Like lots of folks I drink a bit, and I smoke the occasional celebratory cigar. I'm fortunate to not have found myself addicted to anything though (that I'm aware of at least).
However, I have family members who have deep addiction problems. Life affecting. One thing that I've noticed is that even when they get off of the substance, the addictive personality traits are still there -- years later.
One of my relatives, for example, managed to get herself off of drinking and smoking completely and was in counseling. The addictions, and the kinds of behaviors that come with maintaining addictions (all kinds of dissociative, anti-social, manipulative weirdness) were ruining her life. Strange thing was, after removing the substance, the behaviors persisted.
Many months later, after quitting drinking and smoking, we found that she was latching onto other activities in an addictive way. For example, she found a puzzle game on her phone that she would play obsessively* -- forgetting to eat, sleep, show up for work, having basic human interaction and even requiring physical therapy at one point for the muscle strain of sitting in the position to play the game for hours on end. Crippling physical pain wasn't even enough to get her to stop -- it was what was providing her "fix". She would sit, literally for days straight and play it. Counseling eventually got her to recognize this addiction, but it was harder for her to stop since she had her phone on her at all times.
Then one day she stopped and we all breathed a sigh of relief -- she started sending emails again and generally became more communicative. A few weeks later the behaviors started again, but it wasn't with her phone. Turned out she had just found a computer game she liked more and switched off the phone game.
Today she manages a bit better, but she went through a smoking binge for a while. She's "quit" again, but now just habitually chews nicotine gum. Apparently the nicotine helps keep her off of other more destructive behaviors (like playing phone games obsessively). When she feels stressed, she just chews some nicotine gum and that seems to get her through the craving. She's back working a regular job now and doing okay, but the idea that she'll find some other, better, satisfier, scares everybody.
* - obsession is outright scary when you see it in another human for real. It makes a mood swing look like a flat affect. A person who's addictively obsessed with something is almost feral, operating on instinct -- except with human level brain power to alter their environment to maintain the obsession.