Addiction is characterized as a chronic debilitating disease. One devastating feature of addiction is the susceptibility of relapse (40-60%) after stretches of abstinence. One theory that may account for relapse suggests that drug cues (e.g., paraphernalia) may increase stress hormones, and this may prompt relapse. Repeatedly pairing a neutral cue with a reward is commonly utilized to measure what subjects learn about a cue that is predictive of reward. Research has shown that animals that attend to a cue more than to the reward (sign trackers) may be more vulnerable to drug addiction. Additionally, research has shown that sign tracking is associated with an increase in corticosterone, a primary stress hormone. PT150 is a novel glucocorticoid receptor antagonist that moderates the release of corticosterone. In the current experiment, it was hypothesized that subjects given repeated administration of PT150 would reduce sign tracking compared to subjects given placebo. Time spent (in seconds) near a cue that predicts reward (conditional stimulus) served as a measure of sign tracking, and PT150 or placebo was administered following sign tracking. An independent-samples t test revealed that subjects that received PT150 had reduced time spent near the conditioned stimulus compared to controls. Given the devastating effects of drug addiction, identification of a potential pharmacological intervention in the reduction of relapse would be of great value. Therefore, future research is needed to validate the use of PT150 in reducing behaviors associated with drug addiction. (PsycINFO Database Record