Your child may be so immersed in the relationship, that they forget everything else. Also, when your child tries to be involved with people outside, the boyfriend or girlfriend may be very upset by this. Maybe Chris is right. College is the place to do this. However, sudden, substantial changes are cause for worry.
Depression often is a result of abusive relationships.
There is something wrong if your child typically puts a lot of time into their appearance and then suddenly stops doing so. They may fear the attention of interested people, because they know this will anger the boyfriend or girlfriend. If your child is typically very happy and easygoing and then is suddenly angry and sad, this could be a result of emotional abuse. Also, be aware of self-blame. People in abusive relationships often blame themselves for the mistreatment and feel that the emotional or physical abuse was justified.