Integrated theories of drug abuse
There are many means of studying the aetiology of drug abuse but no clearcut explanations as to why some individuals who experiment with drugs go on to abuse them and others do not. Drug abuse appears to be a multifactorial process. To provide a more comprehensive understanding of the development of drug use and abuse, researchers combine single-factor type models (presented in Chapters 5 and 6) through use of various decision rules to create integrated models. That is, integrated models (or integrated theories, the terms ‘models’ and ‘theories’ are used interchangeably here) are defined as models that utilize two or more single-factors in a poly-factor model combined, based on some a priori rules of combination. Several different integrated substantive models have been developed. One simple means of integration has been simply to add single concepts or predictors together. This approach has been referred to as the ‘risk and protective factors’ of drug abuse. A second approach has been carefully to delineate non-overlapping factors, and then combine factors together. This approach has been used in different biopsychosocial models. A third approach has been to take a more deductive, theoretical scheme, as has been the case with functional meanings models, the ‘problem behaviour model’ or triadic influence theory. Other means of combining single-factor type models include stage modelling (predictors of onset, experimentation, regular use, abuse and dependence) and integrating variables at different ‘distances’ from drug use behaviour (distal/environmental-proximal/intrapersonal). Finally, one might go back to the drawing board and consider a simple, hedonic treadmill model as the root of drug abuse. A return to a simple model might help rectify the myriad of idiographic peculiarities in the paths leading to drug abuse. A summary of these approaches is depicted in Table 7.1.