Females are trying diets and are exercising like it is a competition to see who can lose the most weight the quickest.
Other psychological anorexia and effect include a lack of interest in doing things previously enjoyed (maybe due to general fatigue, maybe due to depression, or a combination of both).
This and low-self esteem can be partially responsible for the withdrawal from social situations and the difficulty in maintaining relationships.
They may cut or burn or otherwise harm themselves as a way of coping with painful emotions.
For people who self-mutilate, treatment with professionals experienced in dealing with that issue is paramount.
Follow this link for more detailed information on anorexia treatment.