Differences in Delay, but not Probability Discounting, in Current Smokers, E-cigarette Users, and Never Smokers

A systematic review and meta-analysis of the relationship between heavy smoking and probability discounting

BACKGROUND AND OBJECTIVES

Probability discounting (PD), which refers to the process of adjusting the value of future probabilities when making decisions, is a method of measuring impulsive decision-making; however, the relationship between PD and nicotine remains unclear. The current study aimed at investigating the significance of PD in individuals who smoke.

METHODS

According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched the PubMed, Embase, PsycINFO, and Web of Science databases for articles comparing individuals who smoke and their tobacco-naïve controls using PD task as outcome measure from inception to May 2023. The main outcome was an overall difference in PD function, while subgroup analysis and meta-regression were conducted to examine the analysis methods and the moderators of PD.

RESULTS

Fourteen studies in total involving 384 individuals who smoke and 493 controls (mean age = 24.32 years, range = 15.1-38.05 years) were analyzed. The effect of smoking on PD was significant (g = 0.51, p = .02). The discounting parameter from the equation, compared to the area under the curve, was more sensitive to estimating PD function (p = .01). Regression analysis showed positive correlations of PD with female percentage, age, and the number of probability options (all p < .04), but not with the number of choices at each probability and maximum reward magnitude (all p > .07). There was no significant publication bias across the eligible studies (p = .09).

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Our findings, which are the first to demonstrate a smaller PD (i.e., prone to risk-taking) in individuals who smoke, shed light on the appropriate analysis method, gender effect, age, and probability options on the PD function.

Early life adversity and substance use: The mediating role of mood and the moderating role of impulsivity

INTRODUCTION

Early life adversity (ELA) is a risk factor for substance use and misuse, and multiple factors mediate and moderate this association. We examined whether moods mediate the relationships between ELA and nicotine use, cannabis use, and co-use, and whether these mediation effects varied as a function of delay discounting.

METHODS

A total of 2555 adults completed a delay discounting task and responded to questions related to demographics, ELA, mood, and substance use. Data were analyzed using Pearson correlations and moderated mediation using Hayes' PROCESS macro (V3.4, Model 15).

RESULTS

ELA was positively associated with cannabis use, nicotine use, co-use of both substances, depressed and stressed moods, and it was negatively associated with positive mood. While cannabis use was associated negatively with stressed and depressed moods and positively with positive mood, nicotine use was associated negatively with positive mood. Moderated mediation analyses indicated that positive mood mediated the relationship between ELA and cannabis use for those with average and above average delay discounting. Positive mood also mediated the relationship between ELA and co-use among those with above average delay discounting.

CONCLUSION

The results suggest that ELA's associations with cannabis use and cannabis-nicotine co-use may be partially attributable to ELA's effects on positive mood among those who are predisposed to moderately to highly impulsive decision making.

Effects of short-term nicotine deprivation on delay discounting among young, experienced, exclusive ENDS users: An initial study

Delay discounting describes how rapidly delayed rewards lose value as a function of delay and serves as one measure of impulsive decision-making. Nicotine deprivation among combustible cigarette smokers can increase delay discounting. We aimed to explore changes in discounting following nicotine deprivation among electronic nicotine delivery systems (ENDS) users. Thirty young adults (aged 18-24 years) that exclusively used ENDS participated in two laboratory sessions: one with vaping as usual and another after 16 hr of nicotine deprivation (biochemically assessed). At each session, participants completed a craving measure and three hypothetical delay discounting tasks presenting choices between small, immediate rewards and large, delayed ones (money-money; e-liquid-e-liquid; e-liquid-money). Craving for ENDS significantly increased during short-term nicotine deprivation relative to normal vaping. Delay discounting rates in the e-liquid now versus money later task increased (indicating a shift in preference for smaller, immediate rewards) following short-term nicotine deprivation relative to vaping as usual, but no changes were observed in the other two discounting tasks. Short-term nicotine deprivation increased the preference for smaller amounts of e-liquid delivered immediately over larger, monetary awards available after a delay in this first study of its kind. As similar preference shifts for drug now versus money later have been shown to be indicative of increased desire to use drug as well as relapse risk, the findings support the utility of the current model as a platform to explore interventions that can mitigate these preference shifts. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Increased Risky Choice and Reduced CHRNB2 Expression in Adult Male Rats Exposed to Nicotine Vapor

While the cognitive enhancing effects of nicotine use have been well documented, it has also been shown to impair decision making. The goal of this study was to determine if exposure to nicotine vapor increases risky decision making. The study also aims to investigate possible long-term effects of nicotine vapor exposure on the expression of genes coding for cholinergic and dopaminergic receptors in brain. Thirty-two adult male Sprague Dawley rats were exposed to 24 mg/mL nicotine vapor or vehicle control, immediately followed by testing in the probability discounting task for 10 consecutive days. Fifty-four days after the 10-day vapor exposure, animals were sacrificed and expression of genes coding for the α4 and β2 cholinergic receptor subunits, and dopamine D1 and D2 receptors, were analyzed using RT-PCR. Exposure to nicotine vapor caused an immediate and transient increase in risky choice. Analyses of gene expression identified significant reductions in CHRNB2 and DRD1 in the nucleus accumbens core and CHRNB2 and DRD2 in the medial prefrontal cortex of rats previously exposed to nicotine vapor, relative to vehicle controls. Results provide data on the negative cognitive effects of nicotine vapor exposure and identify cholinergic and dopaminergic mechanisms that may affected with repeated use.

