Rationale and objective Empirical studies indicate that nicotine enhances some aspects of attention and cognition, suggesting a role in the maintenance of tobacco dependence. The purpose of this review was to update the literature since our previous review (Heishman et al. Exp Clin Psychopharmacol 2:345–395, 1994) and to determine which aspects of human performance were most sensitive to the effects of nicotine and smoking. Methods We conducted a meta-analysis on the outcome measures of 41 double-blind, placebo-controlled laboratory studies published from 1994 to 2008. In all studies, nicotine was administered, and performance was assessed in healthy adult nonsmokers or smokers who were not tobacco-deprived or minimally deprived (≤2 h). Results There were sufficient effect size data to conduct meta-analyses on nine performance domains, including motor abilities, alerting and orienting attention, and episodic and working memory. We found significant positive effects of nicotine or smoking on six domains: fine motor, alerting attention-accuracy and response time (RT), orienting attention-RT, short-term episodic memory-accuracy, and working memory-RT (effect size range=0.16 to 0.44). Conclusions The significant effects of nicotine on motor abilities, attention, and memory likely represent true performance enhancement because they are not confounded by withdrawal relief. The beneficial cognitive effects of nicotine have implications for initiation of smoking and maintenance of tobacco dependence.

We examined an approach aimed at training consciously-controlled recollection, introduced by Jennings and Jacoby (2003) , for its ability to replicate and generalize. A continuous recognition task, requiring recollection to identify the occurrence of repeated items over gradually increasing lag intervals (number of intervening items between the first and second presentation of a repeated word), was given to a group of older adults twice a week for three weeks. Pre-and-post training performance was assessed on multiple measures and compared with a recognition practice and no contact control group. Recollection training proved successful; accurate identification of repeated items increased across a lag interval of 2 to 18 intervening items. Post-training gains following recollection training were found on n-back, self-ordered pointing, source discrimination and digit symbol substitution, but not with reading span or the CVLT-II. No changes were identified in the other groups. Gains from recollection training seem to transfer successfully in older adults.

Smoking-related cancer and other disease account for more than 400,000 U.S. deaths annually. Smoking cessation reduces smoking-related disease rates, but relapse rates are high. Thus, interest in reducing the harm of continued smoking is growing. Potential reduced exposure products (PREPs) are marketed to reduce smokers' exposure to smoke toxicants such as carbon monoxide (CO) and carcinogens and may be harm reduction tools. New PREPs are proliferating, but past experience with "low-yield" cigarettes that failed to reduce smokers' toxicant exposure suggests that comprehensive evaluation is necessary to predict if these new products are likely to alter the harm caused by smoking. The purpose of the study was to develop clinical laboratory methods for PREP evaluation. Smokers (N = 35) completed four, 5-day conditions that differed by product used: Advance, Eclipse, own brand cigarettes, or no cigarettes. Carcinogen (as assessed by one nitrosamine and one polycyclic aromatic hydrocarbon biomarker) and nicotine exposure were assessed via thrice-weekly urine sampling. Withdrawal symptoms were measured daily, and smoking behavior was assessed on the first and last day of each condition. Relative to own brand, Advance reduced exposure to the nitrosamine NNK and CO, and Eclipse reduced exposure to nicotine and the nitrosamine NNK, increased exposure to CO, and resulted in larger, longer, and more frequent puffs. No smoking reduced exposure to the nitrosamine NNK, CO, and nicotine, whereas withdrawal was elevated (all p values <.05). Clinical laboratory evaluation of PREPs for smokers is valuable for measuring users' smoke toxicant exposure, withdrawal, and smoking behavior and should be incorporated into a comprehensive PREP evaluation strategy.

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The subjective and physiological effects of nicotine in nicotine-naive individuals are consistent across studies, though the cognitive effects are variable: Positive, negative, or no effects have been reported. Assessing specific cognitive processes (e.g., alerting, orienting, executive function, and phonological and visuospatial working memory) may help reduce this variability. This within-subject study (N = 20) was designed to assess the effect of nicotine gum (0, 2, or 4 mg) on subjective, physiological, and cognitive measures. Dose-dependent increases in dysphoria and heart rate were observed, though nicotine did not influence any aspect of attention or working memory. Future studies should take into account the difference in effect sizes for cognitive versus physiological/subjective measures and maximize power (e.g., increase sample size) accordingly.

Benzodiazepines and alcohol are widely used psychoactive substances that have performance-impairing effects. Research suggests that the impairment profiles for benzodiazepines and alcohol differ, though few cognitive psychopharmacological studies have directly compared these drugs. This double-blind, double-dummy, placebo-controlled, repeated measures study directly compared the acute dose effects of triazolam (0.125 mg, 0.25 mg/70 kg) and alcohol (0.40 g, 0.80 g/kg) in 20 social drinkers. At doses that produced comparable psychomotor impairment, triazolam was more likely to impair several objective measures of cognitive performance (e.g., episodic memory, divided attention) and to slow performance across several measures. However, only alcohol impaired accuracy on the digit symbol substitution and semantic memory tasks. In addition to objective measures, both drugs impaired awareness of performance impairments (i.e., metacognition) such that participants over-estimated impairment, and the magnitude of this effect was generally larger for alcohol. Only triazolam impaired other measures of metacognition (e.g., error detection on a choice reaction time task). Future research might examine the clinical implications of the performance impairments reported here given the widespread use of benzodiazepines and alcohol.

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Smoking prevalence in the United States is lower among older adults (≥ 65 years of age; 8.3%) compared with younger adults (≤ 64 years; 22.2%); however, older adults are half as likely to try to quit as smokers aged 18 to 24 years (25.3% vs 53.1%) 1 . Smoking rates between 1965 and 1994 declined less for individuals 65 or older (5.9% reduction) than for younger adults (≤ 64 years; 18.4% reduction) 2 . Regardless of age, quitting smoking can increase life expectancy and improve health and quality of life 3 . Accordingly, the Clinical Practice Guideline for the Treatment of Tobacco Use and Dependence highlights older smokers as a subpopulation for which treatments might require tailoring because of unique age-related characteristics 4 . Clinicians should consider that older smokers will be an increasing proportion of the patient population and that these smokers might require modification of treatment for smoking cessation.