Yes, this is often the result of an emotional trauma. I'd find out what is going on in her life including anything secretly hurting her. good luck
i have to agree with skepticalpeach..is there any..any whatsoever type of change no matter how little that has occured since this started...keep posting
Perhaps something is bothering her. Have you talked to her about it? Does she have any developmental problems? Has anything life changing happened to her recently? ie move, school change, loss of a family member/pet Please let us know more!