Q. My 30-year-old daughter is almost completely alienated from the family and we don't know why. She contacts my husband and me maybe twice a year and doesn't have anything to do with her two younger sisters.

I try to keep the door open by writing her notes, leaving messages, inviting her to family gatherings, etc., but it is usually a futile endeavor. Instead she has "adopted" another family and treats us as distant acquaintances.

This daughter always had social anxiety, anger issues and many problems in school, but we tried to deal with them through counseling and other interventions. Nothing, however, seemed to help her and nothing is helping us now.

There are so many books that deal with parents who have lost children through death, but I can't find anything to help us deal with loss through alienation. The books I have found take the position that the parents must have abused their children in some way to cause such a rift in their relationship, but that was not the case with us. We were caring, loving parents who tried to help her with her problems, we are an intact family and we have good relationships with our other two daughters.

How can we deal with our sadness and our deep sense of loss?

A. One hundred years from now our great-great-great-grandchildren will probably look back at us and say, "The poor things. They didn't understand children at all, did they?" And they'll be right.

Although scientists have put children through thousands of studies, therapies and high-tech tests, they still can't tell us why they do some of the things that they do, such as walking away from their families for no reason at all.

Some grown children do drop one or both parents if they get a divorce. Some shut out a parent who has abused them, physically or emotionally, or become an alcoholic or a drug addict. A few snub their parents if their spouses can't bear to share them with anyone else. But very few walk away from their parents and never say why. This seems to have been the case with your daughter, however.

The split may have occurred because her temperament is so different from any other temperament in the family; because her blood chemistry got out of whack or because she is deeply sensitive. Your daughter is like the princess who gets a backache if someone puts a pea under her mattress: she gets offended if someone makes a slightly negative comment even though the remark is too small to be noticed by anyone else.

Or maybe your daughter has been angry ever since you and her dad had the audacity to bring another daughter home from the hospital and she got even madder when you did it again. In the back of her mind this firstborn thinks, "Wasn't I good enough?"

It will do no good to apologize to your daughter for giving her two sisters - or for anything else - but you could start sending the same notes, messages and invitations to all of your daughters, instead of just sending them to her. When you single her out, she may think that you're tugging your forelock and begging for verbal crumbs, and that won't do.

However, you and your husband might ask your daughter to go to a therapist with you - with or without her sisters - so you can find out if there are any changes you might make, so she would want to visit you more often. And if she won't go with you? Go without her. The therapist will give you new ways to cope and may even identify her problem.

You may find out that she simply never bonded with you the way you bonded with her. If that's the case, read "Becoming Attached" by Robert Karen (Oxford, $22) and if this book strikes a chord, read "Treating Attachment Disorders" by Karl Heinz Brisch (Guilford, $30), so you'll know how to deal with them.

If the therapist says that your daughter can only empathize with herself however, you might read some books about narcissism, such as "Disarming the Narcissist" by Wendy T. Behary (New Harbinger, $17), and "Emotional Blackmail" by Susan Forward and Donna Frazier (Harper, $14) so you can resist it.

If none of this works, then accept this daughter as she is, not as you want her to be, and accept yourself, too. You and your husband have been good parents, even if she doesn't know it.

Questions? Send them to advice@margueritekelly.com.