During my brilliantly misspent youth, I spent some time at a drug and alcohol rehab. (I was recently reminded that when I say that, I should be sure to emphasize that I was employed there, rather than being a guest of the facility.) I was on the adolescent boys' wing, and this was not, let us say, an ideal job. The management was atrocious, the pay was abysmal, and the work was unrewarding. However, it allowed me to work nights - and night shifts were usually slow, so I could study. And there were some interesting bits; I learned more about Twelve Step programs than I ever wanted to know.
That was also the first time I'd really done any serious thinking about the nature of denial and the role it plays in human behavior. Denial can be a problem for anyone; for addicts, it's one of the mechanisms that allow people to continue self-destructive activities long after the point where any objective assessment would tell them to stop. As a result, learning to recognize and overcome denial is a large part of the treatment process.
So how do you tell if someone is an addict? The primary distinction is whether or not the person can stop. For drinkers, one test is whether you can cut yourself off after two drinks. (This leads to numerous, and often amusing, stories about ways people have tried to fudge the test; for example: "He only had two drinks, but each of them was a twenty-ounce mug that was half full of rum!" Denial and rationalization in action...) Another way to look at the question is whether the behavior is causing trouble in other areas of a person's life. Is drinking (etc.) causing poor performance at work or school? Is it leading them to make bad decisions that get them into trouble?
It's probably worth noting that addiction is often part of a larger pattern of destructive behavior. This often makes cause and effect hard to determine, and also means that a lot of treatment focuses on changes in lifestyle: finding new hobbies, learning how to make better friends, and like that.
Anyway, the problem with that kind of assessment is that you have to know what's going on in someone's life. You have to see their behavior in order to evaluate it. That takes time, resources, and access to the person. Counselors, as a general rule, don't have any of that.
So if you've been sent to rehab (and the adolescents were almost always sent, by either their parents or the court), there is essentially no way to establish that you are not an addict. If you try to say that you aren't, the counselor will automatically assume that you're in denial, which is clear evidence that you're an addict. If you try to lay out the specific details of your behavior, they will assume that you are rationalizing, downplaying, or lying outright about your usage - because, again, that's what addicts do. Pretty much anything you say, do, or offer just provides further proof that you're an addict.
This is the best example of a real-world Catch 22 that I've ever encountered. It's also exceedingly frustrating to deal with (but don't get angry about it; then you're acting out, which is - again - further proof of addiction). Hell, it was frustrating to watch - because I knew that inevitably, the facility was going to wind up with some boys who didn't actually need to be there. There was no way, in that system, to account for the fact that the world is full of people who simply aren't addicts.
I bring this up because it's a very similar dynamic to the one I mentioned in a previous post: the idea that if you aren't a Christian, it must because you've never heard about Jesus; or, if you're an ex-Christian, that you must never have been exposed to True Christianity - you were never really a Christian in the first place (I John 2:18-20). I've even encountered the (rather daft) argument that since the Bible says people will leave the faith (1 Timothy 4), the fact that people leave the faith is actually proof that the Bible is true.
The problem with both of these views is that they narrow down the available options, creating a sort of logical trap. The only way to disagree with them is to reject the validity of the whole setup. Depending on the power dynamic, that may or may not be possible.