Changing Delay Discounting and Impulsive Choice: Implications for Addictions, Prevention, and Human Health

The functional connectivity between the dorsolateral prefrontal cortex and the medial prefrontal cortex underlying the association between self-control and delay discounting

Delay discounting is the tendency for people to devalue future rewards as the time required to obtain them increases over time. Self-control is the ability to regulate behavior, emotions and cognition to achieve goals or adhere to social norms despite temptations, impulses or distractions. Previous studies have found that self-control was negatively correlated with delay discounting. However, the neural mechanism underlying the relationship between self-control and delay discounting remains unclear. To address this question, we examined the neural basis of the relationship between self-control and delay discounting using voxel-based morphometry(VBM) and resting-state functional connectivity analysis(RSFC). The behavioral results demonstrated a negative correlation between delay discounting and self-control. Furthermore, the voxel-based morphometry results showed a positive correlation between self-control and gray matter volume in the dorsolateral prefrontal cortex(dlPFC). Moreover, self-control was positively correlated with functional connectivity between the medial prefrontal cortex(mPFC) and the dorsolateral prefrontal cortex. More importantly, the association between self-control and delay discounting was shown to be partially mediated by the functional connectivity between the dlPFC and mPFC. These findings suggested that dlPFC-mPFC functional connectivity could be the neural basis underlying the association between self-control and delay discounting, which provided novel insights into how self-control affected delay discounting and offered new explanations from a neural perspective.

The perceived controllability of negatively-valenced episodic future thinking modulates delay discounting

Intertemporal decision-making is important for both economy and physical health. Nevertheless, in daily life, individuals tend to prefer immediate and smaller rewards to delayed and larger rewards, which is known as delay discounting (DD). Episodic future thinking (EFT) has been proven to influence DD. However, there is still no inconsistent conclusion on the effect of negative EFT on DD. Considering the perceived controllability of negative EFT may address the issue (Controllability refers to the extent to which progress and result of an event could be controlled by ourselves). In the current study, we manipulated EFT conditions (baseline, neutral EFT, negative-controllable EFT and negative-uncontrollable EFT), delayed time (i.e. 1 week, 1 month, 3 months, 6 months, 1 year and 3 years) and reward magnitude (small, large). We mainly found that when experiencing negative-uncontrollable EFT compared to negative-controllable EFT in the delayed time of 6 months with large rewards, individuals chose more delayed rewards, suggesting that negative-uncontrollable EFT effectively reduced DD under conditions of both large-magnitude reward and longer delayed time. The current study provides new insight for healthy groups on optimising EFT. In that case, individuals are able to gain long-term benefits in financial management and healthcare.

Delay discounting is associated with addiction and mental health measures while controlling for health behaviors and health barriers in a large US sample

Background

Excessive discounting of future rewards [delay discounting (DD)] may be a transdiagnostic process and treatment target underlying behavioral health outcomes, including trauma, depression, anxiety, and problematic substance use. However, multiple health behaviors and barriers are also related to these outcomes, including social media usage, adverse childhood experiences (ACEs), sleep quality, healthcare access, housing status, and exercise. To extend research examining DD as transdiagnostic process, we recruited a large, heterogenous sample to examine the association between DD, problematic substance use, and mental health outcomes while controlling for certain health behaviors and health barriers.

Method

In a cross-sectional online survey of 3992 US residents, we administered validated measures of PTSD, depression, anxiety, and problematic alcohol, stimulant, and opioid use. Using linear or ordinal logistic models, scores for each outcome were regressed onto DD while controlling for demographics, health behaviors, and health barriers.

Results

Including only DD and demographics, DD was associated with each outcome at low effect sizes (ƒ2 = .013, OR range = 1.08-1.16). Except for opioid ASSIST scores, these relationships held when controlling for social media usage, sleep, housing status, healthcare access, ACEs, physical exercise, and demographic variables (ƒ2 = .002, OR range = 1.03-1.12), increasing confidence that DD concurrently and directly relates to four of these five clinical outcomes.

Discussion

These findings support the conceptualization of DD as a transdiagnostic process underlying certain psychopathologies and suggest targeting DD in co-occurring substance use disorder and/or mental health treatments may result in clinically significant outcomes.

