Conditioning history and the reinforcing effects of drugs: Comment on Alessi, Roll, Reilly, and Johanson (2002)

Drug reinforcement plays a central role in drug abuse. Drugs of abuse are unconditioned reinforcers whose functional effects are mediated through neuropharmacological mechanisms. The role of conditioning has received attention, but the focus has been on associations between environmental cues and unconditioned drug stimuli. Recent studies by C.-E. Johanson, A. Mattox, and C. R. Schuster (1995) and S. M. Alessi, J. M. Roll, M. P. Reilly, and C.-E. Johanson (2002) have demonstrated that drugs can also acquire functional control over human behavior through conditioning processes. Given the potent effects that conditioned reinforcers (e.g., money) can have on human behavior, studies by Johanson et al. and Alessi et al. should engender further examination of conditioning processes and drug reinforcement.