Over recent years, about as many frameworks for understanding addiction have been proposed as there are researchers working on the topic. Redish et al. take the ecumenical path and suggest that all frameworks are at least partially right and can be accommodated within a larger theory of decision-making. There are many paths to addiction, as there are many ways this cognitive system can break.
The first difficulty with what the authors propose is that it does not help in predicting, diagnosing, or treating various addictions. They are very clear that a variety of genetic, environmental, social, behavioral, and presumably neural factors lead someone to addiction. Their model does not make any comments on sorting out which factors are relevant under which circumstances. But being able to predict who is likely to become addicted when is probably the biggest lacuna in addiction research today.
In addition, Redish et al.'s proposal offers no clues as to how one should determine which systemic vulnerability or vulnerabilities are tied to which addicted individual. Because different addictive substances and behaviors affect the brain in different ways, we already know that there is much variation in the biochemical specifics of addiction. What we do not know is how to identify the vulnerabilities a particular individual might have, nor do we know whether the vulnerabilities are mutually reinforcing.
Finally, although the authors suggest that one should tailor treatment to the specific breakdowns one finds in the decision-making system, this is already what health-care providers do. We already know that addiction has multiple facets, which is one reason treatments are rarely completely successful. We already know that one size does not fit all; indeed, one size does not fit one in most cases. We need multiple interventions at multiple levels to effect changes in most addictive behaviors.
While the authors have cleaned up some of the laundry list of attributes contributing to addiction, they have not shortened the list, nor have they developed a complete list. In other words, their theory of addiction as vulnerabilities in the decision-making process is not sufficient for understanding addiction.
The second difficulty is that the vulnerabilities they identify as contributors to addictive behaviors are not definitive of addiction. Overvaluation in the planning system happens on a regular basis in most people's lives, as does the incorrect search of situation-action-outcome relationships, misclassification of situations, and over-fast discounting processes. For example, if people are asked whether they would prefer a fifteen-cent Lindt truffle or a one-cent Hershey's kiss, 73% choose the truffle. But if we ask people whether they prefer a fourteen-cent Lindt truffle or a free Hershey's kiss, only 31% choose the truffle (Ariely Reference Ariely2008). In the normal course of our daily lives, we tend to overvalue free things. These sorts of so-called vulnerabilities in our cognitive processes are well known. They suggest that we are not perfectly rational and that we make errors in our behavioral choices. But these facts are true of all humans, not just those with addictions.
Even the vulnerabilities that intuitively might seem to be tied more closely to addiction – moving away from homeostasis, changing allostatic set points, and euphoric “reward-like” signals – are part of many non-addicted people's daily lives. Patients with depression, schizophrenia, autism, and post-traumatic stress disorder, to name a few conditions, could all be described as having vulnerabilities in their affective reactions. So do people with stressful lives, with new loves, and who are coping with tragedy. The point is that a malfunctioning or oddly functioning decision-processing system is a very normal aspect of everyone's lives. I would argue that it is part of what makes us human. But more importantly, these vulnerabilities are not necessary for addiction.
To summarize my main point again: Although the authors have pulled together a large number of approaches to understanding decision-making and common errors in cognition, they have not really developed anything that helps us predict, treat, control, or understand addiction. They are surely correct in claiming that addiction is multifaceted and probably more akin to a syndrome than a genuine disease. But fully grasping that multifaceted syndrome still eludes us.
