Rachel N. Cassidy

Single-Case Experimental Designs to Evaluate Novel Technology-Based Health Interventions

Technology-based interventions to promote health are expanding rapidly. Assessing the preliminary efficacy of these interventions can be achieved by employing single-case experiments (sometimes referred to as n-of-1 studies). Although single-case experiments are often misunderstood, they offer excellent solutions to address the challenges associated with testing new technology-based interventions. This paper provides an introduction to single-case techniques and highlights advances in developing and evaluating single-case experiments, which help ensure that treatment outcomes are reliable, replicable, and generalizable. These advances include quality control standards, heuristics to guide visual analysis of time-series data, effect size calculations, and statistical analyses. They also include experimental designs to isolate the active elements in a treatment package and to assess the mechanisms of behavior change. The paper concludes with a discussion of issues related to the generality of findings derived from single-case research and how generality can be established through replication and through analysis of behavioral mechanisms.

Reduced nicotine product standards for combustible tobacco: Building an empirical basis for effective regulation

INTRODUCTION Both the Tobacco Control Act in the U.S. and Article 9 of the Framework Convention on Tobacco Control enable governments to directly address the addictiveness of combustible tobacco by reducing nicotine through product standards. Although nicotine may have some harmful effects, the detrimental health effects of smoked tobacco are primarily due to non-nicotine constituents. Hence, the health effects of nicotine reduction would likely be determined by changes in behavior that result in changes in smoke exposure. METHODS Herein, we review the current evidence on nicotine reduction and discuss some of the challenges in establishing the empirical basis for regulatory decisions. RESULTS To date, research suggests that very low nicotine content cigarettes produce a desirable set of outcomes, including reduced exposure to nicotine, reduced smoking, and reduced dependence, without significant safety concerns. However, much is still unknown, including the effects of gradual versus abrupt changes in nicotine content, effects in vulnerable populations, and impact on youth. DISCUSSION A coordinated effort must be made to provide the best possible scientific basis for regulatory decisions. The outcome of this effort may provide the foundation for a novel approach to tobacco control that dramatically reduces the devastating health consequences of smoked tobacco.

The ABCs of incentive-based treatment in health care: a behavior analytic framework to inform research and practice.

Behavior plays an important role in health promotion. Exercise, smoking cessation, medication adherence, and other healthy behavior can help prevent, or even treat, some diseases. Consequently, interventions that promote healthy behavior have become increasingly common in health care settings. Many of these interventions award incentives contingent upon preventive health-related behavior. Incentive-based interventions vary considerably along several dimensions, including who is targeted in the intervention, which behavior is targeted, and what type of incentive is used. More research on the quantitative and qualitative features of many of these variables is still needed to inform treatment. However, extensive literature on basic and applied behavior analytic research is currently available to help guide the study and practice of incentive-based treatment in health care. In this integrated review, we discuss how behavior analytic research and theory can help treatment providers design and implement incentive-based interventions that promote healthy behavior.

Concurrent performance in a three-alternative choice situation: Response allocation in a Rock/Paper/Scissors game ☆

Adult human subjects engaged in a simulated Rock/Paper/Scissors game against a computer opponent. The computer opponents responses were determined by programmed probabilities that differed across 10 blocks of 100 trials each. Response allocation in Experiment 1 was well described by a modified version of the generalized matching equation, with undermatching observed in all subjects. To assess the effects of instructions on response allocation, accurate probability-related information on how the computer was programmed to respond was provided to subjects in Experiment 2. Five of 6 subjects played the counter response of the computers dominant programmed response near-exclusively (e.g., subjects played paper almost exclusively if the probability of rock was high), resulting in minor overmatching, and higher reinforcement rates relative to Experiment 1. On the whole, the study shows that the generalized matching law provides a good description of complex human choice in a gaming context, and illustrates a promising set of laboratory methods and analytic techniques that capture important features of human choice outside the laboratory.

Smoking Topography Characteristics of Very Low Nicotine Content Cigarettes, With and Without Nicotine Replacement, in Smokers With Schizophrenia and Controls

INTRODUCTION Reducing the nicotine content of cigarettes to a minimally addictive level has been proposed as a regulatory strategy for reducing tobacco dependence. However, smokers with schizophrenia (SS) may be prone to changing their smoking topography in efforts to compensate for the reduction in nicotine content. The aims of this study were to compare smoking topography characteristics of usual-brand and very low nicotine content (VLNC) cigarettes in SS and control smokers without psychiatric illness (CS), and to determine whether nicotine replacement reversed any changes in topography produced by VLNC cigarettes. METHODS Using a within-subjects, counter-balanced design, SS (n = 27) and CS (n = 23) smoked usual brand cigarettes, VLNC cigarettes while wearing placebo patches (VLNC + PLA), or VLNC cigarettes while wearing transdermal nicotine patches totaling 42mg (VLNC + NIC) during 5-hour ad libitum smoking sessions. Cigarettes were smoked through topography measurement devices. RESULTS Across conditions, SS smoked more puffs per session and per cigarette, had higher cigarette volumes, and had shorter inter-puff intervals than CS (Ps < .01). During VLNC cigarette sessions, puff duration increased and time between puffs decreased, but participants smoked fewer puffs, resulting in a net decrease in cigarette and total session volume (Ps < .001). There were no significant interactions between group and condition. CONCLUSIONS These findings indicate that acute use of VLNC cigarettes does not increase intensity of smoking in SS, and support the feasibility of a nicotine reduction policy. IMPLICATIONS Reducing the nicotine in cigarettes to a minimally addictive level has been proposed as a means of reducing tobacco dependence. However, smokers, particularly those with schizophrenia (SS) may alter their puffing in an attempt to extract more nicotine from VLNC cigarettes. This study compared smoking topography of usual brand versus VLNC cigarettes, combined with placebo or transdermal nicotine patches, in SS and controls. Although some changes in topography were indicative of compensatory smoking, total puffs and total cigarette volume were reduced with VLNC cigarettes, indicating that acute VLNC cigarette use does not increase smoking in SS.

