Many people with anorexia nervosa do not seek treatment, and often deny that they have a problem. However diagnosis of anorexia nervosa is essential as early treatment can improve the chance of recovery.
The first step in diagnosis of anorexia is to see a doctor. They can provide a diagnosis, physical check-up, and refer to other mental health professionals who will need to be involved.
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Firstly, the doctor will want to make sure a person's weight loss is not caused by another condition. If the doctor suspects a person has anorexia nervosa, they may make a referral to a mental health professional.
A mental health professional will assess an individual for anorexia against a list of criteria outlined in Diagnostic and Statistical Manual of Mental Disorders Version 5 (DSM-5).
To make the assessment, the mental health professional may ask the individual their thoughts, feelings and eating behaviours. They will also check for any other mental illnesses the person may have.
They may also ask the person to complete a questionnaire.
They will also do a physical exam to check an individual's weight and body mass index (BMI). A normal BMI for adults is 20 to 25. A person with anorexia will generally have a BMI below 17.5.
The doctor may also check the person's heart rate, blood pressure, temperature, heart and lungs and take some blood tests, including a blood count and specialised tests to check electrolytes, protein, liver, kidney and thyroid functioning. The doctor may also conduct a urine test.
Being underweight puts additional pressure on the body and its organs as they fight for energy. As such, the doctor may also check for any related medical complications caused by the weight loss. This could include tests for bone density, broken bones, pneumonia or heart problems.
Where to get help
If you or someone you know might have anorexia nervosa, contact the following organisations for support, information and counselling:
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Last reviewed: June 2019