They've said it wasn't an OD, at least not the kind we're used to hearing about. Her lifestyle was a factor, I assume she was on a myriad of legal drugs, and moxing those whilst being of poor health surely could have led to her death.
She was cracked anyway, and given she was depressed (understandably) so a "conventional" OD is likely I guess.
What little I know of her is that she was insane, married to a billionare corpse, and was once really quite stunning.
I can't say I particularly care that she's dead (harsh), but she wasn't in line for a happy life.