Gamification and motivation: Impact on delay discounting performance

Delay discounting is a phenomenon strongly associated with impulsivity. However, in order for a measured discounting rate in an experiment to meaningfully generalize to choices made elsewhere in life, participants must provide thoughtful, engaged answers during the assessment. Classic discounting tasks may not optimize intrinsic motivation or enjoyment, and a participant who is disengaged from the task is likely to behave in a way that provides a biased estimate of their discounting function. We assessed degree of delay discounting in a task intended to vary level of participant motivation. This was accomplished by introducing varying levels of gamification, the application of game design principles to a non-game context. Experiment 1 compared three versions of the delay discounting task with differing degrees of gamification and compared performance and task enjoyment across those variations, while Experiment 2 used two conditions (one gamified, one not). Participants found more gamified versions of the task more enjoyable than the other conditions, without producing substantial between-group differences in most cases. Thus, more polished task gameplay can provide a more enjoyable experience for participants without undermining delay discounting effects commonly reported in the literature. We also found that in all experimental conditions, higher levels of interest in or enjoyment of the task tended to be associated with more rapid discounting. This may suggest that low task motivation may result in less impulsive choice and suggests that participants who find delay discounting experiments sufficiently boring may bias assessments of value across delays.

Initial evidence of delay discounting's predictive utility for alcohol self-administration in ecologically valid contexts among young adults who drink heavily

BACKGROUND

While delay discounting is robustly associated with alcohol use disorder, whether discounting predicts real-time alcohol use behaviors is unclear. Existing support comes from laboratory studies using intravenous alcohol self-administration methods, thus limiting ecological validity and generalizability. The present study evaluated whether delay discounting predicted real-time alcohol use in naturalistic settings with and without probabilistic negative consequences for consuming larger amounts of alcohol.

METHODS

This secondary analysis utilized data from three laboratory alcohol self-administration studies with young adults who engaged in frequent heavy drinking (N=206, 45% female). Participants completed a delay discounting measure before an alcohol self-administration session in an actual or simulated bar with (n=187) or without (n=19) probabilistic negative consequences (compensation loss) tied to performance on cognitive and psychomotor tasks after alcohol self-administration. Bootstrapped (unstandardized) coefficient estimates and 95% confidence intervals were utilized due to the sample size discrepancy.

RESULTS

Multiple regressions revealed that delay discounting did not significantly predict estimated blood alcohol concentration (eBAC) or number of drinks consumed when procedures included probabilistic negative consequences. Among participants who completed procedures without probabilistic negative consequences, delay discounting was positively associated with peak eBAC.

CONCLUSION

Counter to hypotheses, steeper delay discounting did not predict real-time alcohol use in contexts with probabilistic negative consequences, whereas preliminary evidence suggests that delay discounting predicts real-time alcohol use behaviors in contexts without probabilistic negative consequences. The specific discounting task may have impacted study findings, thus future research should consider how the sign (gain vs. loss), outcome certainty, and delay relate to alcohol consumption.

Designing and Validating a Novel Method for Assessing Delay Discounting Associated With Health Behaviors: Ecological Momentary Assessment Study

BACKGROUND

Delay discounting quantifies an individual's preference for smaller, short-term rewards over larger, long-term rewards and represents a transdiagnostic factor associated with numerous adverse health outcomes. Rather than a fixed trait, delay discounting may vary over time and place, influenced by individual and contextual factors. Continuous, real-time measurement could inform adaptive interventions for various health conditions.

OBJECTIVE

The goals of this paper are 2-fold. First, we present and validate a novel, short, ecological momentary assessment (EMA)-based delay discounting scale we developed. Second, we assess this tool's ability to reproduce known associations between delay discounting and health behaviors (ie, substance use and craving) using a convenience-based sample.

METHODS

Participants (N=97) were adults (age range 18-71 years), recruited on social media. In phase 1, data were collected on participant sociodemographic characteristics, and delay discounting was evaluated via the traditional Monetary Choice Questionnaire (MCQ) and our novel method (ie, 7-item time-selection and 7-item monetary-selection scales). During phase 2 (approximately 6 months later), participants completed the MCQ, our novel delay discounting measures, and health outcomes questions. The correlations between our method and the traditional MCQ within and across phases were examined. For scale reduction, a random number of items were iteratively selected, and the correlation between the full and random scales was assessed. We then examined the association between our time- and monetary-selection scales assessed during phase 2 and the percentage of assessments that participants endorsed using or craving alcohol, tobacco, or cannabis.

RESULTS

In total, 6 of the 7 individual time-selection items were highly correlated with the full scale (r>0.89). Both time-selection (r=0.71; P<.001) and monetary-selection (r=0.66; P<.001) delay discounting rates had high test-retest reliability across phases 1 and 2. Phase 1 MCQ delay discounting function highly correlated with phase 1 (r=0.76; P<.001) and phase 2 (r=0.45; P<.001) time-selection delay discounting scales. One or more randomly chosen time-selection items were highly correlated with the full scale (r>0.94). Greater delay discounting measured via the time-selection measure (adjusted mean difference=5.89, 95% CI 1.99-9.79), but not the monetary-selection scale (adjusted mean difference=-0.62, 95% CI -3.57 to 2.32), was associated with more past-hour tobacco use endorsement in follow-up surveys.

