We actually know very little about her mental health -from mental health experts- but we have some pretty good descriptions from those who saw her during her last fortnight. There are supporters who would like everyone to believe she was working up to another psychotic episode -if she was it was clearly different from symptoms she'd previously exhibited- I'm inclined to believe she was deeply depressed.
I agree she appeared withdrawn and depressed ...
My personal opinion is that depression is anger turned in on one self ...
Maybe she was supressing a growing amount of anger ?
In my opinion anger often comes from fear ...
Maybe her delusional thinking was ramping up her fear levels too much for her to cope ...
And that caused a full blown psychotic attack ?