A lot of ground has been covered in this thread. I thought I'd just add a few tidbits for consideration: 1) There was a really good expose in the New Yorker a few months ago on how Big Pharma, in particular a specific family-owned company that marketed Oxycontin, convinced the medical industry to start freely prescribing opioids, using paid shills to publish papers that alleged that pain management was not being well done, and that the risk of addiction was way over-rated. There was a dramatic increase in opioid prescriptions which led to the crisis our nation faces today, and it was driven by greed. Even when the data started coming in, the companies making loads of $$ did their best to supress/discount/cloud matters so they could keep raking in the $. 2) There are genetic predispositions to being addicted to various substances. They are well documented even if the genetic and metabolic details are still poorly understood. But, for example, Big Tobacco knew that they needed to get every kid to try it before age 16 or so, because after that the odds of even trying it wentway down. They also knew that there is a bell-shaped curve. All kids cough and almost vomit when they first try it. A bunch quit right there. But depending on how cool it is to smoke, a lot of them soldier on until they start to actually like it. Even then, only a small percentage get really hooked to where it is not just mentally but also extremely physically difficult to quit. Big Tobacco knew that only about 10% or less of humans have a strong genetic predisposition to getting severely hooked, but that as long as they could capture every one of those customers they would always make a lot of $$. Similarly, research has shown really dramatic differences in how certain segments of the population respond to food and alcohol. Rather than assume every obese person should just cut back on eating and that they are weak if they can't manage to do it, it may turn out that the way their limbic system and metabolism responds to food is significantly different from how your system responds. I've always been skinny, and my sister has always been chunky. It doesn't matter how much we eat or don't eat. My body's set point is to being skinny; hers is towards being chunky. Lots of Vietnam soldiers used heroin while in country. It was a way of self-medicating and dealing with an extremely difficult situation. Most of them were able to go cold turkey when they came home. But some of them were hooked and hooked hard. Could it be that they had a slightly different brain/body response to opioids that made it harder for them to quit, just as some find it easier to quit tobacco than others? 3) That said, of course there are environmental factors as well. Most people who go down this road have a hole in their soul somewhere, usually created by something less than a happy family. My first cousin who is more like a brother has a history of addiction. He told me that the hardest thing is finding a way to fill up that hole. How to feel at peace when stone cold sober. If you're a "normal" person, you feel pretty good when you're stone cold sober, and partying is kind of a novelty thing to do once in awhile. But for an addictive person, they feel in agony when they are sober and need something to fill up the hole-- and many will try almost any drug just to escape the feeling of being sober. He grew up in a family with five siblings. He was the only one that became a substance abuser, but none of them came out of their upbringing without various issues and other dysfunctionalities.