CONCLUSIONS

This study evaluated a novel EMA-based scale's ability to validly and reliably assess delay discounting. By measuring delay discounting with fewer items and in situ via EMA in natural environments, researchers may be better able to identify individuals at risk for poor health outcomes.

White matter-based brain network topological properties associated with individual impulsivity

Delay discounting (DD), a parameter derived from the intertemporal choice task, is a representative behavioral indicator of choice impulsivity. Previous research reported not only an association between DD and impulsive control disorders and negative health outcomes but also the neural correlates of DD. However, to date, there are few studies investigating the structural brain network topologies associated with individual differences in DD and whether self-reported measures (BIS-11) of impulsivity associated with DD share the same or distinct neural mechanisms is still unclear. To address these issues, here, we combined graph theoretical analysis with diffusion tensor imaging to investigate the associations between DD and the topological properties of the structural connectivity network and BIS-11 scores. Results revealed that people with a steep DD (greater impatience) had decreased small-worldness (a shift toward weaker small-worldnization) and increased degree centrality in the medial superior prefrontal cortex, associated with subjective value in the task. Though DD was associated with the BIS-11 motor impulsiveness subscale, this subscale was linked to topological properties different from DD; that is, high motor impulsiveness was associated with decreased local efficiency (less segregation) and decreased degree centrality in the precentral gyrus, involved in motor control. These findings provide insights into the systemic brain characteristics underlying individual differences in impulsivity and potential neural markers which could predict susceptibility to impulsive behaviors.

Mechanisms of impulsive choice: Experiments to explore and models to map the empirical terrain

Impulsive choice is preference for a smaller-sooner (SS) outcome over a larger-later (LL) outcome when LL choices result in greater reinforcement maximization. Delay discounting is a model of impulsive choice that describes the decaying value of a reinforcer over time, with impulsive choice evident when the empirical choice-delay function is steep. Steep discounting is correlated with multiple diseases and disorders. Thus, understanding the processes underlying impulsive choice is a popular topic for investigation. Experimental research has explored the conditions that moderate impulsive choice, and quantitative models of impulsive choice have been developed that elegantly represent the underlying processes. This review spotlights experimental research in impulsive choice covering human and nonhuman animals across the domains of learning, motivation, and cognition. Contemporary models of delay discounting designed to explain the underlying mechanisms of impulsive choice are discussed. These models focus on potential candidate mechanisms, which include perception, delay and/or reinforcer sensitivity, reinforcement maximization, motivation, and cognitive systems. Although the models collectively explain multiple mechanistic phenomena, there are several cognitive processes, such as attention and working memory, that are overlooked. Future research and model development should focus on bridging the gap between quantitative models and empirical phenomena.

Are the attention checks embedded in delay discounting tasks a valid marker for data quality?

To ensure good quality delay discounting (DD) data in research recruiting via crowdsourcing platforms, including attention checks within DD tasks have become common. These attention checks are typically identical in format to the task questions but have one sensical answer (e.g., "Would you prefer $0 now or $100 in a month?"). However, the validity of these attention checks as a marker for DD or overall survey data quality has not been directly examined. To address this gap, using data from two studies (total N = 700), the validity of these DD attention checks was tested by assessing performance on other non-DD attention checks and data quality measures both specific to DD and overall survey data (e.g., providing nonsystematic DD data, responding inconsistently in questionnaires). We also tested whether failing the attention checks was associated with degree of discounting or other participant characteristics to screen for potential bias. While failing the DD attention checks was associated with a greater likelihood of nonsystematic DD data, their discriminability was inadequate, and failure was sometimes associated with individual differences (suggesting that data exclusion might introduce bias). Failing the DD attention checks was also not associated with failing other attention checks or data quality indicators. Overall, the DD attention checks do not appear to be an adequate indicator of data quality on their own, for either the DD task or surveys overall. Strategies to enhance the validity of DD attention checks and data cleaning procedures are suggested, which should be evaluated in future research. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Delay Discounting for HIV/STI Testing

Introduction

Wait time in healthcare is an important barrier to HIV/STI testing. Using a delay discounting approach, the current study examined a systematic reduction in testing likelihood as a function of delay (wait time) until testing.

