Increasing the Value of an Alternative Monetary Reinforcer Reduces Cigarette Choice in Adolescents

Contextual and psychosocial factors influencing drug reward in humans: The importance of non-drug reinforcement

The reinforcing efficacy, or behavior-strengthening effect, of a substance is a critical determinant of substance use typically quantified by measuring behavioral allocation to the substance under schedules of reinforcement with escalating response requirements. Although responses on these tasks are often used to indicate stable reinforcing effects or trait-level abuse potential for an individual, task designs often demonstrate within-person variability across varying degrees of a constraint within experimental procedures. As a result, quantifying behavioral allocation is an effective approach for measuring the impact of contextual and psychosocial factors on substance reward. We review studies using laboratory self-administration, behavioral economic purchase tasks, and ambulatory assessments to quantify the impact of various contextual and psychosocial factors on behavioral allocation toward consumption of a substance. We selected these assessment approaches because they cover the translational spectrum from experimental control to ecological relevance, with consistent support across these approaches representing greater confidence in the effect. Conceptually, we organized factors that influence substance value into two broad categories: factors that influence the cost/benefit ratio of the substance (social context, stress and affect, cue exposure), and factors that influence the cost/benefit ratio of an alternative (alternative non-drug reinforcers, alternative drug reinforcers, and opportunity costs). We conclude with an overview of future research directions and considerations for clinical application.

Enhanced decision-making in nicotine dependent individuals who abstain: A computational analysis using Hierarchical Drift Diffusion Modeling

BACKGROUND

Variability in decision-making capacity and reward responsiveness may underlie differences in the ability to abstain from smoking. Computational modeling of choice behavior, as with the Hierarchical Drift Diffusion Model (HDDM), can help dissociate reward responsiveness from underlying components of decision-making. Here we used the HDDM to identify which decision-making or reward-related parameters, extracted from data acquired in a reward processing task, contributed to the ability of people who smoke that are not seeking treatment to abstain from cigarettes during a laboratory task.

METHODS

80 adults who smoke cigarettes completed the Probabilistic Reward Task (PRT) - a signal detection task with a differential reinforcement schedule - following smoking as usual, and the Relapse Analogue Task (RAT) - a task in which participants could earn money for delaying smoking up to 50min - after a period of overnight abstinence. Two cohorts were defined by the RAT; those who waited either 0-min (n=36) or the full 50-min (n=44) before smoking.

RESULTS

PRT signal detection metrics indicated all subjects learned the task contingencies, with no differences in response bias or discriminability between the two groups. However, HDDM analyses indicated faster drift rates in 50-min vs. 0-min waiters.

CONCLUSIONS

Relative to those who did not abstain, computational modeling indicated that people who abstained from smoking for 50min showed faster evidence accumulation during reward-based decision-making. These results highlight the importance of decision-making mechanisms to smoking abstinence, and suggest that focusing on the evidence accumulation process may yield new targets for treatment.

A preliminary investigation of schedule parameters on cocaine abstinence in contingency management

Contingency management (CM) interventions are the most effective psychosocial interventions for substance use disorders. However, further investigation is needed to create the most robust intervention possible. This study investigated the effects of 1) reinforcer magnitude; and 2) fixed and escalating and resetting incentives on cocaine abstinence in an outpatient trial. In this analysis, 34 treatment-seeking individuals with Cocaine Use Disorder received either high or low value incentives for providing a benzoylecgonine-negative urine sample or were in a control condition and received incentives for providing a urine sample regardless of the results. Participants received either escalating and resetting incentives, wherein the value of each incentive increased with consecutive negative samples and reset to the initial level upon a positive sample (Experiment 1), or fixed incentives, wherein they received the same value incentive for each negative urine sample they provided (Experiment 2). Large incentives produced more abstinence, although escalating and resetting reinforcer values did not have a differential effect. Large, fixed incentives promoted abstinence faster than other reinforcers, whereas smaller incentives resulted in poor abstinence and took many visits to achieve initial abstinence. Future research comparing different schedules on cocaine abstinence in a randomized control trial with a larger sample size is required.

The effects of large, small, and thinning magnitudes of alternative reinforcement on resurgence

Resurgence refers to an increase of a previously reinforced target behavior following the worsening of conditions for a more recently reinforced alternative behavior. There is evidence to suggest that alternative reinforcers of greater magnitude are more effective at reducing target responding but may also result in more resurgence when removed. Similar effects have been observed with high rates of alternative reinforcement. However, in clinical settings, reinforcement rate thinning is used to reduce the likelihood of resurgence associated with higher rates of alternative reinforcement. Given the clinical importance of alternative reinforcer magnitude, it is necessary to evaluate how reinforcer magnitude thinning may impact resurgence as well. Following Phase 1 in which target responding was reinforced, rats earned either large (six pellets), small (one pellet), or thinned (reduced from six pellets to one across sessions) magnitude reinforcement for alternative responding during target-response extinction in Phase 2. Then, alternative responding was placed on extinction for all groups in Phase 3. Target responding was comparably elevated at the end of Phase 2 for groups Small and Thin compared to group Large. In Phase 3, resurgence was evident only in group Large but target responding remained relatively elevated in groups Small and Thin. These results provide additional evidence of the important interplay between conditions of alternative reinforcement and the persistence and resurgence of target responding.