Monetary Reward Discounting, Inhibitory Control, and Trait Impulsivity in Young Adults With Internet Gaming Disorder and Nicotine Dependence

Internet Gaming Disorder (IGD) has been considered a potential behavioral or non-substance addiction that requires further investigation. Recognition of the commonalities between IGD and Substance Use disorders (SUD) would be of great help to better understand the basic mechanisms of addictive behaviors and excessive Internet gaming. However, little research has targeted a straightforward contrast between IGD and SUD on neuropsychological aspects. The present study thus aimed to explore the associations of reward processing and inhibitory control with IGD and nicotine dependence (ND) in young adults. Fifty-eight IGD and 53 ND individuals, as well as 57 age- and gender-matched healthy controls, were assessed with a series of measurements including the Delay-discounting Test (DDT), Probability Discounting Test (PDT), the Stroop Color-Word Task, a revised Go/No Go Task, and the Barratt Impulsiveness Scale (BIS-11). Multivariate analysis of variance (mANOVA) models revealed that both IGD and ND groups scored higher than healthy controls on the BIS-11 attentional, motor, and non-planning impulsiveness (Cohen's d = 0.41-1.75). Higher degrees of delay discounting on the DDT were also found in IGD and ND groups compared to healthy controls (Cohen's d = 0.53-0.69). Although IGD group did not differ from healthy controls on the PDT, ND group had a lower degree of probability discounting than healthy controls (Cohen's d = 0.55), suggesting a reduction in risk aversion. Furthermore, ND subjects showed a lower correct accuracy in the incongruent trials of the Stroop task than healthy controls (Cohen's d = 0.61). On the Go/No Go task, both IGD and ND groups had a lower correct accuracy in the No-Go trials than healthy controls (Cohen's d = 1.35-1.50), indicating compromised response inhibition. These findings suggested that IGD was linked to both anomalous reward discounting and dysfunctional inhibitory control, which was comparable with one typical SUD category (i.e., ND). This study might promote a better understanding of the pathogenesis of IGD as a potential addictive disorder similar to SUD.

Delay and probability discounting in cocaine use disorder: Comprehensive examination of money, cocaine, and health outcomes using gains and losses at multiple magnitudes

Understanding factors associated with cocaine use disorder is important given its public health impact. One factor is delay discounting (devaluation of future consequences). Cocaine users have shown greater delay discounting of money rewards than non-cocaine users. But underexamined are factors known to affect discounting, such as the sign (reward vs. loss), magnitude (e.g., $10 vs. $1,000), and commodity (e.g., money vs. health) of the consequence. Also underexamined is probability discounting (devaluation of uncertain consequences). We conducted a comprehensive group-comparison study of discounting processes by comparing sign, magnitude, and commodity effects between demographically matched cocaine users (n = 23) and never users (n = 24) for delay discounting and sign and magnitude effects for probability discounting. Participants completed delay and probability discounting tasks spanning rewards and losses; money, cocaine, and health outcomes; and magnitudes of $10, $100, and $1,000. Four primary findings emerged when controlling for other drug use. First, cocaine users pervasively discounted delayed consequences more than never users regardless of sign, magnitude, or commodity, with the possible exception of delay discounting of $1,000 health equivalences. Second, both groups discounted delayed rewards more than losses, with a similar trend for probability discounting. Third, magnitude effects in cocaine users for delayed and probabilistic outcomes were similar to those previously observed in never users and other-drug users. Fourth, cocaine users discounted cocaine-related outcomes more than money and health, with variable results comparing money and health. These data suggest that the behavioral processes of delay and probability discounting are qualitatively similar for cocaine users and never users. However, quantitatively, cocaine users generally showed greater delay discounting and similar probability discounting compared with never users. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Comparison of delay discounting of different outcomes in cigarette smokers, smokeless tobacco users, e-cigarette users, and non-tobacco users

Delay discounting is the process by which a commodity loses value as the delay to its receipt increases. Rapid discounting predicts various maladaptive behaviors including tobacco use. Typically, delay discounting of different outcomes has been compared between cigarette smokers and nonsmokers. To better understand the relationship of delay discounting to different modes of tobacco use, we examined the differences in delay discounting of different outcomes between cigarette smokers, smokeless tobacco users, e-cigarette users, and non-tobacco users. In the present study, all participants completed 8 titrating delay-discounting tasks: $100 gain, $500 gain, $500 loss, alcohol, entertainment, food, a temporary health gain, and a temporary cure from a disease. Non-tobacco users discounted most outcomes less than tobacco users overall; however, there were no differences in discounting among the different types of tobacco users. These results suggest that nicotine consumption of any kind is associated with a higher degree of impulsivity compared to non-tobacco users. Adoption of tobacco products that have been perceived as less harmful (e.g., e-cigarettes) is not associated with a baseline difference or decrease in delay discounting if adopted after a history of cigarette use.

