The relationship between impulsivity, risk-taking propensity and nicotine dependence among older adolescent smokers.

Impulsivity and risk-taking propensity are neurobehavioral traits that reliably distinguish between smoking and non-smoking adults. However, how these traits relate to smoking quantity and nicotine dependence among older adolescent smokers is unclear. The current study examined impulsivity and risk-taking propensity in relation to smoking behavior and nicotine dependence among current older adolescent smokers (age 16-20 years; N=107). Participants completed the Barratt Impulsiveness Scale-11 (BIS-11), the Balloon Analogue Risk Task (BART), and self-report measures of smoking behavior and nicotine dependence. Results indicated a significant positive relationship between nicotine dependence and the Attention subscale (ß=.20, t=2.07, p<.05) and the Non-planning subscale (ß=.19, t=1.92, p<.06) of the BIS-11. Contrary to expectation, the results also indicated a significant negative relationship between performance on the BART and nicotine dependence (ß=-.19, t=-2.18, p<.05), such that greater risk-taking propensity was associated with less dependence. These data suggest that impulsivity and risk-taking propensity are related to older adolescent smoking but are separable traits with distinguishable associations with nicotine dependence among adolescents. These findings support the notion that impulsivity is related to heightened nicotine dependence, but suggest that the relationship between risk-taking propensity and nicotine dependence is more ambiguous and warrants further investigation.

Rate dependent effects of acute nicotine on risk taking in young adults are not related to ADHD diagnosis.

Beneficial effects of nicotine on cognition and behavioral control are hypothesized to relate to the high rates of cigarette smoking in Attention-Deficit/Hyperactivity Disorder (ADHD). Given that ADHD is associated with both impulsivity and elevated risk taking, we hypothesized that nicotine modulates risk taking, as it does impulsivity. 26 non-smoking young adults (15 controls with normal impulsivity and 11 ADHD with high impulsivity) received 7 mg transdermal nicotine, 20mg oral mecamylamine, and placebo on separate days, followed by the Balloon Analog Risk Task (BART). Statistical analyses found no group differences in baseline risk taking. Reexamination of the data using a median split on baseline risk taking, to create high (HRT) and low (LRT) risk taking groups, revealed significant effects of nicotinic drugs that differed by group. Nicotine reduced risk taking in HRT and mecamylamine increased risk taking in LRT. This finding supports the hypothesis that nicotinic receptor function modulates risk taking broadly, beyond those with ADHD, and is consistent with rate dependent cholinergic modulation of other cognitive functions. Further, the results demonstrate that high impulsivity is separable from high risk taking in young adults with ADHD, supporting the utility of these differential behavioral phenotypes for neurobiological studies.

Predictors of cessation pharmacotherapy use among black and non-Hispanic white smokers.

INTRODUCTION: Use of pharmacotherapy for smoking cessation improves quit rates, but these treatments are underutilized, particularly among Black smokers. Attitudes toward pharmacotherapy may differ between racial/ethnic minorities and Caucasian smokers. It was hypothesized that Black and non-Hispanic White smokers would differ in their attitudes toward pharmacotherapy and that the association between attitudes toward and actual use of pharmacotherapy would differ by race. METHODS: The study consisted of a single, cross-sectional telephone-based survey of current smokers (N = 697), which examined the relationship between race, attitudes toward pharmacotherapy, and pharmacotherapy usage in a representative bi-racial sample (39% Black). RESULTS: Black smokers were significantly less likely to report ever use of pharmacotherapy (23%) than Caucasians (39%; odds ratio [OR] = 0.46; 95% CI: 0.33-0.66). Compared with Caucasians, Blacks had significantly less favorable attitudes toward pharmacotherapy, including disbelief about efficacy (p = .03), addiction concerns (p = .03), harmfulness of pharmacotherapy (p = .008), and need for treatment of any kind to quit smoking (p = .004). In a multiple logistic regression, racial group (Caucasian is referent: OR = 0.55, p = .003), addiction concerns (OR = 0.80, p < .01), and need for treatment of any kind to quit smoking (OR = 1.52, p < .001) were predictive of pharmacotherapy use. CONCLUSIONS: These findings replicate and build upon previous research demonstrating underutilization of pharmacotherapy and enduring misconceptions about pharmacotherapy, particularly among Black smokers. Regardless of racial group, misconceptions about pharmacotherapy are related to lower rates of use. Efforts to improve understanding about the efficacy and safety of these products are needed to boost utilization and impact cessation rates.

