Effects of 6-month episodic future thinking training on delay discounting, weight loss and HbA1c changes in individuals with prediabetes

Mediating Role of Delay Discounting in the Link Between Depressive Symptoms and Diabetes Onset: Findings from a Prospective Survey of a Community Sample

BACKGROUND

The positive relationship between higher delay discounting, an indicator of increased impulsivity, and reduced engagement in diabetes care has been investigated. However, the association between delay discounting and diabetes onset, likely linked through unhealthy behaviors, has not been well investigated. Additionally, although depression has been linked to an increased risk of diabetes and greater delay discounting, studies examining associations among all three factors are scarce. The present study aimed to determine the association between depressive symptoms and the onset of diabetes, with delay discounting as a mediator of this relationship.

METHODS

Using data from a three-phase online prospective survey of a community sample, cross-sectional and longitudinal mediation analyses were conducted to examine diabetes prevalence from Phase 1 and incidence from Phases 2 and 3 as the outcomes, with depressive symptoms at Phase 1 as the independent variable and delay discounting at Phase 1 as the mediator.

RESULTS

Delay discounting was positively associated both with diabetes prevalence (coefficient = 0.170; 95% confidence interval [CI] = 0.066 to 0.278; P = 0.002) and incidence (coefficient = 0.306; 95% CI = 0.098 to 0.540; P = 0.006). Furthermore, through delay discounting, depressive symptoms were indirectly associated with diabetes prevalence (indirect coefficient = 0.091; 95% bootstrap CI = 0.034 to 0.149) and incidence (indirect coefficient = 0.138; 95% bootstrap CI = 0.037 to 0.256), respectively.

CONCLUSIONS

Delay discounting may increase the risk of diabetes onset by mediating the positive association between depressive symptoms and diabetes onset.

Relationship Between Delay Discounting and Clinical Diabetes Outcomes: A Systematic Review

OBJECTIVE

To evaluate the evidence on the relationship between delay discounting and clinical diabetes outcomes, identify current measures, and recommend areas for future work.

METHODS

A reproducible search using OVID Medline, PsycINFO, PubMed, Science Direct, and Scopus was conducted. Articles published from database creation up to March 2024 were searched. Medical Subject Heading (MeSH) terms and keywords representing delay discounting and diabetes were used. Outcomes included hemoglobin A1c (HbA1c), LDL, body mass index (BMI), blood pressure, quality of life (QOL), psychosocial factors, self-care behaviors, and diabetes complications.

RESULTS

A total of 15 articles met the inclusion criteria and were included for final synthesis. Overall, 14 studies included in this review found a significant relationship between delay discounting and diabetes-related outcomes, such that higher delay discounting is significantly related to worse diabetes outcomes for HbA1c, self-care behaviors, BMI, stress, and quality of life across self-reported measures of delay discounting and delay discounting tasks.

CONCLUSIONS

Evidence supports the relationship between delay discounting and diabetes-related outcomes and self-care behaviors across measures of delay discounting and type of diabetes. To understand delay discounting as a mechanism driving diabetes outcomes and to develop targeted interventions, additional work using a multidisciplinary approach is needed to validate the construct, identify pathways, and refine intervention approaches that can be tested to improve population health.

Differential signaling effects of blood glucose on delay discounting in individuals with and without type 1 diabetes

