The gateway theory is that "soft" drug use is an independent risk factor to using "hard" drugs.
Your theory is that the personality of a hard drug user predicts they will use softer drugs.
That is the opposite of, and parallel to one argument against, gateway theory.
I know, I'm aware of the basic idea and was kind of making fun of it, but in a way I think you could probably see what I am saying.
I mean, the concern seems to be, that if a person takes one drug it will "lead" to them taking another.
I don't think it should really matter if it's a harder drug "leading" to a softer one, it honestly IS kind of messed up to think that anytime you tried a drug it might be likely to "lead" to ANYTHING else.
If I am considering trying something, I do not want to have to predict how many other drugs it may lead me to try and whether they interact with anything else I take, etc.
I remember reading and watching the Basketball Diaries when I was a teenager and Jim Carroll supposedly said that he really did try Heroin because he thought it was the "weak drug" and thought Marijuanna was the one he should avoid.
So in his case, if he tried heroin and lived through it, at that point he'd probably not be afraid to go back and try everything else less dangerous right?
If ANY drug is likely to lead to any other, it would be a "gateway" but really, it's all bullshit.
But honestly, I will 100% agree with everyone who says alcohol is their "gateway drug".
When I drink I want to do EVERYTHING I'm telling myself I shouldnt' be doing whether it's weed or coke or just acting irresponsible.
Those substances which decrease inhibitions are the ones where any argument can actually be made to them influencing using anything else while under the influence.
Weed on the other hand, hell, if I get high in my house it's hard to "influence" me to get up off my couch haha.