I didn't think Dr. Zangwill implied either of the people she mentioned where drug addicts. She is simply trying to raise awareness about the issue.
Although doctors should ask what else a patient is taking, no one is perfect. That's why it's important to drive your own health care which is what this site is all about. Pain meds are dangerous and so are sedatives if not carefully watched. I absolutely refuse to take them. I have not been in a situation where I felt I needed them but I have found SOME doctors and dentist all too willing to hand out a prescription for them without asking if I want them.
The best thing to do is find out the source of the pain or the cause of the sleeplessness or anxiety and treat that. If the drugs are needed interim then they should be closely watched.
I have noticed that many of my friends will keep their spare pain meds or muscle relaxers or sleeping pills for future use. They have pain, they pop a pill. I feel that is so dangerous! I have committed to myself not to use any drugs at all unless they become absolutely necessary. The less drugs I have used (including tylenol and advil) the better I have felt.