Have you ever seen a young junkie prostitute? Talk about death in life! Seriously, I think a lot of the stories are centered around control-freak drugs and similar magical techniques. Such techniques are, by definition, dark side. Don't go to Knockturn Ally, friends! Not worth the karmic costs.
The problem is, it has never been difficult to convince a person that they would die without a given drug. They do get sick if they don't get it, so telling them they will die is not that difficult. Then you have power over them as you have power over their drug supply. Anyone who has even flirted with addiction, or who has the brains to recognize it in others without having to experiment with his or her own body, knows that addiction is not something you want. It's something you end up with for being stupid, and not maintaining self-control.
As with the nastier drugs, there are other dark magic ways to bend another to your will, and some of those have been represented by the "undead," if you will [although there is clearly overlap here]; those who walk as though alive, but are in fact vacant shells. No soul. So there are all sorts of good reasons to recommend against playing with, let alone working with, dark magic.
In Harry Potter's world's vocabulary, we are talking one of the unforgivable curses: the imperiatus. The bending of another's will to your own, thus depriving him of what makes him human, is quite literally, in my opinion, unforgivable. But then, I have always needed rather more forgiving than I have been happy to give out. Something about not wanting to suffer fools gladly.