Really sad how addiction got such a hold over a young girl. I'm sure Ch4 made a documentary with DW years ago where she said she was offered her first line in a club at 14, after she took it that same night she bought a vodka & orange and 20 B&H (cigarettes). If I remember correctly she was almost saying before that night she hadn't touched an alcoholic drink or smoked but then everything came at once.
From what I've read her family are supposedly nice, good people, but who the hell lets their 14 year old go clubbing? Not a one off, sneaky "I'm staying at a friends house" occurrence, she was quite a regular so her parents must have known. Maybe they didn't mind if it allowed her to schmooze and increase her chances of paid acting work?