Based on the signaling hypothesis of blood glucose (BG), a rise in BG levels signals a positive energy budget for healthy individuals but cellular starvation for individuals with type 1 diabetes. We examined this novel prediction and its intervention implications in the context of delay discounting, the degree to which delayed rewards are discounted, and the regulatory effects of insulin ingestion. We recruited 44 adults with type 1 diabetes (mean age 30.8 years, diabetes duration 15.4 years) and recorded their BG levels. The delay discounting rate was measured using the intertemporal choice task, where participants were required to choose between sets of smaller-and-sooner (SS) and larger-and-later (LL) rewards. In addition, 82 age-matched healthy participants were recruited to provide a baseline comparison on delay discounting. Random forest analysis showed that among many diagnostic factors, delay discounting was most dominating in differentiating the individuals with type 1 diabetes from the control participants. A hierarchical linear mixed model revealed that participants with type 1 diabetes had a stronger preference for SS rewards (p < .001) after controlling for covariates. Participants who had insulin delivered before the last meal exhibited a stronger preference for LL rewards compared to after-meal delivery. In contrast, subjective measures (e.g., self-reported hunger) failed to predict the participants' actual BG levels and delay discounting rates. In sum, individuals with type 1 diabetes tend to discount future rewards excessively compared to the control participants. Pre-meal insulin ingestion was associated with a higher LL preference for future rewards.

A psychobioecological model to understand the income-food insecurity-obesity relationship

Food insecurity, defined by unpredictable access to food that may not meet a person's nutritional needs, is associated with higher BMI (kg/m2) and obesity. People with food insecurity often have less access to food, miss meals and go hungry, which can lead to psychological and metabolic changes that favor energy conservation and weight gain. We describe a conceptual model that includes psychological (food reinforcement and delay discounting) and physiological (thermic effect of food and substrate oxidation) factors to understand how resource scarcity associated with food insecurity evolves into the food insecurity-obesity paradox. We present both animal and human translational research to describe how behavioral and metabolic adaptations to resource scarcity based on behavioral ecology theory may occur for people with food insecurity. We conclude with ideas for interventions to prevent or modify the behaviors and underlying physiology that characterize the income-food insecurity-obesity relationship.

Examining the association between delay discounting, delay aversion and physical activity in Chinese adults with type-2 diabetes mellitus

BACKGROUND

The role of physical activity in diabetes is critical, influencing this disease's development, man-agement, and overall outcomes. In China, 22.3% of adults do not meet the minimum level of physical activity recommended by the World Health Organization. Therefore, it is imperative to identify the factors that contributing to lack of physical activity must be identified.

AIM

To investigate the relationship among delay discounting, delay aversion, glycated hemoglobin (HbA1c), and various levels of physical activity in Chinese adults diagnosed with type 2 diabetes mellitus (T2DM).

METHODS

In 2023, 400 adults with T2DM were recruited from the People's Hospital of Linxia Hui Autonomous Prefecture of Gansu Province. A face-to-face questionnaire was used to gather demographic data and details on physical activity, delay discounting, and delay aversion. In addition, HbA1c levels were measured in all 400 participants. The primary independent variables considered were delay discounting and delay aversion. The outcome variables included HbA1c levels and different intensity levels of physical activity, including walking, moderate physical activity, and vigorous physical activity. Multiple linear regression models were utilized to assess the relationship between delay discounting, delay aversion, and HbA1c levels, along with the intensity of different physical activity measured in met-hours per week.

RESULTS

After controlling for the sample characteristics, delay discounting was negatively associated with moderate physical activity (β = -2.386, 95%CI: -4.370 to -0.401). Meanwhile, delay aversion was negatively associated with the level of moderate physical activity (β = -3.527, 95% CI: -5.578 to -1.476) in the multiple linear regression model, with statistically significant differences.

CONCLUSION

Elevated delay discounting and increased delay aversion correlated with reduced levels of moderate physical activity. Result suggests that delay discounting and aversion may influence engagement in moderate physical activity. This study recommends that health administration and government consider delay discounting and delay aversion when formulating behavioral intervention strategies and treatment guidelines involving physical activity for patients with T2DM, which may increase participation in physical activity. This study contributes a novel perspective to the research on physical activity in adults with T2DM by examining the significance of future health considerations and the role of emotional responses to delays.

Effects of episodic future thinking in health behaviors for weight loss: A systematic review and meta-analysis

BACKGROUND

Obesity and related diseases have become one of the leading causes of death worldwide, which has been linked to biopsychosocial effects such as type 2 diabetes, cardiovascular disease, various cancers, depression, and weight stigma. Episodic future thinking (EFT) has been found to support the development of changes in health behaviors. However, the effectiveness of EFT in enhancing weight loss behavior and health outcomes is not well supported.

