Sure it's possible to try heroin just once. I've known people to try heroin just once and then never touch it again; and those who do pick it up again may not be addicts necessarily.
I'll never understand this wacky sort of benchmark we apply to heroin where once you try it a second time, you're an addict. How ridiculous is that? I mean, consider this: If you give your friend his first line of dope, and he likes it, and he wants to give it another try at some later date, then is he an addict? Is it a habit? Is it already a problem? Is he addicted, playing with fire, well on his way to becoming a junkie?
OK, so then if you give your friend his first drink of alcohol and he likes it, and he wants to go out for drinks next week... alcoholic? Why not?
I guess that my point is this: Why is heroin and heroin addiction so vastly different from alcohol and alcoholism? I took my first drink, and I wasn't sure where it would take me. I could have become a full-blown alcoholic, and I could have become a weekend, bar-hopper or club-goer. I could have hated it, thrown up, and lost all interest in it completely. It could have gone a million different ways, but I took that first drink and I found a place for alcohol in my life away and apart from the other, more important things in life (work, family, etc.) Do I drink? Yes. How often? On average, maybe once or twice a week. Do I drink more on occasion, from time to time? Sure, sometimes I drink more heavily than other times. Other times, I don't drink at all. Am I an alcoholic? I don't think so, no.
I tried heroin for the first time, and, like alcohol, an infinite number of outcomes were possible. I could have hated it, thrown up, and never tried it again. I could have fallen head-over-heels in love with it and become a total purse-snatching junkie. Instead, I liked it, and I found a place for it in my life. Do I blow dope? Yes. How often? A few times a week. Do I blow more dope on occasion than other times? Sure, sometimes I do more dope and sometimes I do less dope. Am I an addict? Honestly? No, I don't think so.
And then, of course, others will retort, "Give it time!" But why, and how? How is it that using heroin will undoubtedly turn into some out-of-control, full-blown addiction 100% of the time, and yet drinking alcohol occasionally can be pretty well maintained for one's lifetime? It will never make any sense to me...