Parsing the Addiction Phenomenon: Self-Administration Procedures Modeling Enhanced Motivation for Drug and Escalation of Drug Intake.

Investigators who study drug addiction are fortunate to have access to excellent animal models. Such models will be invaluable in the assessment of factors involved in the progression of drug addiction. The relevance of these findings, however, will depend on the general understanding of how each model is related to drug addiction. The present review focuses on several procedures that were designed to model the addiction process and questions whether these models are tapping into the same underlying process or whether each is addressing a unique feature. Furthermore, various factors (e.g., rate of drug onset, dose magnitude, early drug history, periods of abstinence) influencing the progression of these addiction-like changes in behavior are discussed.