I don’t believe that you make self destructive choices unless you are feeling a great deal of pain. Some demons were hounding her and she turned to drugs to cope. Not a wise choice, but a very common choice. Whose to blame? I’d say our whole culture. Not that anyone would go along with that since it means we all have a teeny-tiny bit of the blame for this.
The point though, is not to blame, but to figure out what we can do better. Personally, I think compassion is helpful. I’ve seen a lot of that here, and it’s helped me. It could help many others, too. Maybe it could have helped Amy, too.