OBJECTIVE

To establish implementation options for the EFT intervention, and critically synthesize the data that assesses the impact of EFT on weight loss behavior and health outcomes.

METHODS

Searches were performed across 5 Chinese and 9 English databases systematically from inception to March 2023. Randomized controlled trials, written in English or Chinese were included. Two independent reviewers evaluated all relevant studies, who also assessed the risk of bias, and extracted the data. Meta-analyses were conducted using Review Manager 5.4.1. The quantity of evidence's certainty was assessed using the Risk bias assessment tool RoB2 (revised version 2019). This study was registered in PROSPERO.

RESULTS

A total of 1740 participants were included, and 18 studies were eligible for inclusion. Meta-analysis reported a statistically significant effect size favoring EFT on delay discounting (AUC) (MD = 0.1, 95 % CI: [0.02, 0.17], P = 0.01; I2 = 73 %), delay discounting (K) (MD = -0.85, 95 % CI: [-1.44, -0.26], P = 0.005; I2 = 77 %), energy intake (MD = -107.59, 95 % CI: [-192.21, -22.97], P = 0.01; I2 = 57 %), grocery purchased (SMD: -0.91, 95 % CI:[-1.48, -0.34], P = 0.002; I2 = 63 %), and BMI (MD = -2.73, 95 % CI: [-5.13, -0.32], P = 0.03; I2 = 0 %, two studies).

CONCLUSIONS

EFT was found to have favorable effects on delay discounting, energy intake, grocery purchased, and BMI of individuals. The presence of high heterogeneity is evident in most of the outcomes. The modalities of EFT intervention are still in the exploratory phase, there is no consensus on the valence, context type, longest delay time, and practice strategy, and it needs to be further explored for different populations. It is anticipated that additional well-designed studies will continue developing high-quality evidence in this field.

Art-delivered episodic future thinking reduces delay discounting: A phase IIa proof-of-concept trial

INTRODUCTION

High rates of delay discounting (DD), or the preference for immediate rewards over delayed rewards, is associated with substance use disorder (SUD). Lower rates of DD predict better treatment outcomes, and thus strategies that reduce DD may support SUD recovery. The process of vividly imagining a future event, known as episodic future thinking (EFT), may be a particularly viable approach to reduce DD. Some limited research has examined delivery of EFT in treatment settings, using verbal prompts that are typical of studies in non-treatment settings. We propose that the creation of visual art represents a unique alignment of the purpose of EFT with an innovative delivery modality in treatment settings.

METHODS

This single arm, proof-of-concept trial evaluated art-delivered EFT (ArtEFT) to reduce DD in a sample of women (N = 39) in a residential SUD treatment center. Participants engaged in a single, 1-h ArtEFT session during which they engaged in EFT and created a visual representation using art materials. The study collected DD measures for hypothetical money ($50 and $1000 magnitude conditions) before and after ArtEFT.

RESULTS

Using area-under-the-curve (AUCord) as the index of DD, the study observed predicted changes following the ArtEFT session. The ANOVA revealed statistically significant main effects of both magnitude [F(1,38) = 11.184, p = .002] and time [F(1. 38) = 4.731, p = .036], with a non-significant interaction [F(1,38) = 3.821, p = .058].

CONCLUSION

This study reveals promising preliminary indicators that art may be an effective modality to deliver EFT, with particular advantages for implementation given the popularity of art programming in SUD treatment programs.

