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Anorexia nervosa (AN) is a severe psychiatric disorder characterized by self-starvation and malnutrition, a high incidence of coexisting psychiatric conditions, treatment resistance, and a substantial risk of death from medical complications and suicide. An absolute cutoff in terms of low body-mass index (BMI, which is the body weight in kilograms divided by the square of the height in meters) is not stipulated, since other factors warrant consideration, including the patient’s age, sex, and BMI before the occurrence of symptoms, and the rapidity of weight loss; however, a low body weight (i.e. BMI less than 17.5) is usually observed in adults with AN.

A central feature of AN is an intense fear of weight gain, however patients will often deny this, and it must be inferred from their behavior. An extreme focus on body weight and shape is integral to the disorder, combined with complete control over everything that is eaten, including how food is prepared.

In the U.S., the lifetime prevalence of AN is about 0.80%, and 92% of affected person are young and female, with symptoms often beginning in adolescence. It is more common in white individuals and the worldwide prevalence is increasing, especially in Asia and the Middle East. There are two designated subtypes – the restricting subtype, which is characterized by dietary restriction, and the binge-eating and purging subtype, in which restriction is accompanied by binge-eating, purging, or both. The condition may progress from one subtype to the other. The restricting subtype is associated with a lower age of onset, a better prognosis, and a greater likelihood of crossover to the other subtype. A genetic link is suspected, and cases often aggregate in families. Studies have suggested that dieting behaviors may trigger AN in susceptible persons. Psychological risk factors include perfectionism, cognitive rigidity (e.g. strict reliance on rules), and childhood anxiety disorders.

Medical complications are related to weight loss, malnutrition, and conditions linked to purging. For example, self-induced vomiting is linked to salivary gland issues and stomach and esophageal disorders up to and including esophageal and/or stomach rupture. Other medical complications include low blood pressure, dehydration, heart arrhythmias, kidney failure, loss of muscle mass, and loss of bone mass (osteoporosis) leading to bone fractures. Hospitalization is sometimes necessary, especially if the BMI is 15 or below, and involuntary hospitalization and refeeding is often required in severe cases. Long-term studies indicate that the recovery rate is 30 – 60%, with chronic illness in 20%, and residual illness in the remainder.

Treatment of AN is very difficult. In general, psychotropic medications (i.e. antidepressants) are usually ineffective. The mainstay of treatment is psychotherapy. And family interventions are often recommended in the treatment of children and adolescents. Caregivers, usually parents, typically have high levels of stress, anxiety, and depression as they often feel helpless in confronting their child’s restrictive eating and other problematic behaviors, at least early on in the course of treatment. Management of osteoporosis is a major concern, Often, vitamin D and calcium supplements are used to try to promote bone thickening.

Bisphosphonates, used in treating adults with osteoporosis, are generally not used in children and adolescents. The most difficult part of treatment is getting the patient to realize there is a problem and confront it. Sadly, all too often this goal is never achieved.

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 By Peter Galvin, MD

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