[unreadable] [unreadable] Tobacco smoking is a major public health problem that remains the largest preventable cause of morbidity and mortality in the United States. A greater understanding of mechanisms underlying the rewarding effects of smoking may improve our understanding of smoking behavior, and ultimately lead to better prevention and treatment strategies. There is evidence to suggest that nicotine is the primary active ingredient necessary for maintaining smoking behavior. However, non-nicotine factors also appear to play an important role in the rewarding effects of smoking. Preliminary evidence suggests that smokers' expectancies for the effects of smoking may influence the actual effects experienced after smoking (e.g., craving reduction, negative affect reduction), independent of nicotine. However, more research is needed in this area, and across a wider range of possible smoking outcomes. The primary aim of the proposed project is to continue development of a laboratory model to evaluate the relative contributions of nicotine and drug expectancies in the subjective and behavioral effects of smoking. The proposed project will utilize a 2 X 2 factorial balanced placebo design methodology, which crosses nicotine dose (nicotine vs. placebo) and dosage instructional set (told nicotine vs. told placebo), to evaluate the independent and interactive effects of nicotine and instructional set (a purported indirect measure of expectancies) on smoking outcomes. This study will also investigate gender and self-reported expectancies for nicotine as potential moderators of reactions to nicotine and instructional set manipulations. Outcomes assessed will include self-reported urge to smoke, withdrawal, mood, and a [unreadable] measure of behavioral performance. The results are likely to advance current knowledge of the relative [unreadable] contributions of nicotine and expectancies in determining the immediate effects of smoking. If expectancies are shown to be important proximal determinants of smoking outcomes and smoking behavior, further development of novel nicotine dependence prevention and treatment strategies such as expectancy challenges may be warranted. [unreadable] [unreadable]