I remember this dev saying that drug addicts prostituting themselves is not common and not how it happens IRL.
Sure, not all drug addicts do it, but many do. I live in a really small town and I know a girl who does it, and she does it for VERY cheap(and she's a looker, could be earning a lot of money doing highly paid escort jobs but is so desperate that she sucks taxi drivers dicks for a fix). Now imagine in the big cities.
And that's not even the worst thing they do. I've seen people kill their own parents because they didn't want to give them money to buy more drugs. Many(if not most) steal everything in their house when they run out of money to buy more drugs and get very aggressive when their parents or relatives call them out for it.
Honestly, I kinda hate people who think their personal experience is the universal truth. In this case it's even worse because it couldn't be further from the truth. That's one of the reasons that kept me from playing this game to this day. I might give it a try in the future though.
I'm speaking about "hard" drugs by the way. This girl I speaked of is a crack cocaine user, but heroin(which is said in the title to be the drug they're addicted to) isn't much better.
The behaviour obviously differ from drug to drug because each one has its own addiction rate(with crack and heroin at the top). Although, many addicts start at "weaker" drugs(like Marijuana) and go up in the ladder progressively as they begin to develop resistance.