I think it's a huge shame she's gone purely because a huge talent is no more. Put all your lady gagas and britney spears etc together and they come not even close to matching her talent.
With regards to the drug use aspect, I myself don't have much patience for it but what I will say is it's hard for any of us to have a proper grasp of what she would have been going thru and experiencing to start down that path.
Imagine in life where by you cannot seem to go any further because you have done it all, you have everything and have a guy for that a guy for this. Everything in the real world has been conquered and it may all seem down hill from there. It's out inate need to go further and "the struggle" that makes us what we are I guess and if all that has gone because you have it all or have done it, surely that's a very bizarre and scary prospect.
Until or if we experience that, we wont know ourselves but im sure it's break down material? It must be! And it probably explain why some of the great talents go down this route. There's nothing to keep their mind stimulated in the real world and that drug route will always be not too far away in the mind of someone like that. I might be talking Crap and I'm not excusing drug use but possibly a hazy insight into why creative and talented minds set off down the slippery slope of drugs?