The participants were medically healthy and did not have current active medical problems (including hypertension) and were not on any current prescription medications. Potential participants were excluded if they were dependent on alcohol or any drugs other than nicotine, as determined by the Structured Clinical Interview for DSM-IV (24) and verified by urine drug screening. Written informed consent was obtained from each participant prior to study participation. The IV nicotine experimental sessions were conducted in the Biostudies Unit located at the West Haven campus of the VA Connecticut Healthcare System. The participants were compensated for their participation. This research protocol was approved by the Yale and VA Connecticut Healthcare System Human Subjects Subcommittees.
