Anorexia nervosa

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 20, 2016
StartDiseasesAnorexia nervosa

Anorexia nervosa is among the most common eating disorders in the developed world. It is also among the most famous and best understood eating disorders.


Definition & Facts

Anorexia nervosa is characterized by a strong desire to remain thin combined with extreme efforts to lose weight, refusal to eat, and the mistaken perception that the patient is overweight. It is significantly more common among women than among men, and is estimated to affect between .9% and 4.3% of women in developed countries at some point in their lives, while only affecting between .2% and .3% of men in the same countries.

The majority of patients begin to suffer from the disease during early adulthood or while teenagers. The disease is strongly correlated with malnutrition and related complaints and can result in death if it goes untreated.

Symptoms & Complaints

The clearest sign that a person suffers from the disease is extreme weight loss combined with the belief that the patient is overweight. This refusal to eat as needed causes a variety of symptoms that are associated with starvation. These symptoms include hair damage and hair loss, yellowed skin, and amenorrhea which is the unhealthy cessation of the menstrual cycle. Symptoms of the heart are also common including low heart rate and low blood pressure. Many other symptoms of the disorder are psychological, and it is those psychological symptoms which most readily distinguish anorexia nervosa from other disorders that can cause malnutrition. Patients often become obsessed with the calorie content of food, and many also become very interested in cooking despite their unwillingness to eat. When patients do eat, they often do so in abnormal ways such as refusing to eat in the presence of other people or by only eating food that has been cut or arranged in certain ways. Some patients choose to eat in a relatively normal fashion but purge their meal after eating to avoid gaining weight.

Depression is common among people who suffer from this disease, and many go to great lengths to avoid other people and have trouble functioning in their daily life. Finally, many patients also suffer from rapid mood swings.


The precise cause of anorexia nervosa, like that of many other eating disorders, remains unknown. Despite the lack of precise knowledge, many factors have been discovered that are strongly correlated with the disorder and can be used to assess a person's risk of suffering from the disease. Some of the factors are biological while others are primarily social.

Anorexia nervosa is highly heritable, which indicates that a significant genetic factor is likely to contribute to the disease. Birth conditions, including a mother that suffers from anemia or diabetes mellitus, may also contribute to developing the disorder.

Given that the disorder is most common among social groups that experience strong pressure to be thin, including models and dancers, it is likely that social pressure also increases the probability of developing anorexia nervosa. The increasing frequency of the disease in recent years may be linked to increased exposure to media such as magazines and television shows that promote thinness as the ideal of beauty. That beauty ideal is more strongly associated with women than with men, which may be the reason that more women suffer from anorexia nervosa than men.

Diagnosis & Tests

A diagnosis for anorexia nervosa is based on both physical and psychological symptoms. Physical symptoms are far easier for most people to detect than the psychological symptoms, so they are usually the ones that prompt the initial medical investigation.

Patients undergo a variety of blood, urine, and enzyme analyses in order to rule out other disorders that can cause malnutrition and are thus easily confused with eating disorders. The physical tests are combined with a mental examination to determine the patient's general state of mind and their views on food. The patient's family history is also studied whenever it is available due to the highly heritable nature of the disorder.

A patient is diagnosed as suffering from anorexia nervosa if they show both the physical and mental symptoms of the disease and the testing did not reveal any information that strongly suggests a different diagnosis. The diagnosis can include a subtype of the disease, either a restrictive type that avoid eating or a binge/purge type that eats a relatively normal diet and then purges the food afterwards.

Treatment & Therapy

The first priority when treating the disorder is to help the patient reach a healthy weight. The second priority is to resolve any mental problems that contributed to the disorder in the first place. The treatment process works better the earlier that it begins.

Treatment methods vary, but all of them share some traits. They are all focused on dietary improvement, particularly increased calorie consumption. The patient's calorie consumption must increase slowly over time in order to prevent further medical problems.

Dietary changes must be combined with therapy to ensure that the patient does not revert to unhealthy behaviors after the treatment ends. Family-based treatment is usually more effective than individual treatment, especially among adolescents whose family may be inadvertently encouraging unhealthy behavior.

Cognitive behavioral therapy is used to help treat a patient's obsession with remaining thin and improve their body image. The therapy process can take a long time to complete and often needs to be tailored to the individual, but it is a vital part of treating the disorder. Pharmaceutical treatments are usually ineffective, but are occasionally useful when treating other mental disorders which have contributed to the development of anorexia nervosa.

Prevention & Prophylaxis

Anorexia nervosa is difficult to predict and thus difficult to prevent. People who are at risk of developing the disorder and who are aware of their risk factor can watch for signs that they are developing it and seek treatment quickly. Friends and family who are also aware of the risk can also watch for signs of the disorder and urge potential patients to seek treatment as quickly as possible. As with most other mental disorders, the best way to prevent problems is to be aware of the risk and to seek treatment as soon as the disorder starts to develop.