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Wise RA, Koob GF.
“The Development and Maintenance of Drug Addiction”.
Neuropsychopharmacology. 2013 Oct 6.
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Abstract
What is the defining property of addiction? We dust off a several-decades-long debate about the relative importance of two forms of reinforcement—positive reinforcement, subjectively linked to drug-induced euphoria, and negative reinforcement, subjectively linked to the alleviation of pain—both of which figure importantly in addiction theory each of these forms has dominated addiction theory in its time. We agree that addiction begins with the formation of habits through positive reinforcement and that drugopposite physiological responses often establish the conditions for negative reinforcement to come into play at a time when tolerance, in the form of increasing reward thresholds, appears to develop into positive reinforcement. Wise’s work has tended to focus on positive-reinforcement mechanisms that are important for establishing drug-seeking habits and reinstating them quickly after periods of abstinence, whereas Koob’s work has tended to focus on the negativereinforcement mechanisms that become most obvious in the late stages of sustained addiction. While we tend to agree with each other about the early and late stages of addiction, we hold different views as to i the point between early and late at which the diagnosis of ‘addiction’ should be invoked, ii the relative importance of positive and negative reinforcement leading up to this transition, and iii the degree to which the specifics of negative reinforcement can be generalized across the range of addictive agents.
What is the defining property of addiction what comes first and what follows? Is positive reinforcement sufficient to establish an addiction? Or must negative reinforcement come into play before an individual is past the point of improbable return? Here we have little agreement. The continuing debate over whether cannabis is addictive the historical debate over whether nicotine is addictive and the emerging debates over whether compulsive gambling, video gaming, and sexual behavior are addictive all result from the fact that there is no widely accepted scientific definition that allows us to identify the point at which addiction emerges from a casual or ‘recreational’ habit. In the first place, the committees of clinical experts that set forth diagnostic criteria for such groups as the American Psychiatric Association APA and the World Health Organization do not offer a scientific definition Schuckit, 2012 in the second, there is little agreement between Edwards, 2012, or even within, these scholarly groups O’Brien et al, 2006. Instead of ‘addiction,’ the Diagnostic and Statistical Manual of Mental Disorders DSM like Koob in his first quotation below stresses the term ‘dependence’ also a fuzzy term, one that sometimes refers to ‘physical’ dependence and sometimes to questionably defined ‘psychic’ dependence. Thus, not surprisingly, the reliability of diagnosis using the DSM—the authority on which new animal models have recently been based Deroche-Gamonet et al, 2004 Vanderschuren and Everitt, 2004—has been poor and is getting worse Hasin et al, 2013. In truth, in our use of the word ‘addiction,’ we share the sorry condition articulated by Humpty Dumpty: ‘When I use a word it means just what I choose it to mean—neither more nor less’ Norman White used this quotation earlier in a related context White, 1989.
There are good reasons that the word ‘addiction’ does not appear as a diagnostic category in the DSM. It simply means different things to different people—even to different experts including Koob and me. When some people think of addiction, they think of the condition of addiction, the condition of someone at the stage of asking for treatment or of causing problems for others: someone who has progressed to the later stages of this progressive process. This is a useful clinical perspective it focuses on the variety of symptoms that require attention and for which medications might be developed. Others, however, are thinking of the process of addiction, looking for the necessary and sufficient conditions for the development of addiction, the transition from volitional to compulsive drug use. This is a scientific perspective, probing the differences between cause what comes first and consequence what follows. The first use of the word differentiates the extremes of addiction: it differentiates the end points from the drug-naive starting point. The second seeks an intermediate point, a point of no return, a point partway down the slippery slope of increasingly compulsive intake. It is problematic for those interested in process that addiction does not suddenly appear like a fever or a boil at some relatively well-defined and finite point along the way. Rather, it begins to grow with the first reinforced response and strengthens incrementally thereafter, even in the case of a classic addiction such as opiate addiction McAuliffe and Gordon, 1980.
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