Regular readers of the blog will be familiar with much of what’s currently known about how best to treat people with drug problems. Unfortunately, because so much research on that topic originates in North America, European policymakers can sometimes be left in a tricky position: either they assume that research conducted elsewhere applies similarly their side of the ocean (a justifiable assumption in some cases, to be sure), or they throw their hands up in exasperation. This problem is much less acute when we’re dealing with research on specifically medical interventions, where European research is up-to-par (and indeed superior) in many areas. But when we’re dealing with the criminal behaviours of people with drug problems, much less research comes from Europe.
Some colleagues and I recently published a study in the journal Psychology, Crime & Law that hopefully goes some way towards addressing this problem (link here for those with a journal subscription; otherwise, feel free to email me if you’d like a pdf version). We conducted a meta-analysis on the effect that treatment programmes applied to drug abusing offenders had on crime, health, and drug use outcomes. The hope was to collect everything on the topic that would give a sense of the evidence base, as long as it emanated from Europe.
After combing through nearly 40,000 titles, we found only 15 studies that were sufficiently rigorous to exclude common threats to validity (e.g., roughly equivalent comparison groups, etc). Moreover, those studies came from only six countries (eight were from the UK). Even within Europe, there’s a tremendous regional disparity in who’s doing the research on which other countries rely.
The results showed that there was a clear positive effect of treatment on criminal behaviours, illicit drug use, and physical health. Assuming a base rate of reoffending of 50%, the results corresponded to an average reduction of reoffending of 37% in the treatment groups compared to the control groups. Results were somewhat more mixed for psychological health outcomes, and for illicit drug use after we disaggregated the outcomes based on particular types of drugs.
One of the main conclusions of the paper will not be news to those who follow what others on this blog have been saying for years. If we can persuade policymakers to endorse the proposition that the quantity of drugs consumed might not need to change in order to 1) decouple the drug-crime connection, 2) provide a safe, stable position in which to manage other complications arising from someone’s drug addiction, then we might be able to make serious progress.
For those who wondered whether European evidence points in a similar direction to North American research, this paper suggests that it does. In fact, the results of our meta-analysis are even more positive than what was observed in previous reviews. However, this should be taken cautiously, both because of the erratic properties of small sample sizes, and because of the over-representation of evaluations of pharmacological substitution treatments in our sample (which generally show particularly good effects).
If you’d like a copy of the paper, but you don’t have journal access, you’re welcome to email me at [myfirstinitial][koehler][@][berkeley]“dot”[edu]