Barriers to Quitting Smoking Among Substance Dependent Patients Predict Smoking Cessation Treatment Outcome

For smokers with substance use disorders (SUD), perceived barriers to quitting smoking include concerns unique to effects on sobriety as well as usual concerns. We expanded our Barriers to Quitting Smoking in Substance Abuse Treatment (BQS-SAT) scale, added importance ratings, validated it, and then used the importance scores to predict smoking treatment response in smokers with substance use disorders (SUD) undergoing smoking treatment in residential treatment programs in two studies (n=184 and 340). Both components (general barriers, weight concerns) were replicated with excellent internal consistency reliability. Construct validity was supported by significant correlations with pretreatment nicotine dependence, smoking variables, smoking self-efficacy, and expected effects of smoking. General barriers significantly predicted 1-month smoking abstinence, frequency and heaviness, and 3-month smoking frequency; weight concerns predicted 1-month smoking frequency. Implications involve addressing barriers with corrective information in smoking treatment for smokers with SUD.

Quantifying nicotine's value-enhancement effect using a behavioral economic approach.

Nicotine increases the value of some reinforcing stimuli, and this effect may contribute to nicotines widespread abuse. We aimed to quantify this effect using a behavioral economic analysis. Six Long- Evans rats were exposed to a modified observing response procedure. In this procedure, presses to one lever resulted either in food according to a variable-interval 15 s schedule or extinction; presses to a second, observing lever illuminated stimuli correlated with the schedule in effect on the food/extinction lever (i.e., conditioned reinforcers). The FR requirement on the observing lever increased across sessions. The number of presentations of the conditioned reinforcers was plotted as a function of FR value to generate a demand curve. Nicotine was then administered at a dose of 0.3 mg/kg. All demand curves were fitted to the exponential demand equation and a parameter reflecting reinforcer value was evaluated. Nicotine increased the value of the conditioned reinforcers as measured by this equation; nicotine also increased responding on the food/extinction lever. This analysis demonstrates that nicotine increases the value of conditioned reinforcers under certain conditions. The current procedure allows for a novel method of analyzing demand for conditioned reinforcers.

Adolescent smokers’ response to reducing the nicotine content of cigarettes: Acute effects on withdrawal symptoms and subjective evaluations

BACKGROUND Mandating a reduction in the nicotine content of cigarettes to a minimally addictive level could dramatically reduce smoking rates in the US. However, little is known about the effects of reduced nicotine content cigarettes in adolescents. METHODS Following overnight abstinence, adolescent daily smokers (ages 15-19, n = 50) reported on their craving, withdrawal, and positive and negative affect pre- and post- ad lib smoking of one cigarette containing varying nicotine content (15.8, 5.2, 1.3 and 0.4 mg/g of tobacco) in the laboratory and reported their subjective evaluations of each cigarette. Carbon monoxide (CO) boost from pre- to post-cigarette was calculated to determine if lower-nicotine cigarettes led to differential acute changes in toxicant exposure. RESULTS All four nicotine cigarette types significantly reduced abstinence-induced craving, withdrawal, and negative affect (all ps < .05). Mixed models evaluating the effect of nicotine content, with nicotine dependence level and gender included as covariates, revealed a significant effect of nicotine content on craving and subjective evaluations: higher nicotine content resulted in greater reductions in craving and increases in both positive and negative subjective evaluations. There were no significant effects of nicotine dose on withdrawal symptoms, negative affect, or CO boost. CONCLUSIONS These results suggest that lower nicotine cigarettes might result in reduced abuse liability compared to higher nicotine content cigarettes due to reduced positive subjective effects, while still reducing withdrawal, in adolescents. These results highlight the potential feasibility of this policy approach and support continued research on how a nicotine reduction policy may affect adolescent smoking patterns.

Initial Development of an E-cigarette Purchase Task: A Mixed Methods Study

OBJECTIVES Behavioral economic purchase tasks, which estimate demand for drugs, have been successfully developed for cigarettes and are widely used. However, a validated purchase task does not yet exist for e-cigarettes. The aim of this project was to identify the relevant units for an e-cigarette purchase task (E-CPT). METHODS Focus groups (N=28 participants in 7 groups, 2-7 participants per group) consisting of current e-cigarette users were conducted. Participants discussed their daily use patterns, completed a preliminary E-CPT which asked how many puffs of their e-cigarette they would consume per day at escalating prices, and discussed the extent to which the task accurately reflected their real-world behavior. Groups were recorded and transcribed; analysis focused on statements related to daily consumption and the E-CPT. RESULTS Participants were unlikely to quantify their daily use in terms of puffs, and perceptions about the appropriate unit for an E-CPT varied across device type. Users of first-generation devices (eg, cigalikes) reported that the relevant unit was the individual device/cartridge; however, participants who purchased nicotine liquid for their device emphasized that e-liquid volume in milliliters would better reflect their use. CONCLUSIONS Multiple versions of the E-CPT may be necessary to provide valid measures of e-cigarette demand.

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.