ADDICTION AND THE SEARCH FOR INTEGRATED THEORY
2004-12-01

A lot has happened since the findings of Olds & Milner (1954), which represented a milestone in neurobiological addiction research. Year after year, interesting new studies are being published, each of which can contribute to our understanding of addiction. At present, the models such as biologically determined dysfunction, disposition and neuroadaptation coexist in the literature. In this context, the efforts of Lubman et al. (2004) to bring together numerous findings—neuroadaptations and sensitisation of the dopaminergic reward system, evolution of drug cues and malfunction or dysfunction of the inhibitory function—and to create an integrated model are admirable. The authors explored whether compulsive behaviour is a result of dysregulation of inhibitory control or an overregulated activating and reinforcing system. We must admit that our limited understanding of addiction contributes to weaknesses in current neurobiological research. The discrepant conceptualisations of addiction, particularly our predominantly syndromal definitions found in DSM IV and ICD 10, complicates research population selection, and may thus conceal important etiological differences within an ‘addiction’ population. Ultimately, the complexity of addiction research may not only stem from our inadequate understanding of possible interconnections but also from the idea that addiction may be the final outcome of various pathogenic mechanisms. The multiple pathways hypothesis may explain why findings from animal research may not be applied successfully to human behaviour. The fact that addictive behaviour is expressed in the context of widely differing psychiatric disorders, may be an indicator of the multiplicity of underlying reasons. These observations then beg the question, what is the purpose of neurobiological research? Is it just developing an animal model of addiction or does it aid in the development of new therapies for addicted humans? Do the results replace a moral model of addiction with scientific information that may pave the way patients shed feelings of guilt, thus paving the way for successful treatment? The authors drew an insightful connection between the neurobiological results concerning the inhibitory system and therapeutic strategies which may address patients’ ability to cope with the craving. It is, however, doubtful whether these links can be oversimplified to that extent. It is also not clear whether craving can be understood as a psychological dimension or purely as the result of biological mechanisms. This uncertainty suggests, understandably, recourse to pharmaceutical strategies to influence the craving. At the same time, primary effects of substances on the dopaminergic system, secondary neuromodulation, and inadequate inhibitory facilities cannot be imagined without the psychological dimensions of the human experience, which are represented by way of reward expectation, life events, skills and self-consciousness. The question remains: are the findings from animal research transferable to humans? Can human addiction be projected biologically? Or is the neural basis of addiction mediated by reward expectations, cognitive attitudes, abilities and behavioural components, which are rooted in and formed by the social environment? Many such questions have been subjectively and controversially answered by researchers, therapists, psychologists, biologists and medical doctors on the basis of their individual experience, but there is as yet no consensus. The hope remains that an integrated conceptualisation concept of addiction, based on biological, social and psychological findings may lead to better understanding of addiction and the enhancement of the efficacy of existing therapies.