Associations between the Brief Assessment of Alcohol Demand (BAAD) questionnaire and alcohol use disorder severity in UK samples of student and community drinkers

Value based choice and compulsion theories of addiction offer distinct explanations for the persistence of alcohol use despite harms. Choice theory argues that problematic drinkers ascribe such high value to alcohol that costs are outweighed, whereas compulsion theory argues that problematic drinkers discount costs in decision making. The current study evaluated these predictions by testing whether alcohol use disorder (AUD) symptom severity (indexed by the AUDIT) was more strongly associated with the intensity item (maximum alcohol consumption if free, indexing alcohol value) compared to the breakpoint item (maximum expenditure on a single drink, indexing sensitivity to monetary costs) of the Brief Assessment of Alcohol Demand (BAAD) questionnaire, in student (n = 579) and community (n = 120) drinkers. The community sample showed greater AUD than the student sample (p = .004). In both samples, AUD severity correlated with intensity (students, r = 0.63; community, r = 0.47), but not with breakpoint (students, r = -0.01; community, r = 0.12). Similarly, multiple regression analyses indicated that AUD severity was independently associated with intensity (student, ΔR² < 0.20, p < .001; community, ΔR² = 0.09, p = .001) but not breakpoint (student, ΔR² = 0.003, p = .118; community ΔR² = 0.01, p = .294). There was no difference between samples in the strength of these associations. The value ascribed to alcohol may play a more important role in AUD severity than discounting of alcohol-associated costs (compulsivity), and there is no apparent difference between student and community drinkers in the contribution of these two mechanisms.

The Impact of E-liquid Propylene Glycol and Vegetable Glycerin Ratio on Ratings of Subjective Effects, Reinforcement Value, and Use in Current Smokers

INTRODUCTION

Electronic nicotine delivery systems (ENDS) vary on a wide range of characteristics that may affect reinforcement value and use. One characteristic is the ratio of two solvents commonly used in most e-liquids: propylene glycol (PG) and vegetable glycerin (VG). The goal of this study was to understand how PG/VG ratio affects subjective effects, reinforcement value, and tobacco use patterns among current smokers who try using ENDS.

AIMS AND METHODS

Current smokers with minimal ENDS use history (n = 30) sampled, in a double-blind fashion, three different e-liquids that varied in PG/VG ratio (70/30, 50/50, 0/100) while holding constant other aspects of the e-liquid and ENDS. Participants tried each e-liquid before rating the subjective effects on a modified version of the Cigarette Evaluation Questionnaire. Reinforcement value was assessed using a preference task where participants chose between the three e-liquids. The impact of each e-liquid on cigarette reinforcement was assessed using a modified version of the Cigarette Purchase Task. Participants were randomly assigned to receive one e-liquid to take home for 1 week.

RESULTS

PG/VG ratio had minimal impact on most of the tested outcomes. Participants rated the highest PG concentration as having a stronger "throat hit" than the other two. There was no significant difference between the number of participants who preferred each of the PG/VG ratios in the preference assessment. PG/VG ratio did not affect cigarette or ENDS use during the sampling week.

CONCLUSIONS

These data suggest that PG/VG ratio has minimal impact on subjective effects and reinforcement value in ENDS naive current smokers.

IMPLICATIONS

These data suggest that PG/VG ratio, within the range that is commonly used, has minimal impact on subjective effects, reinforcement value, or uptake in current smokers with minimal ENDS experience.

More than Smoke and Patches: The Quest for Pharmacotherapies to Treat Tobacco Use Disorder

