Hi, I'd like to help you with your question.
It sounds like your daughter may either have Bipolar disorder and/or a personality disorder such as borderline or anti social.
Your daughter needs a complete evaluation from a therapist. To find a therapist, you can ask your doctor or she can ask her doctor for a referral. She can also search on line at http://www.goodtherapy.org/south-africa-counseling.htm.
If your daughter continues to have outbursts and becomes physically violent, you can contact the police or take her to the local emergency room/hospital. They may be able to do an evaluation to see if she needs admitted. Anytime someone threatens to hurt themselves or someone else, they need evaluated by a professional to determine if they are really a threat. If your daughter was admitted, she could receive treatment right away which will help her recover.
You can also try self help at home to determine how you can help your daughter. Here are some resources to help you figure out what might be going on with her:
Hidden Victims Hidden Healers: An Eight-Stage Healing Process For Families And Friends Of The Mentally Ill by Julie Tallard Johnson
Helping Someone with Mental Illness: A Compassionate Guide for Family, Friends, and Caregivers by Rosalynn Carter and Susan Golant M.A.
You can find these books on Amazon.com or your local library may have them for you.
Once you can find out what is going on with your daughter, it will be easier to focus on how to help her get better. Also, it will help your family know how to respond.
I hope this helps you,