Working Memory Training on Delay Discounting Among Cigarette Smokers

Study Overview
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Brief Summary
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Despite widespread awareness of significant negative health consequences, cigarette smoking remains the leading cause of preventable morbidity and mortality in the US (Creamer et al., 2019; Jamal, 2018). Moreover, the highest rate of smoking and heaviest burden of smoking-related illness occurs among low-socioeconomic status (SES) individuals relative to higher SES groups (Businelle et al., 2010; Clegg et al., 2009). Low SES individuals are also 40% less likely to succeed in quitting smoking when they attempt to do so (National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health, 2014). One potential explanation for the disparity in rate of smoking and successful quit attempts may be differences in individual rates of delay discounting (DD), i.e., the degree to which rewards loses their value as the delays to their receipt increase (Odum, 2011). A proposed way to reduce steep DD and, potentially, substance use has been computer training for working memory, which has shown favorable results in a sample of individuals with stimulant dependence (Bickel et al., 2011) and substance use broadly (Felton et al., 2019), with the latter even showing decreases in cigarette smoking in a subset of the sample.

Detailed Description
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The highest rate of smoking and heaviest burden of smoking-related illness occurs among low-SES individuals (Businelle et al., 2010; Clegg et al., 2009). One explanation for this disparity may be differences in individual rates of DD, which have been showed to be reduced with working memory training. (Bickel et al., 2011; Felton et al., 2019). Given the low cost of administering working memory training, such an intervention may be favorable for low-SES populations to improve smoking cessation outcomes. DD has significant associations with: Cigarette smoking (smokers tend to have higher rates of DD compared to non-smokers; Bickel et al., 1999); Smoking treatment outcome (individuals who remained smoke free after a smoking cessation intervention had lower DD compared to those who didn't; González-Roz et al., 2019; Krishnan-Sarin et al., 2007; MacKillop & Kahler, 2009; Yoon et al., 2007); SES (individuals with lower education and income have higher DD rates compared to those who are more educated and affluent; de Wit et al., 2007; Reimers et al., 2009). An innovative way to reduce DD that has been proposed is via working memory (WM) training. WM refers to one's capacity to hold information while engaging in complex mental tasks, including reasoning, comprehension, and learning (Baddeley, 2010). Previous research has shown that DD and WM correlate negatively (Shamosh et al., 2008), that individuals with higher DD rates show neural deficits in WM (Herting et al., 2010), and that acute nicotine abstinence is associated with WM deficits (Mendrek et al., 2006; Patterson et al., 2010). Furthermore, previous studies targeting WM to reduce DD have shown favorable results in a sample of individuals with stimulant dependence (Bickel et al., 2011) and substance use broadly (Felton et al., 2019), with the latter even showing decreases in cigarette smoking in a subset of the sample. Although previous research has shown WM training to reduce DD (which would support H3), and cigarette use in a small subsample, the hypotheses of this study are largely exploratory. However, given the theoretical connections between DD, SES, and WM, it is expected that the hypotheses of this project will be supported. The performance of this project may advance our knowledge of the relevant clinical targets for smoking cessation in low-SES individuals. In particular, this project is expected to shed light on DD as the putative mechanism in smoking for low-SES individuals and the durability of reductions in smoking as a result of reductions in DD through WM training. Despite the evidence for some successful techniques for reducing DD, little of this work has been translated into intervention approaches to target clinical outcomes. This application seeks to capitalize on the emerging literatures indicating (1) WM training may be an effective and efficient way to reduce DD, and (2) DD is associated with SES, cigarette smoking, and treatment outcomes. Though WM training has been successfully implemented in laboratory-controlled experiments to reduce DD, we are not aware of any interventions for clinical disorders that specifically seek to do so and potentially enhance treatment outcomes. The development of effective, theoretically coherent interventions addressing cigarette smoking is imperative, particularly interventions that would be feasible, efficacious, and acceptable in low-SES individuals. The proposed research is an innovative approach that capitalizes on previous findings showing reductions in delay discounting and even cigarette smoking. If working memory training is found to improve smoking cessation outcomes as a function of reductions in delay discounting, the project results could be helpful in future development of low-cost interventions for cigarette smoking.

Official Title
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Remember to Abstain: Assessment of Working Memory Training on Delay Discounting in Low-SES Cigarette Smokers

Conditions
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Tobacco Use Disorder/Cigarette Smoking

Intervention / Treatment
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* Behavioral: Working Memory Training (Active Intervention) + Behavioral Intervention
* Behavioral: Control Training (CT) + Behavioral Intervention


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: To be included in this study, a participant must be 18 years of age or older, who have smoked at least four cigarettes per day for at least 6 months, are interested in quitting cigarette smoking, are at or below the federal poverty line based on persons in family/household and annual household income: 1 -- $12,880 2 -- $17,420 3 -- $21,960 4 - $26,500 5 -- $31,040 6 -- $35,580 7 -- $40,120 8 -- $44,660 9 - add $4,540 for each additional person, OR they or their child(ren) utilize a federal program for low-income individuals, and are willing to participate in a 5-week working memory training program as a pretreatment adjunct to behavioral group + nicotine replacement therapy (NRT; via nicotine patches). Exclusion criteria: Participants must not indicate a severe substance use disorder according to the DSM-V with any substance other than tobacco or have any significant medical or psychiatric condition. Such conditions could include traumatic brain injury, dementia, significant learning disability, or psychotic symptoms. Participants must be at least at a 5th-grade reading level. In case that participants are excluded, they will be provided with resources in the community and provided with contact information for the Kansas Tobacco Quitline.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants will be randomized to the Computerized Working Memory Training or the Computerized Control Condition
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Working Memory Training (Active Training) + Behavioral Intervention<br>Participants will be randomized to complete 10 sessions of a Working Memory Training. All participants will receive behavioral activation (a behavioral intervention for smoking cessation) and nicotine patches. | Behavioral: Working Memory Training (Active Intervention) + Behavioral Intervention<br>* Participants will be randomized to complete 10 sessions of a Working Memory Training. All participants will receive behavioral activation (a behavioral intervention for smoking cessation) and nicotine patches.<br>|
| Active Comparator: Control Training (CT) + Behavioral Intervention<br>Participants will be randomized to complete 10 sessions of a Control Condition Memory Training. All participants will receive behavioral activation (a behavioral intervention for smoking cessation) and nicotine patches. | Behavioral: Control Training (CT) + Behavioral Intervention<br>* Participants will be randomized to complete 10 sessions of a Control Condition Memory Training. All participants will receive behavioral activation (a behavioral intervention for smoking cessation) and nicotine patches.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Delay Discounting | A computerized binary choice task in which participants choose between an amount of money available immediately and larger amount of money available after a specified delay (1 day, 1 week, 1 month, 6 months, 1 year, 5 years, 25 years). | Baseline, Post-treatment, 1 month follow up | 
| Timeline Follow-Back | The Timeline Follow-up will be used to measure point prevalence of tobacco smoking. | Pre-training, post-training, 1 week post-quit date, one-month post-quit date | 
| Carbon Monoxide Levels | Participant reports of abstinence will be verified by expired carbon monoxide (< 6 ppm cutoff for stated abstinence). | Baseline, Post-treatment, 1- week post quit date session, 1 month follow up | 
| Working Memory | A working memory index will be created using three different working memory measure: 1) the total achievement score in the Tower of Hanoi (TOH), 2) the total recall score of the Hopkins Verbal Learning Test- Revised (HVLT-R) and 3) the total scaled score of the Letter Number Sequencing (LNS). | Baseline, Post-treatment, 1 month follow up |