the development of negative emotions. One question that we were unable to address is the temporal order of smoking behavior and expectancies. It is possible that the relation of AS to smoking expectancies exists prior to smoking initiation and may reflect expectations born out of factors other than direct smoking experience (e.g., modeling by peers and experiences regarding the negative reinforcing effects of other behaviors). Future longitudinal studies will be able to better address this question. Another limitation is that the study’s correlational nature leaves open the possibility that an unknown extraneous variable is responsible for the described interrelations. However, this concern is somewhat offset by statistical control in adjusted analyses. Finally, exclusion criteria included non-nicotine substance dependence, current mood disorder or psychotic symptoms, use of non-cigarette forms of tobacco, and planning to quit smoking. Hence, implications of these findings to the wider population of smokers who may experience psychiatric comorbidities or may be interested in quitting smoking should be drawn with this caveat in mind. For example, excluding individuals with non-nicotine substance dependence may have restricted the range of negative urgency, thereby weakening relations with negative urgency and potentially obscuring significant mediational pathways beyond those found in the current
