I hope you're able to get the help you need. It's really hard to have a kid who is struggling like that.
I'm chiming in to mention that there might be a medical or organic root cause, as well as the other possibilities mentioned upthread, so I wanted to add the suggestion to talk to your pediatrician or GP about ruling out conditions that could cause behavioral issues.
(In our case, it was long-undiagnosed celiac disease that contributed to increasing anxiety, irritability, tantrums/meltdowns, depressions, etc. culminating in suicidal talk and destructive behavior. Getting her on a gluten-free diet helped, as has supplementing with magnesium and vitamin D; she's still not easy but miles better, and we see the irrationality and short fuse come back when she's inadvertently exposed to trace amounts gluten via cross-contamination.)
Not saying it's necessarily celiac in your situation, but I want to make sure that you have potential organic causes on your radar, since pretty much all the professionals we consulted over years overlooked it.
