(The following is from an email exchange with my friend, Hannah. Thanks, Hannah, for getting me inspired!)
I think that both addiction studies and decriminalization arguments benefit enormously from what the data says, and we're not really getting novel data so much as we're simply listening to what the participants are saying and trying to act as translators for everyone else. What we're saying is that people aren't waking up one day, typically as young teens or tweens, and saying to themselves, "I gotta get some illicit narcotics." It's not the case that people begin using drugs because they are seeking the drugs or the effects of ingesting the drugs.
Rather, the drug use comes to them. The vehicle of transmission always is a social medium: a family member introduces the practice of drug use to the child; a new kid at a new school can't fit in with anyone but the kids that are using drugs and in so hooking up with these kids the new kid now has something that makes him popular; maybe it's a summer job and the teen's boss told her that using meth will enable her to get more work done in a day.
Right now we have this emphasis on addiction as a personal disease (this is when the model for addiction is most coherent, there are, of course, many informal definitions that influence policy makers). It may be true that there are people that are physically dependent upon substances of abuse, where their body chemistry simply requires a supplement of dopamine in the brain; but, the truth of the matter is that these chemically dependent people are, at best, 10% of the people in all of the literature on addiction.
One can guess that a majority of drug users are never even included in the study of drug use (maybe because they only used once or twice); the nature of drug use networks is such that they are a hidden population because drug use is illegal. The result is that most people that are included in the addiction literature are not quite accurate representations of the whole drug using population; they're not accurate representations because the primary organ in society that senses drug users is the criminal justice system (again, because drug use is a moral crime). This situation has serious ramifications on society.
One result is that we continue to have a terrible sample population upon which to base our theories of drug use and addiction. This means that we have really unintelligible models for understanding drug use and addiction (such that even in the best case scenario, where people accept that addiction is a disease, the disease is not really a physical ailment but a pathological inability to make moral decisions - just to be clear, morality has no biological basis, it's strictly a mental capacity). The last element of our trifecta, then, is that we have really terrible policy toward this phenomenon called drug use and addiction. The policy seeks to (this is really when policy is at it's most coherent, which is of course rare)...seeks to balance the impossible: that we can develop a pill (NIDA and NIH are the two agencies that really pursue this most aggressively) that will cure addiction, or maybe develop some biological mechanism that would predict who will develop a chemical dependence - and let's keep in mind that at best that would be 10% of the minority of the population we've ever encountered. And on the other hand our current policy tries to develop the best moralistic (morality formalized and codified is law) solution to the problem - to be clear the problem is a moral one, a failure to choose the right thing.
Why won't these work together? Because there is no biological basis in making choices, if there were we could make a pill that enhanced decision making, right (and this is how some people in the field talk); so if we could make a pill that helped you make better choices we'd then have to concede that free will is not real because what we thought was reasoning and rationality was really a math equation. Of course, if free will doesn't exist, then we really can't put nobody in jail for making bad choices. Maybe we could put society on trial for not giving these people access to the substances that enable them to make the right choices, but this is clearly nonsense and an undesirable view (that there is no free will).
So our paper is trying to point out that this emphasis on morality and biology is missing out on the big picture: that people use drugs and they do so primarily in social settings. 99% of the time substances of abuse are consumed in intimate networks (i.e. family settings like a cook out with beer, a group of drug buddies in the fraternity, coworkers on the highways delivering groceries to grocery stores); only in the worst case scenarios, at the end of the drug using trajectory, does the criminal justice system encounter drug users: when they're stealing to get the drugs that former friends will no longer lend to them, when they're so consumed with drink that they no longer can live with their families, and so on.
If you look at drug use networks you see that they are very conservative: they are completely dependent upon mutual trust. Once someone breaks that trust, by ceasing to reciprocate in one form or another in that relationship (i.e. doesn't pay for the drugs in a timely manner, drank the whole bottle themselves, or quits using the substance that they once shared using and so now suspiciously might be a narc), this is the moment when drug use patterns fracture and we can predict how likely one is to relapse or cease to use substances of abuse.