Relative contributions of pharmacological, psychological and sensory-motor processes to the positive and negative reinforcing properties of tobacco smoking

Both the positive (e.g. incentive motivation) and negative (e.g. withdrawal relief) reinforcing properties of tobacco smoking are often attributed to a single factor: nicotine. However, there is surprisingly little unequivocal evidence that nicotine per se has either negative or positive reinforcing properties in the absence of other pharmacological (e.g. psychoactive effects of non-nicotine tobacco ingredients) and non-pharmacological factors (e.g. expectancy effects; sensory-motor aspects of tobacco use). In a recent series of studies, my research group has found that many of the negative reinforcing properties of smoking appear to be attributable to non-nicotine tobacco constituents and/or the sensory-motor aspects of smoking, while many of tobacco's positive reinforcing properties appear to be attributable at least in part to psychological factors such as expectancy. In the proposed program of research, I aim to continue to examine the positive and negative reinforcing effects of nicotine and various other pharmacological, sensory-motor and psychological smoking factors. It is expected that this work will 1) help identify the separate and common mechanisms involved in the positive and negative reinforcing effects of smoking and 2) delineate the relative contributions of nicotine, non-nicotine tobacco constituents, sensory-motor aspects of smoking, and psychological factors to each of these processes.