Chunk #18 — 1. Definitions and conceptual framework for compulsivity in addiction — 1.3. Animal models of compulsivity in addiction as defined by increased drug taking: Escalation in drug self-administration with prolonged access
A progressive increase in the frequency and intensity of drug use is one of the major behavioral phenomena characterizing the development of addiction and has face validity with the criteria of the Diagnostic and Statistical Manual of Mental Disorders: “The substance is often taken in larger amounts and over a longer period than was intended” (American Psychological Association, 1994). A framework with which to model the transition from drug use to drug addiction can be found in recent animal models of prolonged access to intravenous cocaine self-administration. Historically, animal models of cocaine self-administration involved the establishment of stable behavior from day to day to allow the reliable interpretation of data provided by within-subject designs aimed at exploring the neuropharmacological and neurobiological bases of the reinforcing effects of acute cocaine. Up until 1998, after acquisition of self-administration, rats typically were allowed access to cocaine for 3 h or less per day to establish highly stable levels of intake and patterns of responding between daily sessions. This was a useful paradigm for exploring the neurobiological substrates for the acute reinforcing effects of drugs of abuse.
