Alrighty, I'll bite, sort of, on drug abuse policy issues. I'm triggered by a recent comment responding to a guest post over at the blog of some dude who's famous mostly as the brother of one of our most insightful commenters around here. Before I get to my ish, you might find the dueling Drug War perspectives of the aforementioned guest poster, Radley Balko (agin' it), and David Freddoso (fer it) over on Culture 11 interesting.
Commenter Bachelon wrote:
I forget where I read it, but I've seen studies that have shown that while more people might try something once, the amount of people who would use regularly (and the rates of dependence and addiction) would remain the same.
So one wonders if anyone (anyone, anyone....Bueller?) has any toe holds on what those might be? Authors? Drug in question? Anything?
The reason I wonder is because it is not clear that one could ever really test this, save with a decriminalization effort. Maybe Canada or the Netherlands for cannabis? The US Prohibition era is useless because there are very few data.
Also, this comment is confusing "amount" (the number of people using a drug is stable) with the population "rate" (numbers of people increase with the exposed population). Two entirely different matters. Me, I suspect if you change the exposed population significantly you will most certainly not remain at a stable number of addicts. On the other hand, I also predict that the increase in addicts will undershoot the increase in exposed population on a rate basis.
These, and the opinions advanced in the two articles from Balko and Freddoso, are just predictions. Hypotheses about what would happen if there were major changes in drug policy. Hopefully advanced in a testable way, backed by some recognition of the available data and not just some seat of the pants estimate influenced by the predetermined outcome.
In terms of my first prediction, well, I've often referred critically to the fact that almost every animal model of addiction is predicated on 90-100% of individuals expressing the phenotype. With enough opportunity to self-administer intravenous cocaine or heroin, almost all of the rats will acquire the behavior. Meaning pressing on the lever that gives a drug infusion more than on a lever which delivers nothing or a saline infusion. It gets more complicated but that will suffice for now. My critique of the animal models is based on the fact that even among the population of humans exposed to a given drug (say, i.v. heroin), not all will become dependent. So the models have some conceptual limits. Nevertheless they do tend to suggest that with enough exposure to a drug (under the right circumstances) virtually everyone will become an addict. This suggests that if we lower the barriers to entry by making recreational drugs legal and easily available at your local head shop (or more likely the neighborhood likkerstore) the number of addicts is going to increase.
Now why do I predict an undershoot of the current rate? I'm out on more of a limb on this one but it stems from my acknowledgment of individual susceptibility to develop a liking for a given drug or even a propensity for impulsive behavior that generalizes across drug classes. In both human populations and animal models, I will note, there are going to be significant differences in who gets to addiction most easily or sooner. I'll suggest that the population of humans who are willing to try illegal drugs in the current environment have an increased percentage of those that are susceptible to dependence. As a corollary, I hypothesize the hypothetical population that won't try a drug solely because it is illicit and/or not trivially available is less rich in phenotypes that will lead to addiction.
Like I said, just a couple of hypotheses.
As always, I recommend perusing the Monitoring the Future publications (view easy summary figures and tables from 2008) and looking at long term trends in use patterns, attitudes toward drug use ("how safe is it to try once, use regularly", etc) and adolescent reports on the ease of procuring various drugs of abuse.