Methods

In Study 1 (N = 421; data collected in 2019), participants were randomly assigned to either a chlamydia/gonorrhea group or HIV group. A delay discounting task asked them to report how likely they would get tested for the assigned STI if they had to wait for the test (the delay durations varied within persons). In Study 2 (N = 392; data collected in 2020), we added a smaller, sooner outcome (consultation without testing) and tested whether the effect of delay was mediated by perceived severity of the STIs.

Results

In both studies, the subjective value of a delayed STI test was discounted. That is, people were less likely to undergo STI testing as the delay to STI testing increased. The chlamydia/gonorrhea group discounted delayed testing more than the HIV group (i.e., the effect of delay on testing decisions was stronger for the former). This effect was statistically mediated by perceived severity.

Conclusions

We found evidence for delay discounting for HIV/STI testing and that testing decisions were more susceptible to delay when the test was for relatively mild STIs.

Policy Implications

Even mild STIs can cause serious health damage if left untreated. The findings provide strong argument for policies aimed to reduce wait times in healthcare, especially for relatively mild STIs.

Delay discounting as a behavioral phenotype associated with social rank in female and male cynomolgus monkeys: Correlation with kappa opioid receptor availability

Cocaine use disorder (CUD) is a significant problem worldwide, with no FDA-approved treatments. Epidemiological data indicate that only about 17 % of people that use cocaine will meet DSM criteria for CUD. Thus, the identification of biomarkers predictive of eventual cocaine use may be of great value. Two potentially useful predictors of CUD are social hierarchies in nonhuman primates and delay discounting. Both social rank and preference for a smaller, immediate reinforcer relative to a larger, delayed reinforcer have been predictive of CUD. Therefore, we wanted to determine if there was also a relationship between these two predictors of CUD. In the present study, monkeys cocaine-naive responded under a concurrent schedule of 1- vs. 3-food pellets and delivery of the 3-pellet option was delayed. The primary dependent variable was the indifference point (IP), which is the delay that results in 50 % choice for both options. In the initial determination of IP, there were no differences based on sex or social rank of the monkeys. When the delays were redetermined after ~25 baseline sessions (range 5-128 sessions), dominant females and subordinate males showed the largest increases in IP scores from the first determination to the second. Because 13 of these monkeys had prior PET scans of the kappa opioid receptor (KOR), we examined the relationship between KOR availability and IP values and found that the change in IP scores from the first to the second determination significantly negatively predicted average KOR availability in most brain regions. Future studies will examine acquisition to cocaine self-administration in these same monkeys, to determine if IP values are predictive of vulnerability to cocaine reinforcement.

Motivational and myopic mechanisms underlying dopamine medication-induced impulsive-compulsive behaviors in Parkinson's disease

Introduction

Dopaminergic medications can trigger impulsive-compulsive behaviors (ICBs) in pre-disposed patients with Parkinson's disease (PD), but what this implies on a neurocognitive level is unclear. Previous findings highlighted potentially exacerbated incentive motivation (willingness to work for rewards) and choice impulsivity (preferring smaller, immediate rewards over larger, delayed rewards) in PD patients with ICBs (PD + ICBs).

Methods

To deeply understand this evidence, we studied 24 PD + ICBs and 28 PD patients without ICBs (PD-ICBs). First of all, patients underwent the assessment of impulsivity traits, mood, anxiety, and addiction condition. We further administered robust objective and subjective measures of specific aspects of motivation. Finally, we explored whether these processes might link to any heightened antisocial behavior (aggression and risky driving) in PD + ICBs.

Results

High levels of positive urgency trait characterized PD + ICBs. They choose to exert more effort for rewards under the conditions of low and medium reward probability and as reward magnitude increases. Findings on choice impulsivity show a great tendency to delay discounting in PD + ICBs, other than a high correlation between delay and probability discounting. In addition, we found what appears to be the first evidence of heightened reactive aggression in PD patients with ICBs. Exacerbated incentive motivation and delay discounting trended toward positively predicting reactive aggression in PD + ICBs.

Discussion

Our promising results suggest that there might be immense value in future large-scale studies adopting a transdiagnostic neurocognitive endophenotype approach to understanding and predicting the addictive and aggressive behaviors that can arise from dopaminergic medication in PD.

