The 5-fold Pathway to Addiction
- posted by Jim Leitzel @ 9:35 PM

The Economist reports this week on a recent article in Computational Biology, one of the journals associated with the Public Library of Science -- hence the article is freely available on the web. The article set out to find the neuro-molecular pathways that are common to alcohol, nicotine, cocaine, and opiate addiction. The authors took a meta-analytic approach, combing the existing research database for articles reflecting upon the issue -- and they came up with something new. They identified five neuro-pathways that seem to be common to the four types of addictive substances. Two of these pathways were not seriously under consideration in the past, if I understand correctly, for being involved with addiction. The authors then went one step further, modeling the interactions within these five pathways. The model suggested various types of positive feedback, which would seem to be consistent with the loss of control associated with addiction. (Though perhaps some sort of chemical reversal of this mechanism could lead to a quick recovery, my untutored, neuro-naive self asks?) Is their diagram of the feedback mechanisms one of the keys to understanding addiction?

The methodology in this article is striking. One venerable view of economic productivity associates it with making stuff, with production. Often merchant behavior, trading activity, is seen as somehow inferior or disreputable, even when production is held in high regard. Economists tend to a hold a different view, however -- a good is valuable only if it is at the right place at the right time, so merchants are as productive as they are indispensable: manufacturing without effective distribution is not productive. The analogy I see with the Computational Biology paper is that research, especially neuroscientific research, might be thought of as consisting of running experiments. But unless someone sifts through those experiments to extract and combine the information, the experiments themselves might not produce usable knowledge. The Economist article concludes with the following observation:

And this study also shows that the old cry “more research is necessary” is not always true. Sometimes all you need to do is look at what you already have in a different way.

I would have put it slightly differently: "More research is necessary" remains true, but research can consist of such meta-analyses, too. (Maybe The Economist was trying to avoid rhyming?)

Labels: addiction