Tobacco use is a persistent public health issue. It kills up to half its users and is the cause of nearly 90% of all lung cancers. The main psychoactive component of tobacco is nicotine, primarily responsible for its abuse-related effects. Accordingly, most pharmacotherapies for smoking cessation target nicotinic acetylcholine receptors (nAChRs), nicotine's major site of action in the brain. The goal of the current review is twofold: first, to provide a brief overview of the most commonly used behavioral procedures for evaluating smoking cessation pharmacotherapies and an introduction to pharmacokinetic and pharmacodynamic properties of nicotine important for consideration in the development of new pharmacotherapies; and second, to discuss current and potential future pharmacological interventions aimed at decreasing tobacco use. Attention will focus on the potential for allosteric modulators of nAChRs to offer an improvement over currently approved pharmacotherapies. Additionally, given increasing public concern for the potential health consequences of using electronic nicotine delivery systems, which allow users to inhale aerosolized solutions as an alternative to smoking tobacco, an effort will be made throughout this review to address the implications of this relatively new form of nicotine delivery, specifically as it relates to smoking cessation. SIGNIFICANCE STATEMENT: Despite decades of research that have vastly improved our understanding of nicotine and its effects on the body, only a handful of pharmacotherapies have been successfully developed for use in smoking cessation. Thus, investigation of alternative pharmacological strategies for treating tobacco use disorder remains active; allosteric modulators of nicotinic acetylcholine receptors represent one class of compounds currently under development for this purpose.

Relative expected value of drugs versus competing rewards underpins vulnerability to and recovery from addiction

Behavioural economic theories of addiction contend that greater expected value of drug relative to alternative non-drug rewards is the core mechanism underpinning vulnerability to and recovery from addiction. To evaluate this claim, we exhaustively review studies with human drug users that have measured concurrent choice between drugs vs. alternative rewards, and explored individual differences. These studies show that drug choice can be modulated by drug cues, drug devaluation, imposition of costs/punishment and negative mood induction. Regarding individual differences, dependence severity was reliably associated with overall drug preference, and self-reported drug use to cope with negative affect was reliably associated with greater sensitivity to mood induced increases in drug choice. By contrast, there were no reliable individual differences in sensitivity to the effect of drug cues, drug devaluation or punishment on drug choice. These findings provide insight into the mechanisms that underpin vulnerability to dependence: vulnerability is conferred by greater relative value ascribed to drugs, and relative drug value is further augmented by negative affective states in those who report drug use coping motives. However, dependence does not appear to be characterised by abnormal cue-reactivity, habit learning or compulsion. We then briefly review emerging literature which demonstrates that therapeutic interventions and recovery from addiction might be attributed to changes in the expected relative value of drug versus alternative rewards. Finally, we outline a speculative computational account of the distortions in decision-making that precede action selection in addiction, and we explain how this account provides a blueprint for future research on the determinants of drug choice, and mechanisms of treatment and recovery from addiction. We conclude that a unified economic decision-making account of addiction has great promise in reconciling diverse addiction theories, and neuropsychological evaluation of the underlying decision mechanisms is a fruitful area for future research and treatment.

Addiction is driven by excessive goal-directed drug choice under negative affect: translational critique of habit and compulsion theory

Drug addiction may be a goal-directed choice driven by excessive drug value in negative affective states, a habit driven by strong stimulus-response associations, or a compulsion driven by insensitivity to costs imposed on drug seeking. Laboratory animal and human evidence for these three theories is evaluated. Excessive goal theory is supported by dependence severity being associated with greater drug choice/economic demand. Drug choice is demonstrably goal-directed (driven by the expected value of the drug) and can be augmented by stress/negative mood induction and withdrawal-effects amplified in those with psychiatric symptoms and drug use coping motives. Furthermore, psychiatric symptoms confer risk of dependence, and coping motives mediate this risk. Habit theory of addiction has weaker support. Habitual behaviour seen in drug-exposed animals often does not occur in complex decision scenarios, or where responding is rewarded, so habit is unlikely to explain most human addictive behaviour where these conditions apply. Furthermore, most human studies have not found greater propensity to habitual behaviour in drug users or as a function of dependence severity, and the minority that have can be explained by task disengagement producing impaired explicit contingency knowledge. Compulsion theory of addiction also has weak support. The persistence of punished drug seeking in animals is better explained by greater drug value (evinced by the association with economic demand) than by insensitivity to costs. Furthermore, human studies have provided weak evidence that propensity to discount cost imposed on drug seeking is associated with dependence severity. These data suggest that human addiction is primarily driven by excessive goal-directed drug choice under negative affect, and less by habit or compulsion. Addiction is pathological because negative states powerfully increase expected drug value acutely outweighing abstinence goals.

Behavioral economic demand and delay discounting are differentially associated with cigarette dependence and use in adolescents

INTRODUCTION

The Reinforcer Pathology Model describes how two behavioral economic processes, increased sensitivity to immediate rewards (delay discounting) and excessive reward derived from a substance (demand), both contribute to problematic patterns of substance use. In a novel application of this model, the current cross-sectional study examined how these distinct processes relate to different facets of cigarette use in adolescents.

METHODS

Adolescent daily cigarette smokers ages 15 to 19 (Mean age 17.7, N = 50) completed a laboratory assessment of demand using a Cigarette Purchase Task for their usual brand cigarettes and an adjusting-amount delay discounting task. Demand was conceptualized as two factors (Amplitude and Persistence) and delay discounting was calculated as Area Under the Curve (log AUC). The two factors of demand and discounting AUC were included as statistical predictors of level of cigarette dependence and average number of cigarettes smoked per day in linear regression models.

