Animal models of behavior in drug addiction research: Research Model Validity

A variety of models have been created to understand the mechanisms of drug addiction. These have been separated by what types of behaviors are being observed such as Positive and Negative Reinforcing Effects, models for Intravenous Drug Self-Administration, models of relapse and drug-seeking behavior, reconsolidation of drug cue memories, compulsive and impulsive drug intake and neuroimaging. While these have been widely used and accepted, their validity within the field of research has been debated. Validity for these models is evaluated in three levels: their predictive validity (the predictive relationship between a manipulation in a model and the effect on the disorder that is modeled), face validity (how closely the model being used resembles the disorder being modeled) and construct validity (the theoretical rationale, the degree to which what is claimed to being measured is effectively measured). 

Image obtained from: http://www.med-associates.com/medlines/Summer2012/images/fig-1.gif An example of the self-administration paradigm. Image obtained from: http://www.med-associates.com/medlines/Summer2012/images/fig-1.gif An example of the self-administration paradigm.

Out of the models mentioned, the self-administration model has one of the highest face validities, considering that it is possible to get virtually any animal to self-administer the drug, but they can also self-administer other natural reinforcers such as food or sugar. Within the models of negative and positive reinforcing effects, paradigms which measure effects of withdrawal have fair face and predictive validities as they have shown to be predictive of withdrawal signs in humans. While the intravenous self-administration model is widely used, it has many issues concerning duration of exposure to new pharmacotherapeutic agents. It also has other issues that arise regarding behavioral responses in these paradigms. However, it is argued that some model the time and energy expended in order to obtain the drug.

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