The other learning process in substance abuse: comment on Alessi, Roll, Reilly, and Johanson (2002).

The results presented in the article by S. M. Alessi, J. M. Roll, M. P. Reilly, and C.-E. Johanson (2002) suggest that the reinforcing impact of diazepam can change as a function of the participant's experience with the drug. The data fit nicely with a long tradition in learning theory that has shown that the effects of reinforcers can depend crucially on what the organism has been able to learn about them. Often, that learning reflects an associative process like the one involved in Pavlovian conditioning. The hypothesis that preference for diazepam increased in the Alessi et al. study because the drug was associated with money would benefit from additional experiments that include control conditions isolating the role of the Pavlovian drug-money contingency.