Glucose response to sugar challenge moderates the effect of insulin resistance on reinforcing value of sugar-sweetened yogurt

We have shown insulin resistance is associated with the choice of sugar-sweetened over monk fruit sweetened yogurt. This study extends this research by assessing the association between insulin resistance and reinforcing value for sugar versus monk fruit-sweetened yogurt, and testing the hypothesis that this effect is moderated by greater blood glucose response in people with insulin resistance. Eighteen people with overweight/obesity (BMI = 35.8 kg/m2, range 26.2-48.5) with varying degrees of insulin resistance (Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) = 2.6, range of 0.6-8.0) had blood glucose measured for 2 h after a sugar challenge. Over six days, they consumed, in a double-blind fashion, novel flavored-colored sugar or monk fruit-sweetened yogurts, and the reinforcing value of sugar or monk fruit-sweetened yogurts and delay discounting (DD) were measured. HOMA-IR (r = 0.62, p = .006) and insulin (r = 0.51, p = .03) were related to the reinforcing value of sugar-sweetened, but not monk fruit-sweetened yogurt (r = -0.07, -0.10, respectively). The blood glucose area under the curve moderated the relationship between HOMA-IR and the reinforcing value of sugar-sweetened yogurt (p = .02). People with greater HOMA-IR and greater blood glucose excursions responded the most for sugar-sweetened yogurt. These results extend previous research and confirm the hypothesis that individual differences in response to sugar may activate brain reward centers and condition people to prefer high-sugar foods. DD was related to sugar reinforcement (r = -0.46, p = .03), consistent with the idea that those with high sugar reinforcement desire immediate gratification, and DD moderated the relationship between HOMA-IR and the reinforcing value of sugar-sweetened yogurt (p < .001). Research should test whether reducing insulin resistance would permit people with insulin resistance to choose lower-sugar foods.

Perceptions and effectiveness of episodic future thinking as digital micro-interventions based on mobile health technology

Objective

Delay discounting denotes the tendency for humans to favor short-term immediate benefits over long-term future benefits. Episodic future thinking (EFT) is an intervention that addresses this tendency by having a person mentally "pre-experience" a future event to increase the perceived value of future benefits. This study explores the feasibility of using mobile health (mHealth) technology to deliver EFT micro-interventions. Micro-interventions are small, focused interventions aiming to achieve goals while matching users' often limited willingness or capacity to engage with interventions. We aim to explore whether EFT delivered as digital micro-interventions can reduce delay discounting, the users' perceptions, and if there are differences between regular EFT and goal-oriented EFT (gEFT), a variant where goals are embedded into future events.

Method

A randomized study was conducted with 208 participants allocated to either gEFT, EFT, or a control group for a 21-day study.

Results

Results indicate intervention groups when combined achieved a significant reduction of Δ log k = - .80 in delay discounting (p = .017 ) compared to the control. When split into gEFT and EFT separately only the reduction of Δ log k = .96 in EFT delay discounting was significant (p = .045 ). We further explore and discuss thematic user perceptions.

Conclusions

Overall, user perceptions indicate gEFT may be slightly better for use in micro-interventions. However, perceptions also indicate that audio-based EFT micro-interventions were not always preferable to users, with findings suggesting that future EFT micro-interventions should be delivered using different forms of multimedia based on user preference and context and supported by other micro-interventions to maintain interest.

Parents, but not their children, demonstrate greater delay discounting with resource scarcity

BACKGROUND

Individuals with obesity tend to discount the future (delay discounting), focusing on immediate gratification. Delay discounting is reliably related to indicators of economic scarcity (i.e., insufficient resources), including lower income and decreased educational attainment in adults. It is unclear whether the impact of these factors experienced by parents also influence child delay discounting between the ages of 8 and 12-years in families with obesity.

METHODS

The relationship between indices of family income and delay discounting was studied in 452 families with parents and 6-12-year-old children with obesity. Differences in the relationships between parent economic, educational and Medicaid status, and parent and child delay discounting were tested.

RESULTS

Results showed lower parent income (p = 0.019) and Medicaid status (p = 0.021) were differentially related to greater parent but not child delay discounting among systematic responders.

