A rather grim book. Dalrymple worked for years as a prison doctor and at a hospital in some of the worst slums in England. So he knows whereof he speaks.
And there's no denying that the addicts he sees live grim lives. He observed to many of them that it was clear that freedom was to them a concentration camp: whenever they were sent to jail, they would be miserably malnourished, even starving, and in jail they would recover their health -- only to return months later in the same condition. None of the addicts disagreed.
But -- both the ease of addiction and the pains of withdrawal are commonly grotesquely exaggerated, and he marshals an impressive array of studies to show it. To be sure actual, physical withdrawal has some symptoms, but none serious. He objects to the standard description of withdrawal as like a bad case of flu, because in fact flu kills people, which opiate withdrawal doesn't. He also points out the wickedness of justifying the crimes the addicts commit on that ground; how many people would commit burglary to avoid a standard case of flu? Also, he took to asking addicts when they first went to jail, and at a different time, when they had first used heroin. Sixty-seven out of a hundred had taken heroin later, and eight had taken it for the first time while in prison. Given the number of crimes it takes to get to jail in Great Britain, they were hardened criminals by that time.
Then he discussed the literary works on which the romanticized view of heroin rests, and the flaws in it. Coleridge, for instance, was describing not opiate withdrawal but alcohol withdrawal, which is much more serious. (But being a drunk sound so much more romantic.) Others were lying, about how they started, and may even admit that it takes time, and regular daily injections, to get addicted, while in other places claiming it was easy.
This leads into the impact of such romanticized views on the bureaucracy to deal with the addicts, and the damage it does. Which is not pretty. He recounts having tried to bring up the problems only to be charged with trying to undermine the consensus.
Grim stuff. Interesting reading, still.