25 yr old stepdaughter as a teenager threatened to kill her sister when she fell asleep, killed a kitten with her bare hands, and tried to slit her wrists, always been aggressive. Is verbally abusive, throws tantrums. Leaves nasty messages, sends nasty letters when family or friends don't do what she expects them to or react the way she wants. She has a 3 year old and I'm tempted to hot line her. She lives with her mother and there is always pot in the house. Is she bipolar, just unstable or is the drugs and booze that she's used since 15 yrs old?