Single- and cross-commodity delay discounting of money and e-cigarette liquid in experienced e-cigarette users

BACKGROUND

Delay discounting (DD) research has improved our understanding of important behavioral processes associated with tobacco use. Little research has explored DD among e-cigarette users, and these studies have exclusively examined money as the only available commodity. This secondary analysis of a laboratory study explored discounting for money and e-liquid among e-cigarette users using two single-commodity discounting (SCD) tasks and one cross-commodity discounting (CCD) task. A secondary goal was to explore the extent to which results from the SCD and CCD tasks were correlated to each other and with measures of e-cigarette use.

METHODS

E-cigarette users (N = 27) completed two SCD tasks and one CCD task. The SCD tasks assessed choices between various amounts of either money now versus money later (M-M) or e-liquid now versus e-liquid later (mL-mL). The CCD task assessed choices between e-liquid now versus money later (mL-M). Discounting results were compared using logk and AUClog.

RESULTS

Discounting was greatest in the mL-mL task, followed by the M-M task, and then the mL-M task. AUClog and logk were significantly correlated across all discounting tasks. Attempts to quit vaping was positively associated with logk and negatively associated with AUClog and in both SCD tasks.

CONCLUSIONS

E-cigarette users discount e-liquid more than money in a SCD task. However, when the two commodities, money and e-liquid (CCD), are compared the substance of abuse is discounted to a lesser extent. Interventions that provide alternative reinforcers to compete with the reinforcing effects of nicotine intake may be especially indicated for treating e-cigarette dependence.

Profiles of Impulsivity in Problematic Internet Users and Cigarette Smokers

Problematic Internet use (PIU) has been gradually recognized as a mental health issue among adolescents and young students. PIU shows many similarities with substance use disorders, but the shared and distinct mechanisms underlying them are unclear. The purpose of the current study was to explore the relationships between impulsive traits and PIU as well as cigarette smoking behaviors among young adults. Two independent samples of university students (N 1 = 1281, N 2 = 1034, respectively) over 3 years were assessed with multiple measurements of impulsivity, including the Barratt Impulsiveness Scale-11 (BIS-11), the UPPSP Impulsive Behaviors Scale (UPPSP), and the Delay-discounting Test (DDT). Logistic regression models revealed that across the two independent samples, BIS-11 Attentional Impulsiveness was the common trait positively predicting both PIU and cigarette smoking. While BIS-11 Motor Impulsiveness as well as UPPSP Lack of Perseverance, Lack of Premeditation, and Negative Urgency were the typical traits linked to PIU as positive predictors, UPPSP Sensation Seeking was the unique trait linked to cigarette smoking as a positive predictor. These results suggested that specific dimensions of impulsivity might be concurrently implicated in PIU and cigarette smoking among young adults, putatively representing important trait marks for addictive behaviors.

Delay discounting and e-cigarette use: An investigation in current, former, and never cigarette smokers

BACKGROUND

Cigarette smokers show greater delay discounting (devaluation of delayed consequences) than non-smokers, suggesting that rapid devaluation of the future contributes to tobacco use through a mechanism in which tobacco-related health consequences are too delayed to discourage smoking. However, little work has quantified delay discounting in relation to electronic cigarette (EC) use, a tobacco product that many users believe to pose fewer negative health consequences than cigarettes.

METHODS

We assessed discounting of delayed monetary rewards in a web-based sample of 976 participants, stratified by both EC use (current and never) and cigarette use (current, former, and never).

RESULTS

Controlling for demographic variance, current EC users generally showed greater discounting than never EC users (p = .019). Current cigarette smokers also showed greater discounting than former and never smokers (p < .001). However, the between-group difference for EC use was much smaller (η_p² = .006) than for cigarette use (η_p² = .026). Moreover, differences in discounting in relation to EC use were not statistically apparent in most pairwise comparisons. Most notably, the difference between former smokers who achieved smoking cessation by transitioning to ECs (i.e., exclusive EC users) and those who have never used ECs or cigarettes was nonsignificant and small (η_p² = .010).

CONCLUSIONS

The smaller effect size for the association between delay discounting and current EC use, relative to current cigarette use, suggests that public perception of ECs as a safer alternative to cigarettes attenuates the role of delay discounting in decisions to use ECs.