A mental health professional, such as a psychiatrist, psychologist or social worker, can diagnose anorexia nervosa based on your history reported by the patient and the family. The person with anorexia nervosa may not report symptoms reliably, so reports from family members may be necessary to make a diagnosis. A pediatrician or primary care physician may make the diagnosis, too.
The health care professional will ask about the person's attitudes toward weight, food and body image, and will check for lower than normal body weight and the physical signs of starvation, which include:
Low blood pressure
Enlarged salivary glands
Lanugo, a very fine type of body hair
The stopping of periods in a woman
Dental problems because stomach acids can damage teeth if the person purges regularly)
The health care professional may use screening tests, such as the Eating Disorders Inventory and the Eating Attitudes Test.
The health care professional may explore whether the person has other problems that need treatment, such as depression, anxiety, obsessive-compulsive disorder, personality disorders or substance abuse. It is common for people with anorexia nervosa to have symptoms of depression, including low mood, social withdrawal, irritability, poor sleep and diminished interest in sex. People with the bingeing/purging type of anorexia nervosa are more likely to have mood ups and downs, have problems with impulse control, and abuse alcohol or drugs.
Medical evaluation includes blood work to investigate whether poor nutritional intake has caused anemia (low red blood cell count), altered liver and kidney function and abnormal levels of blood chemicals, such as low potassium.
A doctor also needs to make sure there are no other medical problems that might be causing weight loss, such as inflammatory bowel disease, cancer or hormonal problems. People with those illnesses do not usually have a problem with their body image.
How long anorexia nervosa lasts varies. Some people have a single, relatively brief episode after experiencing an isolated stressful event. For others, the problem becomes chronic (long-lasting) and the person's condition gradually deteriorates. Many people start by restricting food, then later binge and purge. Although the majority of cases go away by late adolescence, a significant number of people have continuing problems with diet and body image into adulthood.