Sequential delay and probability discounting tasks in mice reveal anchoring effects partially attributable to decision noise

Delay discounting and probability discounting decision making tasks in rodent models have high translational potential. However, it is unclear whether the discounted value of the large reward option is the main contributor to variability in animals' choices in either task, which may limit translation to humans. Male and female mice underwent sessions of delay and probability discounting in sequence to assess how choice behavior adapts over experience with each task. To control for "anchoring" (persistent choices based on the initial delay or probability), mice experienced "Worsening" schedules where the large reward was offered under initially favorable conditions that became less favorable during testing, followed by "Improving" schedules where the large reward was offered under initially unfavorable conditions that improved over a session. During delay discounting, both male and female mice showed elimination of anchoring effects over training. In probability discounting, both sexes of mice continued to show some anchoring even after months of training. One possibility is that "noisy", exploratory choices could contribute to these persistent anchoring effects, rather than constant fluctuations in value discounting. We fit choice behavior in individual animals using models that included both a value-based discounting parameter and a decision noise parameter that captured variability in choices deviating from value maximization. Changes in anchoring behavior over time were tracked by changes in both the value and decision noise parameters in delay discounting, but by the decision noise parameter in probability discounting. Exploratory decision making was also reflected in choice response times that tracked the degree of conflict caused by both uncertainty and temporal cost, but was not linked with differences in locomotor activity reflecting chamber exploration. Thus, variable discounting behavior in mice can result from changes in exploration of the decision options rather than changes in reward valuation.

Applied Quantitative Analysis of Behavior: What It Is, and Why We Care-Introduction to the Special Section

Science evolves from prior approximations of its current form. Interest in changes in species over time was not a new concept when Darwin made his famous voyage to the Galapagos Islands; concern with speciation stretches back throughout the history of modern thought. Behavioral science also does and must evolve. Such change can be difficult, but it can also yield great dividends. The focus of the current special section is on a common mutation that appears to have emerged across these areas and the critical features that define an emerging research area-applied quantitative analysis of behavior (AQAB). In this introduction to the "Special Issue on Applications of Quantitative Methods," we will outline some of the common characteristics of research in this area, an exercise that will surely be outdated as the research area continues to progress. In doing so, we also describe how AQAB is relevant to theory, behavioral pharmacology, applied behavior analysis, and health behaviors. Finally, we provide a summary for the articles that appear in this special issue. The authors of these papers are all thinking outside the Skinner box, creating new tools and approaches, and testing them against relevant data. If we can keep up this evolution of methods and ideas, behavior analysis will regain its place at the head of the table!

The effects of cueing episodic future thinking on delay discounting in children, adolescents, and adults

Discounting the value of delayed rewards such that even a relatively small, immediately available reward is preferred to a larger delayed reward is a commonly observed human trait. Children are particularly steep discounters of delayed rewards as evidenced by delay of gratification studies. In recent years, however, a growing literature indicates that cueing individuals to imagine personal future events attenuates their discounting of delayed rewards. The present studies extend this literature by examining whether cueing future thinking promotes patient choices in children and adolescents. In Experiment 1 we found that cueing future thinking had no effect on 8-11-year-olds' (n = 177) delay discounting of either real or hypothetical rewards. In Experiment 2 we found that cueing adolescents (12-14-year-olds, n = 126) and adults (n = 122) to think about personal future events decreased their discounting of delayed rewards relative to three other conditions: a no cue control, an episodic memory condition and a novel 'future other' condition in which individuals imagine future events that might happen to a significant other person in their life. Cueing adults and adolescents to think about personal future events did not however affect how connected they felt to their future selves or their subjective sense of how close future time points felt to them - two constructs that have previously been shown to be related to delay discounting.

Effects of immediate-reinforcement training on delay discounting behavior in rats

Chronic exposure to delayed reinforcement has been shown to increase choice for larger, later reinforcement in a subsequent delay discounting task. In the 3 experiments presented in this paper, the opposite was tested: effects of chronic exposure to immediate reinforcement on choice in a subsequent delay discounting task. In Experiment 1, larger, later reinforcement choice was significantly reduced as a result of exposure to immediate reinforcement, compared to a maturation/handle control group, in experienced, male Lewis rats. In Experiment 2, with naive male and female Wistar rats, and Experiment 3, with naïve male Long Evans rats, the impact of exposure to immediate reinforcement was less robust, but directionally consistent with results from Experiment 1. These results align with some previous work reporting that exposure to immediate reinforcement may decrease choice for larger, later reinforcement in a delay discounting task, and/or blunt maturational increases in choice for larger, later reinforcement. These findings have implications for future research investigating experience-based interventions to manipulate delay discounting behavior. They also have clinical implications for understanding and treating disorders involving maladaptive choice.

