You are right to be concerned. It sounds like your daughter has been increasingly isolating herself. Although successful in that she goes to school, her friendship circle is very limited for someone her age. Although it’s not unusual for people to talk through problems or to review their day with themselves in the privacy of the bathroom or their own room, your report that she may be punishing herself by screaming and slapping isn’t typical or okay.
Sometimes our kids can’t tell us what is troubling them so they consciously or unconsciously leave hints around so that we’ll find them. Kids sometimes “accidentally” leave a diary open where we’ll find it or “accidentally” leave a distressing email open on the family computer, for example. It’s their way of sending out a distress signal without having to quite take responsibility for doing so.
I’m guessing your daughter’s lengthy time in the bathroom is something like that. On some level she knows that you will be concerned about a two-hour stay in there.
It’s past time for you to respond to the signal. Find a therapist who specializes in young adults. Ask your doctor for a referral or click on the “Find Help” tab on the PsychCentral homepage. There may also be a behavioral health clinic at her college. Brief the therapist on the phone and ask for some guidance about how to get your daughter to go in. (Sometimes it’s helpful if a parent goes to part of the first session.)
Then, in a loving way, let your daughter know how concerned you are. Tell her that you know that she is upset and that you want to help. Reassure her that she doesn’t deserve to be punished by herself or by anyone else – no matter what. Insist that she see the counselor. Tell her you are willing to go with her. Don’t argue. Don’t get mad. Stay in that loving, concerned place.
Parenting doesn’t end because a child is at the age to start leaving home. We all have to figure out when to let go and when to still pull the “parent card.” In this situation, your daughter is telling you without words that she needs you to be a mom. Please follow through. She sounds like she really needs help.
I wish you well.