Effects of training dose on the relationship between discriminative-stimulus and self-reported drug effects of d-amphetamine in humans

The aim of the present experiment was to examine the relationship between t he discriminative stimulus and self-reported effects of drugs in humans. To accomplish this aim, nine healthy adult volunteers (four females, five mal es) were trained to discriminate between placebo and 10 mg d-amphetamine (l ow-dose group) or 20 mg d-amphetamine (high-dose group). after acquiring th e placebo-amphetamine discrimination, a range of doses of d-amphetamine (1. 25-20 mg) was tested to determine if they shared discriminative stimulus ef fects with the training dose. Participants in the low-dose group exhibited a significant leftward shift in the dose-response function for discriminati on performance, which is concordant with previous preclinical and human dru g discrimination studies that assessed the effects of training dose. Consis tent with the drug discrimination findings, participants in the low-dose gr oup exhibited a significant leftward shift in the dose-response function fo r several self-reported drug effects (e.g., Like the Drug and Stimulated). However, several other self-reported drug effect items were not significant ly influenced by training condition (e.g., Anxious/Nervous and Bad Effects) . These results suggest that the discriminative-stimulus and self-reported drug effects of d-amphetamine overlap, but are not isomorphic. Furthermore, these results illustrate that behavioral history significantly influences subsequent drug effects in humans. (C) 1999 Elsevier Science Inc.