She he hard stuff like many, got hooked, had no support to get off it. I don't really have much sympathy for people that OD.
Which just shows how much we actually understand about stress.
There is no evidence she overdosed or was taking illegal drugs. There are articles that state that she managed to get herself off illegal drugs. The drugs she had were prescription ones and probably legally given by a doctor. Until the toxicology report there is no evidence available that she overdosed on those.
There has been a rumour put out that she didn't have enough water in her lungs to drown, that is plain nonsense. When water gets inside someone's windpipe there is an automatic closing action. That can choke people on as little as a mouthful of water. Plenty of drown people have no water in their lungs at all.
So it is quite possible that she went to have a bath, fell asleep and then drown. The question is, did she have the drugs in her system and how much?
As to being able to sink under the radar, I doubt if she could, she's far too well known. Effectively she would have to imprison herself. That doesn't seem to be the problem here anyway, I would guestimate that it was as much a problem of self esteem, which affects far too many people, and stage anxiety.