Cam: An animal learning model of excessive and compulsive implementassisted drug-taking in humans

Animal learning studies reveal that locating the reward cue (discriminative stimulus positively correlated with the presentation of positive reinforcement) at the site of the response manipulandum (object contacted in performing the instrumental response), an arrangement referred to as CAM (cue and manipulandum), induces excessive instrumental responding. CAM induces excessive responding even when responding is negatively related to reinforcement and serves only to delay or cancel reinforcement, revealing that excessive responding induced by CAM is unrestrainable and compulsive. In addition, the response form induced by CAM resembles patterns of consummatory behaviors. Thus, animal learning studies reveal that CAM induces excessive and compulsive appetitive-consummatory responding that is triggered by objects predictive of rewarding substances. The CAM model defines conditions under which the drug-taking implement the response manipulandum at which instrumental drug-taking behavior is directed) will contribute to the development of excessive and compulsive drug-taking in humans. Implementassisted drug-taking procedures in humans provide for CAM whenever the drug-taking implement is positively correlated with the drugʹs reinforcing effects. This correlation is highest when the drug-taking implement is employed only to consume the drug and the drug is consumed in no other fashion. Evidence relating drug-taking implements to drug abuse is reviewed and implications for prevention and therapy are considered.