She is not even 27, like Robert Johnson, Hendrix, Joplin, Morrison, Cobain, Winehouse and others in the "27 Club".
In the case of Joplin and I suspect others, it was accidental overdose.
And of course very stupid. But not intentional suicide.
A drug user comes to rely on the strength, of drugs from a dealer. If the strength goes way up because it was not cut as much upstream, overdose could occur. Another factor could be deteriorating overall health (Michael Jackson, Amy Winehouse).
Artistic types (disproportionately left handed, too) are prone to depression, etc. They self-medicate to not feel so bad.
In spite of money and fame, they spiral downward. Mother Whitney would be one such. On the other hand, Eric Clapton is a man who gave up first heroin, then alcohol, to begin living a normal life. Make great music, help others, etc.
There are literally scores of sober entertainers, so alcoholism/addiction is not a foregone outcome. Over 20 years sober include Clapton, Ringo Starr, Elton John, Bonnie Raitt, Paul Williams (singer/songwriter), Bill Ward (original Black Sabbath drummer), etc.