CONCLUSIONS

These data suggest differences in how indicators of scarcity influence delay discounting for parents and children, indicating that adults with scarce resources may be shaped to focus on immediate needs instead of long-term goals. It is possible that parents can reduce the impact of economic scarcity on their children during preadolescent years. These findings suggest a need for policy change to alleviate the burden of scarce conditions and intervention to modify delay discounting rate and to improve health-related choices and to address weight disparities.

Delay Discounting and the Income-Food Insecurity-Obesity Paradox in Mothers

Food insecurity, defined as unpredictable access to food that may not meet a person's nutritional needs, is paradoxically associated with higher BMI (kg/m2) and obesity. Research has shown delay discounting, a behavioral economic measure of the preference for immediate rather than delayed rewards, is related to higher BMI, and moderates the relationship between income and food insecurity. Based on this research, we used regression models to test whether delay discounting, consideration of future consequences, and perceived stress were atemporal mediators of the food insecurity-BMI relation in 313 mothers, controlling for demographic variables. A secondary aim was to replicate the finding that delay discounting moderates the relationship between low income and high food insecurity. Results showed that low income was associated with higher food insecurity, and higher food insecurity was associated with higher BMI. Delay discounting was the only variable that was indirectly related to both paths of the food-insecurity-BMI relation. Delay discounting accounted for 22.2% of the variance in the low-income-food insecurity-obesity relation, and the total model accounted for 38.0% of the variance. The relation between low income and food insecurity was moderated by delay discounting. These data suggest that delay discounting is a potential mediator of the relationship between food insecurity and high BMI, which suggests reducing discounting in the future could be a novel target to reduce food insecurity and help people with food insecurity to reduce their excess body weight. Trial Registration. This trial is registered with NCT02873715.

The use of episodic future thinking in people with overweight or obesity: A scoping review

A growing number of studies have applied Episodic Future Thinking (EFT) to cognitive interventions in specific population. However, The variability in study populations may lead to inconsistent results and present challenges in the optimal intervention approach and scope of adaptation. This scoping review aimed to identify and describe specific methods, considerations, and results collected and reported in randomized controlled trials of EFT applied to diet and weight management in people with overweight or obesity. A systematic scoping review was conducted by published guidelines for this review. We conducted a structured search of English-language articles in Web of Science, PubMed, Embase, CINAHL, ProQuest, and Cochrane, with the literature focusing on studies published up to December 28, 2022. After screening and full-text review, 16 studies were included. The studies included people of all ages with overweight or obesity, including women, children, and home-based EFT interventions. The vast majority of intervention studies screened participants for psychological characteristics, and the effects of EFT applied in people with overweight or obesity were somewhat significant, although there was some variation in the literature. Although the individual heterogeneity of studies makes the synthesis of results somewhat variable, it still demonstrates the breadth and accessibility of EFT interventions in people with overweight or obesity. The application of EFT to individualized interventions in people with overweight or obesity is a further complement and optimization of weight management through behavioral cognitive therapy.

How is Patient Adherence Possible? A Novel Mechanistic Model of Adherence Based on Humanities

Patient non-adherence is a major contemporary medical issue because of its consequences in terms of frequency, morbidity and mortality, and health care costs. This article aims to propose a mechanistic model of adherence based on the tenet that non-adherence is the default option, as long-term adherence in chronic diseases requires sustained effort. The real question becomes, how is patient adherence possible? By focusing on adherent patients, the paper explains the mental mechanisms of adherence using concepts largely drawn from humanities, philosophy of mind, and behavioral economics and presents the findings of empirical studies supporting these hypotheses. The analysis first demonstrates the relationship between patient adherence and temporality and the influence of character traits. Further, it points out the importance of habit, which allows adherence to become non-intentional, thereby sparing patients' cognitive efforts. Finally, it points out the importance of the quality of the interaction between the person with a chronic disease and the health professional. These features explain why adherence is a syndrome (the healthy adherer phenotype), separating people into those who are safe and those who are at risk of non-adherence, non-control of diabetes, and complications. The concepts presented in this article summarize 20 years of personal clinical and philosophical reflection on patient adherence. They are mainly illustrated by examples from diabetes care but can be applied to all chronic diseases. This novel model of adherence has major practical and ethical implications, explaining the importance of patient education and shared medical decision-making in chronic disease management.

