Conditioned effects of environmental stimuli paired with smoked cocaine inhumans

Rationale: Clinical data suggest that stimuli paired with cocaine use acqui re emergent stimulus effects. such as the ability to elicit cocaine craving . Objectives: The purpose of this study was to determine the conditioned ef fects of neutral stimuli paired with cocaine smoking. Methods: Eight experi enced adult cocaine smokers participated in 22 experimental sessions while residing on a Clinical Research Center. One set of cues (CS-) was paired wi th placebo smoked cocaine and one set of cues (CS+) was paired with 25 mg s moked cocaine. Results: After 18 training trials, the effects of cocaine on heart rate and ratings of "anxious" were greater, and skin temperature and ratings of "tired'' were smaller when compared to the effects of cocaine a fter the first training trial. When instructed to select a cue to experienc e after training, seven of eight participants selected the CS+. while only three of the participants selected the CS+ prior to training, i.e., the CS- e functioned as a conditioned reinforcer. Presentation of the CS+ alone wit hout cocaine during extinction trials increased HR, SP, and ratings of "anx ious" "tired", and "I want cocaine" and decreased skin temperature. These c hanges elicited by presentation of the CS+ decreased over the course of the extinction sessions. Conclusions: The present results indicate that classi cal conditioning is one mechanism by which stimuli paired with cocaine acqu ire emergent stimulus effects.