COGNITIVE PERFORMANCE EFFECTS OF SUBCUTANEOUS NICOTINE IN SMOKERS ANDNEVER-SMOKERS

In a double-blind placebo-controlled crossover study the effects of tw o doses of subcutaneous nicotine and saline were compared on a range o f performance measures in 18 abstaining smokers and 18 never-smokers. Each subject received two injections (40 min apart) of saline, 0.3 mg nicotine, or 0.6 mg nicotine in a balanced order over three sessions. Performance was assessed before and after the injections on nine tests [news recall, Sternberg memory task, finger tapping, logical reasonin g, rapid visual information processing (RVIP), long-term word recognit ion, digit recall, Stroop test, and critical flicker fusion threshold] . In the abstinent smokers, nicotine produced significantly faster cor rect responses on the logical reasoning test, more target hits, faster reaction times and improved sensitivity on the RVIP task, and more co rrect responses on word recognition. In never-smokers, nicotine produc ed faster reaction times on the RVIP and digit-recall tasks, although in the latter case this was at the expense of fewer correct responses. There were no significant differences between the two groups' respons es to nicotine but smokers performed worse than never-smokers prior to injections, even controlling for background characteristics. These re sults are consistent with other recent research suggesting a primary e ffect of nicotine in enhancing cognitive performance.