A Review of the Concept of Impulsivity: An Evolutionary Perspective

Impulsivity is a central concept for many psychological models and interventions. Despite extensive research, the concept of impulsivity lacks clarity due to the diversity of definitions provided. The aims of this study were to conduct a concept analysis of impulsivity to provide a clear and workable definition of impulsivity for future nursing research. This study used Rodgers' evolutionary concept analysis approach to analyze 37 articles from various disciplines. Our analysis offers promising direction in refining the concept. The findings can drive future research and enhance nurse researchers' ability to attend and explore health-related issues associated with the concept.

Future Thinking Priming Especially Effective at Modifying Delay Discounting Rates among Cigarette Smokers

BACKGROUND

Tobacco use remains one of the world's greatest preventable causes of death and disease. While most smokers want to quit, few are successful, highlighting a need for novel therapeutic approaches to support cessation efforts. Lower delay discounting (DD) rates are associated with increased smoking cessation success. Future thinking priming (FTP) reliably reduces DD rates in large populations. Smokers consistently discount more than nonsmokers, and evidence suggests that changes in DD rates are rate dependent. This study examined whether smoking status moderated the effect of FTP on DD rates and, if so, if the moderation effect could be attributed to differences in baseline rates of DD.

METHODS

Moderation analysis was conducted to determine whether the effect of FTP, versus neutral priming (NP), on DD differed among smokers and nonsmokers.

RESULTS

Smoking status moderated the effect of condition (FTP vs. NP) on post-intervention DD scores (b = -0.2919, p = 0.0124) and DD change scores (b = -0.2975, p = 0.0130). There was no evidence of rate dependence effects in the current sample.

CONCLUSIONS

FTP had a greater effect on decreasing DD rates among smokers than nonsmokers. FTP is effective and simple to administer, which makes it a promising therapeutic approach for aiding smoking cessation.

Temporal discounting as a candidate behavioral marker of obesity

Although obesity is a result of processes operating at multiple levels, most forms result from decision-making behavior. The aim of this review was to examine the candidacy of temporal discounting (TD) (i.e. the reduction in the value of a reinforcer as a function of the delay to its receipt) as a behavioral marker of obesity. For this purpose, we assessed whether TD has the ability to: identify risk for obesity development, diagnose obesity, track obesity progression, predict treatment prognosis/outcomes, and measure treatment effectiveness. Three databases (Pubmed, PsycINFO, and Web of Science) were searched using a combination of terms related to TD and obesity. A total of 153 papers were reviewed. Several areas show strong evidence of TD's predictive utility as a behavioral marker of obesity (e.g., distinguishing obese from non obese). However, other areas have limited and/or mixed evidence (e.g., predicting weight change). Given the positive relationship for TD in the majority of domains examined, further consideration for TD as a behavioral marker of obesity is warranted.

Reinforcer pathology in cocaine use disorder: Temporal window determines cocaine valuation

AIMS

The Experimental Medicine Approach offers a unique perspective to determine clinical behavior change by engaging a target underlying the cause of a disorder. The present work engaged a novel target of addiction, Reinforcer Pathology, in two studies to test changes in behavior among individuals with cocaine use disorder.

METHODS

In Study 1, n = 44 participants engaged the temporal window with episodic future thinking (EFT), a positive prospection exercise. Changes in temporal view and cocaine valuation were tested using delay discounting and behavioral economic demand, respectively. Additionally, a computational model assessed the relative reliance on the near- and far-sighted systems during EFT. In Study 2, n = 71 engaged the temporal window with a negatively-valenced hurricane scenario to test the opposite effects on window length and cocaine valuation.

RESULTS

Results demonstrated systematic and symmetrical engagement of the behavioral target. Study 1 robustly replicated previous work, wherein EFT lengthened the temporal window and decreased cocaine valuation. Moreover, EFT increased the weighting of the modeled far-sighted system, increasing the relative impact of long-term discounting decisions. Study 2 produced opposite outcomes, shortened temporal window and increased cocaine valuation.

CONCLUSIONS

This approximately equal and opposite reaction to the manipulations supports reinforcer pathology theory and implicates the temporal window over which rewards are valued as a target to be pushed and pulled to produce clinically meaningful behavior change. Using the Experimental Medicine Approach as a guide, future work should identify new potential interventions to engage reinforcer pathology and use the clinically relevant outcomes as a litmus test for mechanism.

