A redescription of data does not count as a general theory.

Abstract

Piazza and Deroche-Gamonet (PDG) seek to formulate aframeworkforaddictionsufficientlybroadtoencompassmostdatainthefieldand,notably,thoseproducedbytheBordeauxSchool of Psychobiology to which I also belong. Briefly,according to the PDG framework, the development of addic-tion would involve two unidirectional transitions across threeconsecutive stages of drug use: a first transition from recrea-tional drug use to escalated drug use and a second transitionfrom escalated drug use to compulsive drug use. Importantly,the likelihood that a given individual drug user will make atransition would depend on two types of psychobiologicalvulnerability that are transition-specific and differently mal-leable to drug availability. Specifically, the vulnerability totransition from recreational to escalated drug use would bedifferent fromand more drug-malleablethanthe vulnerabilityto transition from escalated to compulsive drug use.Overall, this is an interesting proposal. However, I wouldnotcallitageneraltheory,butaredescriptionofexistingdata.First, PDG framework does not advance any overarchingtheoretical construct and relies on a shaky theoretical founda-tion. The authors claim to have derived it from a carefulconsideration of both DSM-based and RDoC-like behavioralsymptoms, but how is this derivation made? What are thetheoretical principles and rules involved? How can one de-duce a dynamical multistage framework for the transition toaddiction from a heterogeneous set of static, operational, anddescriptive behavioral criteria? Clearly, something is missinghere. Without further explanation, PDG framework appearsmore as an ad hoc and arbitrary redescription of existing datathan a general theory of addiction. It indeed abounds inunjustified claims. For instance, what does forbid the exis-tence of a direct transition from recreational to compulsivedrug use without transitioning to the stage of escalated druguse? What does prevent a transition to be bidirectional andreversible instead of being unidirectional? Whatdoes excludea stage of abstinence and associated specific transitions andvulnerabilities? Abstinence necessarily precedes recreationaldruguseandshouldeventuallyfollowanyotherstageofdruguse at least in the majority of illegal drug users (Heyman2013). Second, the explanatory power of this framework iscurrently uncertain. At a minimum, one expects from a novelframework to be as good as or preferably better than thepreviousonesinorganizing,encompassing,and/orexplainingexisting data. Whether PDG framework meets this minimumrequirement is currently unknown, however, mainly becausethe authors donot makethe effortto compare their work withthat of others (e.g., Kendler et al. 2012;Redishetal.2008).Third, the heuristic value of PDG framework is low as mea-sured by its inability to generate truly novel and uniquepredictionsand/ortohelpseeandunderstandthingsdifferent-ly. I was at pain to formulate or even identify truly novelpredictions from PDG framework. The heuristic impotenceofPDGframeworkisnotsurprisinganddirectlyfollowsfromits ad hoc descriptive nature.A mere redescription of data is not necessarily a fatal flawand can even sometimes prove to be instrumental in theformulation of a general theory, as illustrated, for instance, bytheearlyhistoryofgeneticsorquantummechanics.However,inthe case of PDG framework, the data themselves are still openfor debate and reinterpretation. First, PDG interprets the clas-sic LR-HR rat model as a model of the transition from recre-ational to escalated drug use. This is inaccurate. It is true thatthe LR-HR model was highly influential in the 1990s andspawned a productive line of research on individual factors