Is this a behavior disorder?

Background:  My daughter is 9 years old.  Diagnosed with Petit Mal seizures at age 7.  On Lamictal, 100 mg in morning, 75 mg in evening, for seizures.  Also diagnosed with a mild form of tourettes syndrome.  Not medicated for tourettes.  She has social issues with peers and adults (has to be told to say hello and answer when spoken to, etc.) but is improving in this area.  

When she was in PreK and Kindergarten she was, what I would call obsessed, with one child who was in her class and also lives across the street from us.  She just wanted to play with this child and no other children.  She would not want (would try to physically block them) other children to play with this child.  Always had to sit next to this child in class, etc.  It caused problems to the point that the parents of the child will not allow them to play together.  I have requested since 1st grade that they not be put in the same class together.

After the other child was taken out of the picture we feared that she would just replace the child with another child.  This did not happen and in fact the situation improved dramatically.  Our daughter started to make multiple friends and started doing much better socially with her peers.  The improvement went on from grade 1 until recently (the past 3 weeks) (she is now in 3rd grade).  What seems to us to be out of the clear blue she has picked one of her friends (lives very close to us and has been in her class for the last 3 years) to become obsessed with.  It is like preK and Kindergarten all over again.  This behavior is noticed by us (her parents), her teacher and the other child

[Kevin Kennedy, Ph.D.]

At this age children tend to become very focused on 'who likes whom' and can sometimes have difficulty tolerating so-called triangles. That is, they can handle friendships with one other person, and when a third enters the mix some children get unsettled. They view the presence of the third person as a threat to their friendship with the other person. Over time, children see that they can be friends with more than one person and friendships can be shared. It's important that you don't attempt to program your daughter's friendships, but at the same time it will be useful to arrange times for her to be with children other than her favored friend. This is a developmental process and, over time, tends to work out OK.

[DinaGrimes]

We feel that her behavior is a little out of the norm.  Can you give us a little more feedback on how to handle this situation before she ends up alienating herself.

[Kevin Kennedy, Ph.D.]

In practical terms, it's best for now that she play (outside of school) with a single peer at a time. But it does not have to be the peer she prefers. Children so young are not famous for their introspective abilities, so a little bit of talk and then planning around play situations is what's called for. If her school or a local agency has a social skills group, she could benefit from such intervention. I agree with your point that yur daughter's behavior is not within the norm, but the issue she's facing is a normal developmental challenge. The difficulty with handling 'triangles' does tend to be more acute with girls than it does with boys.