Neural networks during delay discounting as trans-disease marker: A meta-analytical review

Delay discounting reflects a devaluation of delayed long-term benefits but pursuing immediate rewards. Higher discounting rates (h-DR) are found ubiquitous in many diseases and unhealthy conditions, particularly in addiction disorder (AD), attention-deficit/hyperactivity disorder (ADHD), and obesity. Thus, h-DR was considered to be a common benchmark across many diseases facilitating to understand one disease to relevant others, which was called trans-disease process. However, the common and specific neural biomarkers associated with this process has not yet been studied well. We performed a voxel-wise task-related neuroimaging meta-analysis to clarify the neural pattern of trans-disease process across AD, ADHD and obesity. We recruited 19 eligible papers, including 9 AD papers (154 patients), 6 ADHD papers (106 patients) and 4 obesity studies (94 patients). Neuroimaging meta-analysis demonstrated the presence of neural biomarkers of trans-disease process: these patients showed inadequate brain response in caudate, ventromedial and dorsolateral prefrontal cortex (dlPFC) than do of healthy controls (HCs). Disease-specific neural patterns were also found, with prominent hypoactivation in parahippocampal-striatum network for AD, hyperactivation in dopamine-projection striatum network for ADHD and decreased activity in dorsal anterior cingulate cortex and dlPFC for obesity. This study provided robust evidence to reveal the neural substrates of trans-disease process, as well further promoted the triple brain network model in favor of the theoretical developments of these neuropsychiatric disorders.

Pharmacokinetics trumps pharmacodynamics during cocaine choice: a reconciliation with the dopamine hypothesis of addiction

Cocaine is known to increase brain dopamine at supranormal levels in comparison to alternative nondrug rewards. According to the dopamine hypothesis of addiction, this abnormally large dopamine response would explain why cocaine use is initially highly rewarding and addictive. Though resting on solid neuroscientific foundations, this hypothesis has nevertheless proven difficult to reconcile with research on cocaine choice in experimental animals. When facing a choice between an intravenous bolus of cocaine and a nondrug alternative (e.g., sweet water), both delivered immediately after choice, rats do not choose the drug, as would be predicted, but instead develop a strong preference for the nondrug alternative. Here we report evidence that reconciles this finding with the dopamine hypothesis of addiction. First, a systematic literature analysis revealed that the delays of effects of intravenous cocaine on nucleus accumbens dopamine are of the order of tens of seconds and are considerably longer than those of nondrug reward. Second, this was confirmed by measuring response times to cocaine omission during self-administration as a behavioral proxy of these delays. Finally, when the influence of the drug delays was reduced during choice by adding an increasing delay to both the drug and nondrug rewards, rats shifted their choice to cocaine. Overall, this study suggests that cocaine is indeed supranormal in reward magnitude, as postulated by the dopamine hypothesis of addiction, but is less preferred during choice because its pharmacokinetics makes it an inherently more delayed reward than the alternative. Reframing previous drug choice studies in rats as intertemporal choice studies reveals that the discounting effects of delays spare no rewards, including supranormal ones, and that during choice, pharmacokinetics trumps pharmacodynamics.

Food Addiction and Psychosocial Adversity: Biological Embedding, Contextual Factors, and Public Health Implications

The role of stress, trauma, and adversity particularly early in life has been identified as a contributing factor in both drug and food addictions. While links between traumatic stress and substance use disorders are well documented, the pathways to food addiction and obesity are less established. This review focuses on psychosocial and neurobiological factors that may increase risk for addiction-like behaviors and ultimately increase BMI over the lifespan. Early childhood and adolescent adversity can induce long-lasting alterations in the glucocorticoid and dopamine systems that lead to increased addiction vulnerability later in life. Allostatic load, the hypothalamic-pituitary-adrenal axis, and emerging data on epigenetics in the context of biological embedding are highlighted. A conceptual model for food addiction is proposed, which integrates data on the biological embedding of adversity as well as upstream psychological, social, and environmental factors. Dietary restraint as a feature of disordered eating is discussed as an important contextual factor related to food addiction. Discussion of various public health and policy considerations are based on the concept that improved knowledge of biopsychosocial mechanisms contributing to food addiction may decrease stigma associated with obesity and disordered eating behavior.

Pilot trial investigating a brief behavioral economic intervention as an adjunctive treatment for alcohol use disorder

OBJECTIVE

Behavioral economic research suggests that increasing the salience of a delayed reward may improve capacity for delaying gratification and increase behavior allocated toward obtaining larger, delayed substance-free reward rather than smaller, more immediate reward such as alcohol use. This study aimed to improve the efficacy of outpatient alcohol use disorder (AUD) treatment by adding elements that target behavioral economic mechanisms of change.