RESULTS

Amplitude of demand was marginally significant predictor (p = .06) of cigarettes smoked per day whereas neither Persistence of demand nor delay discounting significantly predicted this outcome. Both Amplitude of demand and delay discounting, but not Persistence, were associated with level of cigarette dependence. The effects of amplitude of demand and delay discounting on cigarette dependence or use did not significantly interact.

CONCLUSIONS

Results of this study suggest that amplitude of cigarette demand may be a risk factor for both cigarette consumption and dependence, while discounting - a known risk factor for cigarette initiation - may relate specifically to level of dependence.

Behavioral Economic Research in Addiction as an Area of Growth for the Experimental Analysis of Behavior

Behavioral economics, a synthesis of the experimental analysis of behavior (EAB) and economics, seeks to determine the relative value of reinforcers as a function of various environmental constraints. Early animal and human studies often focused on drug reinforcement, and this has continued to the present. In particular, behavioral economic analyses of human and animal behavior in relation to nicotine and cigarette smoking have contributed to a greater understanding of this behavior, and to a greater reliance on these methods in the field of smoking cessation treatment, tobacco regulatory science and tobacco control. In this commentary, we briefly describe the history of behavioral economics in the context of EAB methods, the particular contribution of these methods to understanding cigarette smoking and the advance of tobacco regulation, as well as opportunities for growth and remaining challenges in this area. As behavioral economics continues to stimulate research and inform policy, we propose that the underlying elements of a rigorous analytic approach to understanding behavior are key contributors to the fruitfulness of this approach.

Insights from Preclinical Choice Models on Treating Drug Addiction

Substance-use disorders are a global public health problem that arises from behavioral misallocation between drug use and more adaptive behaviors maintained by nondrug alternatives (e.g., food or money). Preclinical drug self-administration procedures that incorporate a concurrently available nondrug reinforcer (e.g., food) provide translationally relevant and distinct dependent measures of behavioral allocation (i.e., to assess the relative reinforcing efficacy of the drug) and behavioral rate (i.e., to assess motor competence). In particular, preclinical drug versus food 'choice' procedures have produced increasingly concordant results with both human laboratory drug self-administration studies and double-blind placebo-controlled clinical trials. Accordingly, here we provide a heuristic framework of substance-use disorders based on a behavioral-centric perspective and recent insights from these preclinical choice procedures.

Behavioral Economic Laboratory Research in Tobacco Regulatory Science

OBJECTIVES

Research that can provide a scientific foundation for the United States Food and Drug Administration (FDA) tobacco policy decisions is needed to inform tobacco regulatory policy. One factor that affects the impact of a tobacco product on public health is its intensity of use, which is determined, in part, by its abuse liability or reinforcing efficacy. Behavioral economic tasks have considerable utility for assessing the reinforcing efficacy of current and emerging tobacco products.

METHODS

This paper provides a narrative review of several behavioral economic laboratory tasks and identifies important applications to tobacco regulatory science.

RESULTS

Behavioral economic laboratory assessments, including operant self-administration, choice tasks and purchase tasks, can be used generate behavioral economic data on the effect of price and other constraints on tobacco product consumption. These tasks could provide an expedited simulation of the effects of various tobacco control policies across populations of interest to the FDA.

CONCLUSIONS

Tobacco regulatory research questions that can be addressed with behavioral economic tasks include assessments of the impact of product characteristics on product demand, assessments of the abuse liability of novel and potential modified risk tobacco products (MRTPs), and assessments of the impact of conventional and novel products in vulnerable populations.

Validation of a Respiratory Symptom Questionnaire in Adolescent Smokers

OBJECTIVES

Adolescent smokers experience respiratory symptoms as a consequence of smoking, which may be impacted by harm-reduction products. We sought to validate the American Thoracic Society Questionnaire (ATSQ), a measure of respiratory symptoms, in adolescent smokers.

METHODS

Data were drawn from 2 studies of adolescents (ages 14 to 19). Study 1 (N = 118) comprised daily smokers. Study 2 (N = 216) comprised 118 smokers and 98 nonsmokers; a subset of the total sample comprised 70 matched pairs of smokers and non-smokers.

RESULTS

The ATSQ showed high internal consistency. In Study 1, ATSQ scores were positively correlated with dependence. In Study 2, scores were positively correlated with CO, cotinine, and cigarettes per day; and scores were significantly greater for smokers than non-smokers.

CONCLUSIONS

The ATSQ offers a psychometrically valid method for measuring respiratory symptoms in adolescent smokers.