Excerpt: Doctors in many parts of the world — including Canada and some European countries — prescribe more powerful opiates than their peers in the United States. In England, if, say, you get hit by a car, you may be given diamorphine (the medical name for heroin) to manage your pain. Some people take it for long periods. If what we’ve been told is right, they should become addicted in huge numbers.

But this doesn’t occur. The Canadian physician Gabor Maté argues in his book “In the Realm of Hungry Ghosts” that studies examining the medicinal use of narcotics for pain relief find no significant risk of addiction. I’ve talked with doctors in Canada and Europe about this very issue. They say it’s vanishingly rare for a patient given diamorphine or a comparably strong painkiller in a hospital setting to develop an addiction.