Nicotine deprivation and trait impulsivity affect smokers' performance on cognitive tasks of inhibition and attention.

Self-control or impulsivity mechanisms have been identified in recent models of addiction, including nicotine addiction, as being at the core of the compulsive nature of addiction (Baker et al., 2004; Baumeister, 2003; Brady & Sinha, 2005; Everit & Robinson, 2005; Goldstein & Volkow, 2002; Jentsch & Taylor, 1999; Koob et al., 2004; Volkow, 2004). Historically conceptualized as a personality trait, self-control or impulsivity includes various facets such as impulse control, response inhibition, and behavioral regulation. When functioning properly, the exertion of self-control can serve to regulate immediate desires and delay gratification, with the goal of maximizing beneficial long-term outcomes (Hayes, Gifford, & Ruckstuhl, 1996). Along those lines, trait measures of self-control or impulsivity have been found to be associated with initiation (Wills & Stoolmiller, 2002), maintenance (Peluso et al., 1999; Piquero et al., 2002), and relapse to drug use (Doran, Spring, McChargue, Pergadia, & Richmond, 2004). For example, individuals who rated higher on trait impulsivity were likely to relapse to cigarette smoking faster than those individuals who rated lower (Doran et al., 2004). Although addicted individuals are more likely to be impulsive, self-control problems are often exacerbated in high challenge states (Kelley, Schiltz, & Landry, 2005; Sinha, 2005; Volkow & Li, 2005). One example of a high challenge state is nicotine deprivation. Nicotine deprivation has been shown to produce decrements in self-control as measured by delay discounting, which is a measure of how much an individual discounts a delayed reward as a function of the length of delay to the reward (Field, Santacangelo, Sumnall, Goudie, & Cole, 2006; Mitchell, 2004). Mitchell observed that 24 hours of nicotine deprivation resulted in increased discounting for cigarette-related choices. Field and colleagues (2006) observed that periods of at least 13 hours of nicotine deprivation resulted in impulsive choices for monetary and cigarette-related rewards. Together these two studies indicate that nicotine deprivation can increase impulsive decision making. Observations that the challenge state produced by nicotine deprivation may produce additional decrements in self-control are consistent with what is seen clinically, as withdrawal is often associated with relapse. Typically, relapse episodes happen soon after the start of the quit attempt, while the smoker is experiencing acute withdrawal symptoms (for a review, see Brown, LeJuez, Kahler, Strong, & Zvolensky, 2005). The high challenge state of nicotine deprivation has well-known detrimental effects on cognitive performance. Nicotine deprivation attributed to smoking abstinence has been associated with impaired performance on a wide variety of tasks, including those assessing attention (e.g., Bell, Taylor, Singleton, Henningfield, & Heishman, 1999; Harakas & Foulds, 2002; Myers, Taylor, Moolchan, & Heishman, 2008;), vigilance (e.g., Parrott, Garnham, Wesnes, & Pincock, 1996), working memory (e.g., Myers et al., 2008; Xu et al., 2006), cognitive processing and response accuracy (e.g., Snyder, Davis, & Henningfield, 1989) and overall cognitive performance (e.g., al’Absi, Amunrud, & Wittmers, 2002). Although the effects of nicotine deprivation on cognition are well characterized, the relationship between deprivation-induced cognitive impairment and trait impulsivity is largely unknown. As nicotine deprivation increases, individuals with varying levels of trait impulsivity could be differentially affected. Moreover, various facets of impulsivity could have different relationships with nicotine deprivation-induced cognitive deficits. These cognitive deficits, in turn, could have a role as a motivating influence in smoking relapse and could in part explain why more impulsive individuals relapse faster than those who are less impulsive (e.g., Doran et al., 2004). The purpose of the present investigation was to examine the influences of increasing levels of nicotine deprivation and of trait impulsivity on cognitive processing in daily smokers. To examine these effects, trait impulsivity was measured at study intake with the Barratt Impulsiveness Scale (BSI) (Patton, Stanford, & Barratt, 1995), a well known measure of trait impulsivity. The study used a within-subject design in daily smokers who were nondeprived, or nicotine deprived for 5 or 17 hours. The 5-hr nicotine deprivation condition represented acute deprivation, targeting increases in tobacco craving (Drobes & Tiffany, 1997). The 17-hr deprivation condition represented a period of more prolonged deprivation, targeting increases in craving, as well as additional tobacco withdrawal symptoms (Hatsukami, Hughes, Pickens, & Svikis, 1984). Main effects and interactions of nicotine deprivation and trait impulsivity were assessed on measures of cognitive performance, which included the Conners’ Continuous Performance Task (CPT-II; Conners, 2000) and the Cued Go/No-Go Task (CGNG; Marczinski & Fillmore, 2003). Cognitive testing occurred within each level of nicotine deprivation. The CPT-II task is designed to assess sustained attention, concentration, response inhibition, and impulsivity. Nicotine deprivation has been found to produce performance decrements in CPT-II outcomes, which were ameliorated with smoking resumption (e.g., Sacco et al., 2005). The CGNG task is sensitive to drug effects and assesses behavioral activation and inhibition. Prior research has indicated that overnight nicotine deprivation resulted in impaired performance on the task (e.g., McClernon et al., 2008). Given past research indicating the general finding that nicotine deprivation impairs cognitive processing (e.g., Bell et al., 1999; Synder et al., 1989), nicotine deprivation-induced changes in task performance were predicted. Associations between trait impulsivity and performance at each level of nicotine deprivation were examined using mixed model regression analyses. We explored the degree to which nicotine deprivation-related changes in cognitive processing were associated with trait impulsivity. More impulsive individuals might experience differential changes after nicotine deprivation. An understanding of the relationship between trait impulsivity and changes in cognitive performance after nicotine deprivation could in part explain differences observed in rates of smoking cessation among individuals of varying levels of impulsivity.