Anorexia nervosa is a complicated disorder to diagnose.  Individuals with anorexia often attempt to hide the disorder.  Denial and secrecy frequently accompany other symptoms.  It is unusual for an individual with anorexia to seek professional help because the individual typically does not accept that she or he has a problem (denial).  In many cases, the actual diagnosis is not made until there are other medical complications.  The individual is often brought to the attention of a professional by family members only after  a marked weight loss has occurred.  When anorexia finally comes to the attention of the health professional, they often lack insight into their problem despite being severely malnourished and may be unreliable in terms of providing accurate information.  Therefore, it is often necessary to obtain information from parents or other family members in order to evaluate the degree of weight loss and extent of the disorder.

The actual criteria for anorexia nervosa are found in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).