I would consult with a homeopathic vet IMMEDIATELY. They will be able to counsel you on dietary changes, behavioral modification and through homeopathic remedies, these doctors are able to cure problems that regular vets just CAN'T.
My Cavalier King Charles Spaniel had chronic AWFUL colitis and vaccinosis from his rabies vaccine that caused prey behavior and extreme aggression issues. I did a quick look in my homeopathy manual and there are remedies for rage syndromes and mental disorders.
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AHVMA - Home and naturalholistic.com for a refferal. I was not a believer in homeopathy and now that is how I treat my dogs and myself. I have had chronic health issues my whole life cured by homeopathy and on a side note - this is how the Queen of England gets cared for. Good luck and be prepared to search outside traditional veterinary care - I believe there is hope for your little one and she can find peace and happiness.
Please let us know how its going.