If your teenaged son or daughter has a friend with an eating disorder, your child may be suffering a range of difficult emotions.

Sensitive girls who like to nurture others are most likely to end up in friendships where they feel they must support their sick friends at all costs - even sacrificing their own wellbeing.

Marie Campion, director of the Marino Therapy Centre, says that the friend of the eating distress sufferer could be more in danger than the person with the condition, because the person with the eating disorder has numbed her feelings and her family are probably doing their utmost to help her.

"The friend may actually be the one feeling the most pain. If a person with an eating disorder is allowed to put her negativity on to her friend, then you have two victims."

Eating disorders start with a hypersensitive child or teenager who takes on other people's problems and feels the weight of the world upon his or her shoulders. These sensitive teens need their parents to spend a lot of time listening carefully and talking about feelings. Parents need to take their time and sensitively monitor the situation. This isn't a problem that's going to be solved overnight, Campion advises.

Spend a lot of time talking. It's best to do this not at the kitchen table, but outside the home, while going out for a coffee or taking a walk because a different environment helps the child to think about problems from a fresh perspective, Campion also suggests.

The child - not the parent - needs to decide whether to continue a friendship with a person afflicted by eating distress. Ask your child, do you really like your friend as a person? Is she a good friend to you? If the child wants to be a friend, you need to explain to your own child that the friend has a mental illness.

If your child genuinely likes the friend deep inside the eating disorder, then the child needs to tell the friend this. It can be of enormous help to the sufferer of eating distress to hear a friend say: "I really like you for who you are and I don't care how much you weigh." Teenagers listen to each other more than to their parents. For a friend to say: "I care about you, but your eating distress is really getting me down so I think we need to take a break for a while," can be a turning point for the eating distress victim.

But, most importantly, how to handle the friendship must be the child's decision.