Anorexia criteria

Thanks for your post. I'll try my best to answer your question.

Here is what a psychologist or mental health professional uses to diagnose anorexia:

A. Refusal to maintain body weight at or above a minimally normal weight for age and height (e.g., weight loss leading to maintenance of body weight less than 85% of that expected; or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected).

B. Intense fear of gaining weight or becoming fat, even though underweight.

C. Disturbance in the way in which one's body weight or shape is experienced, undue influence of body shape on self-evaluation, or denial of the seriousness of the current low body weight.

D. In postmenarcheal females, amenorrhea, i.e., the absence of at least three consecutive menstrual cycles.

Type: Restricting Type vs. Binge-Eating/Purging Type.

This is taken directly from DSM-IV. American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders (4th ed.). Washington, DC.

So to answer your question, there are a few components to an eating disorder. There are physical and emtional factors that impact disordered eating. It's difficult to say if it's the brain that is malfunctioning or someone's need to control their emotions. While these are both certainly relevant, they cannot fully explain why someone may or may not have an eating disorder. I hope this helps. Good luck to you and your family member.