Everyone is responsible for their behavior and choices and she had hers. She didn't drink or take drugs cause someone forced her to do that, that's clear. She wanted to sing and as she said she didn't ask to be famous. But when you are famous, when people like you and when you make lots of money from it, you kind of get hooked to it.
I remember thinking many times about her situation and feeling sorry for her. Sorry because she was a victim. Victim of the music industry, of the age of consumerism, where music can't be enjoyed simply for what it is but must be connected to money, profit, contracts, touring...How can you not feel sorry when she comes out on the stage and can hardly stand on her feet but the band is playing, she must sing, "the show must go on", as Freddie Mercury sang. Why nobody in the band and the people around her said "we are not going to continue to do this until you fix yourself?"
People would go to someones concerts to get what they want (enjoyment, high) and would not give a damn for the musician as a person. That's what we are like. And that's sad also.