Participants in each group will complete the laboratory-based, delayed smoking procedure in a designated, negative pressure room in Bldg. 36 of the West Haven VA just after assessing pain sensitivity with the cPT. This sequence allows the cPT to assess pain sensitivity, a potential biomarker of relapse behavior, and to also be used as a mild stressor prior to participation in the smoking relapse model. Participants will be instructed to abstain from smoking after 10 pm the night before Test Sessions. Abstinence will be confirmed the morning of the session by measuring a breath CO level of < 8 ppm.