Effects of acute ultra-low dose mecamylamine on cognition in adult attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE: Nicotinic cholinergic stimulation has known beneficial effects in attention-deficit/hyperactivity disorder (ADHD). Mecamylamine is a non-competitive nicotinic antagonist which is reported in several animal studies to have paradoxical positive effects on cognition at ultra-low doses. Comparable studies in humans have not been conducted. The aim of this study was to determine the effects of acute ultra-low doses of mecamylamine on cognition in adult ADHD. METHODS: Fifteen (6 female) non-smokers with ADHD completed this acute, within subjects, double blind study of 0.2, 0.5, 1.0 mg of oral mecamylamine and placebo. Behavioral inhibition, recognition memory, and delay aversion were assessed at each dose. RESULTS: The 0.5 mg dose of mecamylamine significantly improved recognition memory and reduced tolerance for delay. Mecamylamine increased participant rated irritability and investigator rated restlessness. There were no effects on vital signs or physical side effects. CONCLUSION: This is the first study to find measurable effects of ultra-low doses of mecamylamine in humans. Mecamylamine did not improve core ADHD cognitive symptoms, but significantly improved recognition memory. These effects may represent mixed receptor activity (activation and blockade) at the doses tested. The finding of beneficial effects on memory processes has important clinical implications and further exploration of this effect is warranted.

Compensatory neural activity distinguishes different patterns of normal cognitive aging.

Most cognitive neuroscientific research exploring the nature of age-associated compensatory mechanisms has compared old adults (high vs. average performers) to young adults (not split by performance), leaving ambiguous whether findings are truly age-related or reflect differences between high and average performers throughout the life span. Here, we examined differences in neural activity (as measured by ERPs) that were generated by high vs. average performing old, middle-age, and young adults while processing novel and target events to investigate the following three questions: (1) Are differences between cognitively high and average performing subjects in the allocation of processing resources (as indexed by P3 amplitude) specific to old subjects, or found throughout the adult life span? (2) Are differences between cognitively high and average performing subjects in speed of processing (as indexed by target P3 latency) of similar magnitude throughout the adult life span? (3) Where along the information processing stream does the compensatory neural activity attributed to cognitively high performing old subjects begin to take place? Our results suggest that high performing old adults successfully manage the task by a compensatory neural mechanism associated with the modulation of controlled processing and the allocation of more resources, whereas high performing younger subjects execute the task more efficiently with fewer resources. Differences between cognitively high and average performers in processing speed increase with age. Middle-age seems to be a critical stage in which substantial differences in neural activity between high and average performers emerge. These findings provide strong evidence for different patterns of age-related changes in the processing of salient environmental stimuli, with cognitive status serving as a key mediating variable.

Increased responsiveness to novelty is associated with successful cognitive aging.

The animal literature suggests that exposure to more complex, novel environments promotes neurogenesis and cognitive performance in older animals. Studies in humans indicate that participation in intellectually stimulating activities may serve as a buffer against mental decline and help to sustain cognitive abilities. Here, we show that across old adults, increased responsiveness to novel events (as measured by viewing duration and the size of the P3 event-related potential) is strongly linked to better performance on neuropsychological tests, especially those involving attention/executive functions. Cognitively high performing old adults generate a larger P3 response to visual stimuli than cognitively average performing adults. These results suggest that cognitively high performing adults successfully manage the task by appropriating more resources and that the increased size of their P3 component represents a beneficial compensatory mechanism rather than less efficient processing.

Age-related differences in attention to novelty among cognitively high performing adults.

Age-related differences in attention to novel events were studied in well-matched, cognitively high performing old, middle-aged and young subjects. Event-related potentials were recorded during a visual novelty oddball task in which subjects controlled viewing durations that served as a behavioral measure of attentional allocation. All age groups had a larger P3 amplitude and longer viewing duration to novel than to standard stimuli, with no age-related differences in the magnitude of these effects, indicating old individuals were as engaged by the processing of novelty as younger adults. Old subjects had a larger, more anteriorly distributed P3 component to novels and standards. The increased P3 amplitude differs from prior reports of a diminished P3 response with processes, including aging, that have a potentially deleterious impact on the brain. We hypothesise that cognitively high performing old individuals successfully manage the task by relying on additional neural resources and perhaps more effortful frontal activity than their younger counterparts.

Age-related differences in novelty and target processing among cognitively high performing adults.

Previous research on age-related changes in ERP components in response to novel and target stimuli has not carefully controlled for differences in level of cognitive status between age groups, which may have contributed to the common findings of increased P3 latency, decreased P3 amplitude, and altered P3 scalp distribution. Here, cognitively high-performing (top third based on published norms) old, middle-aged, and young adults matched for IQ, education, and gender participated in a novelty oddball paradigm. There were no age-associated differences in P3 latency. Older adults had a larger, more anteriorly distributed P3 amplitude to all stimulus types, even repetitive standards, suggesting they may rely on increased resources and effortful frontal activity to successfully process any kind of visual stimulus. However, after controlling for this non-specific age-related processing difference, the amplitude and scalp distribution of the P3 component to novel and target stimuli were comparable across age groups, indicating that for cognitively high functioning elders there may be no age-related differences specific to the processing of novel and target events as indexed by the P3 component.