I’ve seen several things recently that have argued that drug abuse is closely connected with bad environments, especially abuse as a child. This anecdote is a great summary of why that is:
In the 1970s, Vancouver psychology professor Bruce Alexander noticed something odd about this experiment. The rat is put in the cage all alone. It has nothing to do but take the drugs. What would happen, he wondered, if we tried this differently? So Alexander built Rat Park, a lush cage where the rats had colored balls and the best rat food and tunnels to scamper down and plenty of friends: everything a rat could want. What, Alexander wanted to know, would happen then?
In Rat Park, all the rats obviously tried both water bottles, because they didn’t know what was in them. But what happened next was startling.
The rats with good lives didn’t like the drugged water. They mostly shunned it, consuming less than a quarter of the drugs the isolated rats had used. None of them died. While all the rats who were alone and unhappy became heavy users, none of the rats who had a happy environment did.