The study described here seems to have particular relevance to the US, given the runaway rate of prescription of opioids, and the overdoses therefrom:

On another occasion a patient, a heroin addict, accused me of murdering him because I would not prescribe diazepam for him. In actual fact, I believed that precisely the opposite was almost the case: that if I prescribed for him what he wanted, his chances of dying by overdose, intentionally or unintentionally, would be much increased.

A paper in a recent edition of the British Medical Journal suggests that I was right.