She started the drugs, that was her decision. And her decision to not stop.
If only addiction were such a simple matter. Some people can do tons of drugs and still drop it at any time. Others need only do them once to be hopelessly hooked for life. It depends on a number of biological and psychological factors. Besides, Amy did try to stop, and for a while, she apparently had. She also had other issues, however, which certainly didn't help.
Winehouse's battles with substance abuse were the subject of much media attention. In various interviews, she admitted to having problems with self-harm, depression and eating disorders.[4][5] In 2005, she went through a period of drinking, heavy drug use, violent mood swings and weight loss.[17] People who saw her during the end of that year and early 2006 reported a rebound that coincided with the writing of Back to Black.[17] Her family believes that the mid-2006 death of her grandmother, who was a stabilising influence, set her off into addiction.[17]
In an October 2010 interview Winehouse said she had been drug-free for three years, saying "I literally woke up one day and was like, 'I don’t want to do this any more.'”[158]
A former drug addict has agreed with that.
That only makes him an expert on his addiction, not all addiction. It is not the same for everyone.