I've touched on this occasionally in my writing. For instance, in "Good Help Is Hard To Find," the supporting character is a drunk and the main character is having a difficult time switching from Evil to Good. One of my unpublished stories, "Pebbles from the River Lethe," is primarily about post-traumatic stress disorder but that arcs into a major thread on addiction. Or threads, if you count the protagonist's early attempts to self-medicate with alcohol.
I look at addiction as an adaptive malfunction. So my sorting process goes like this:
* Is there an underlying problem that you're trying to alleviate? If yes, then you have a valid reason to explore substances or practices to that end. If not, what you're doing is recreational and should be kept at a lower level.
* Is what you're doing causing a problem? If yes, then you need to consider the possibility of quitting and the relative cost. If not, then it's functioning as maintenance and not an addiction.
* Is the solution causing more trouble than the original problem? If yes, then you need to be doing something about that. If not, then at least you're ahead of where you were.
* Can you scale back or stop if you wish to do so? If yes, this is not an addiction. If not, it is, and the advisability of maintaining it depends on the risk/benefit assessment.
* Is there a level at which the benefits may be obtained without much if any negative side effects? If yes, it's maintenance. If not, that's a problem typical of many addictive substances, especially as habituation increases. Many things are functional at one level but dysfunctional at others.
By my definition, an addiction is something that you can't readily withdraw from even if it causes more trouble than it's worth. It's your own adaptive process working against you instead of for you.
This leaves out some things that cause physical adaptation but do not make trouble, such as some maintenance medications. Bear in mind that food, water, oxygen, and many other things are required for life; and some of those can trigger the habituation effect under some circumstances. This also goes against the sometimes fashionable idea that if any substance ever causes a problem, it's an addiction; well, no, if you can stop after a bad experience, that's just a mistake and you learned from it. People do that.
This also includes some things that society customarily excludes from consideration because they are recommended or required. Just because everyone thought it was dandy to smoke for decades didn't make cigarettes not kill people. Same with prescription drugs, it took a long time for anyone to admit that those can be as addictive and destructive as street drugs. So can religion, sex, and all sorts of other stuff. What matters is whether it does damage and whether you can stop; not whether or not something is "respectable."
In speculative fiction, we can look at different things that a society might excuse or condemn, or that might become addictive. Magic, new drugs, alien symbiotes, gods, artifacts -- all kinds of stuff can mess up a character's mind and life. Then we can explore positive or negative ways that society deals with that. (haikujaguar has a wonderful story about social response to addiction.) Sometimes that reveals new ways of thinking about a problem or looking for solutions.
What are some of your favorite stories that touch on this topic?