Disrupting future discounting: a commentary on an underutilised psychological approach for improving adherence to diet and physical activity interventions

Non-communicable diseases (NCD) such as CVD and type 2 diabetes mellitus are major contributors to the burden of disease. NCD are largely driven by modifiable lifestyle factors including poor diet and insufficient physical activity, and consequently, prevention is a public health priority. Although diet and physical activity levels can be improved via lifestyle interventions, long-term adherence to such interventions remains low, which limits their effectiveness. Thus, it is critical to identify the underlying mechanisms that challenge uptake and adherence to such interventions. The current commentary discusses an important, but underexplored, psychological driver of poor adherence to lifestyle interventions, namely, future discounting, which describes the tendency to prefer smaller, short-term rewards over larger, long-term rewards. For example, in the nutrition domain, future discounting refers to valuing the immediate reward of excessive intake of energy-dense, nutrient-poor, discretionary foods high in salt, sugar, and saturated fat, and insufficient intake of low-energy, nutrient-dense, whole foods such as vegetables. Prominent theoretical models propose that excessive future discounting is a major contributor to the development of unhealthy lifestyle behaviours. Furthermore, a vast body of evidence suggests that future discounting plays a key role in risk of NCD. Thus, the evidence to date supports the idea that future discounting is an important multi-behaviour target for supporting lifestyle behaviour change; however, this approach has been largely neglected in preventive health efforts. Furthermore, this commentary discusses promising techniques (e.g. Episodic Future Thinking) for disrupting future discounting to promote improved adherence to lifestyle interventions aimed at reducing NCD risk.

Time and risk preferences and the perceived effectiveness of incentives to comply with diabetic retinopathy screening among older adults with type 2 diabetes

Behavioral economics has the potential to inform the design of incentives to improve disease screening programs by accounting for various behavioral biases. We investigate the association between multiple behavioral economics concepts and the perceived effectiveness of incentive strategies for behavioral change among older patients with a chronic disease. This association is examined by focusing on diabetic retinopathy screening, which is recommended but very variably followed by persons living with diabetes. Five time and risk preference concepts (i.e., utility curvature, probability weighting, loss aversion, discount rate, and present-bias) are estimated simultaneously in a structural econometric framework, based on a series of deliberately-designed economic experiments offering real money. We find that higher discount rates and loss aversion and lower probability weighting are significantly associated with lower perceived effectiveness of intervention strategies whereas present-bias and utility curvature have an insignificant association with it. Finally, we also observe strong urban vs. rural heterogeneity in the association between our behavioral economic concepts and the perceived effectiveness of intervention strategies.

Putting prospection into practice: Methodological considerations in the use of episodic future thinking to reduce delay discounting and maladaptive health behaviors

In recent years, episodic future thinking (EFT) has emerged as a promising behavioral intervention to reduce delay discounting or maladaptive health behaviors; however, considerable methodological heterogeneity in methods for eliciting engagement in EFT has been observed in prior research. In this narrative review, we briefly describe methods for generating EFT cues, the content of EFT cues, common control conditions for experiments utilizing EFT, and considerations for cue delivery and implementation. Where possible, we make suggestions for current best practices in each category while identifying gaps in knowledge and potential areas of future research. Finally, we conclude by using the NIH Stage model to better frame the current state of the literature on EFT and propose gaps to be addressed if EFT is to be both an efficacious and effective behavioral intervention.

Testing and Optimizing Guided Thinking Tasks to Promote Physical Activity: Protocol for a Randomized Factorial Trial (Preprint)

Background

Objective

Methods

Results

Conclusions

Trial Registration

International Registered Report Identifier (IRRID)