.^[5] While onset frequently occurs during adolescence, anorexia nervosa affects both adolescents and adults, and a substantial proportion of cases remain undiagnosed or untreated.^[5]

Anorexia nervosa is a multisystem disease associated with significant medical morbidity. Common complications include bradycardia, hypotension, QT interval prolongation, electrolyte disturbances, endocrine suppression, and reduced bone mineral density, which may lead to osteoporosis and increased fracture risk.^[6][7] Endocrine adaptations include hypothalamic amenorrhea and alterations in thyroid function consistent with the sick euthyroid syndrome.^[7]

Psychiatric comorbidity is common. In a nationally representative US sample, the lifetime prevalence of major depressive disorder among individuals with anorexia nervosa was 49.5%, and the lifetime prevalence of anxiety disorders was 40.5% (Udo & Grilo, 2019). Suicide attempts have been reported in approximately 24.9% of individuals with anorexia nervosa.^[5]

Anorexia nervosa has one of the highest mortality rates of any psychiatric disorder. A meta-analysis of 36 studies reported a mortality rate of 5.1 deaths per 1000 person-years, corresponding to a standardized mortality ratio of 5.86, with approximately 25% of deaths attributable to suicide.^[8] Although weight restoration can be achieved in many patients, relapse rates of 40–50% within one year after intensive treatment have been reported.^[9][10]

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