METHOD

Forty-one (N = 41) adults in outpatient AUD treatment were recruited and 37 participants were retained at follow-up. Following baseline assessment, participants received either the Substance Free Activity Session (SFAS), a single-session behavioral economic-informed intervention focused on increasing future orientation and engagement in values-based substance-free activities or a health education control intervention. Participants in both conditions received weekly prompts (via text or email) relevant to their respective intervention for four weeks. Participants (68.3% male; 70.7% Caucasian, M age = 38.24, SD = 12.69) reported an average of 3.95 (SD = 4.72) binge drinking episodes (4/5 drinks per occasion for a woman/man) and 5.05 (SD = 5.32) drinks per drinking day 30-days prior to treatment entry.

RESULTS

The study provided initial support for the feasibility and acceptability of implementing the SFAS within a treatment setting. Participants reported high levels of satisfaction with the SFAS (M = 9.08 (SD = 0.94), on a scale of 1-10). At 3-month follow-up, the SFAS was associated with reductions in the proportion of activity participation and enjoyment (reinforcement) related to substance-use relative to substance-free activities and in alcohol demand compared to control.

CONCLUSION

These preliminary results provide initial support for targeting behavioral economic mechanisms of change in an outpatient AUD treatment with a single-session intervention plus remote delivery of booster prompts.

Deliberating trade-offs with the future

Many fundamental choices in life are intertemporal: they involve trade-offs between sooner and later outcomes. In recent years there has been a surge of interest into how people make intertemporal decisions, given that such decisions are ubiquitous in everyday life and central in domains from substance use to climate change action. While it is clear that people make decisions according to rules, intuitions and habits, they also commonly deliberate over their options, thinking through potential outcomes and reflecting on their own preferences. In this Perspective, we bring to bear recent research into the higher-order capacities that underpin deliberation-particularly those that enable people to think about the future (prospection) and their own thinking (metacognition)-to shed light on intertemporal decision-making. We show how a greater appreciation for these mechanisms of deliberation promises to advance our understanding of intertemporal decision-making and unify a wide range of otherwise disparate choice phenomena.

A time-based intervention to treat impulsivity in male and female rats

Time-based interventions have emerged as promising treatments for disorders associated with impulsivity. These interventions can be implemented to test their efficacy in preventing or treating impulsive choice in animal models of diseases related to impulsivity such as drug abuse. Impulsive choice is typically defined as choosing a smaller-sooner (SS) reward over a larger-later (LL) reward when the LL is relatively more optimal. Previous research has shown that these interventions promote LL choices in males and females, but sex differences have not been assessed. Because sex differences can complicate the application of therapies, it is critical to compare the effects of the intervention in males and females. The intervention group received exposure to 10-s and 30-s interval schedules, and the control rats received no delay to reward. Different impulsive choice tasks were used to assess the intervention efficacy across the two experiments. Following the intervention, reductions in impulsive choice were found in male and female rats, but the degree of improvement was inconsistent across sex and task. Bayesian analyses that combined the results revealed robust evidence of an overall intervention effect with the intervention group showing greater self-control, but there was no evidence for the intervention affecting males and females differently. Taken together, these results suggest that time-based interventions are effective tools to treat impulsivity in both males and females and offer promising translational capability to humans.

A web-based episodic specificity and future thinking session modulates delay discounting in cannabis users

Episodic future thinking (EFT), a brief intervention involving mental simulation of positive future events, improves delay discounting (DD) in nicotine and alcohol dependent individuals. This study is the first to assess effects of a single-session, online episodic training (ET) on constructs that might impact cannabis use and cannabis use disorder. A sample of 200 active cannabis users recruited via Amazon Mechanical Turk were randomized to an EFT group (n = 102) or an episodic recent thinking control group (ERT; n = 98). A novel episodic specificity induction (ES) was included to enhance quality of episodic thinking for the ET group, and an ES attention control was provided to the ERT group (control training group; CT). Quality and manipulation ratings of event excitement, vividness, importance, and enjoyment of trainings were collected in addition to DD tasks (gains and losses) and readiness to change cannabis use. The ET group reported higher overall quality and manipulation ratings than did the CT group (p < .001, d = 0.79). DD of gains was lower in the ET relative to those of the CT group after controlling for relevant variables (p = .003, d = 0.48), unlike DD of losses (p = .50, d = 0.11). The ET group showed larger pre/post increases in readiness to change, but they were not statistically significant (p = .069, d = 0.26). These effects, following a session of online ET, suggests that ET may positively impact factors related to reduction in cannabis use. Differential effects of EFT and ES components on DD and the development of ET as an adjunctive mHealth intervention targeting reduction in cannabis use appears warranted. (PsycInfo Database Record (c) 2020 APA, all rights reserved).