MINDD 3: Prediabetes and Delay Discounting

Study Overview
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Brief Summary
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The proposed research will translate research on delay discounting to the prevention of Type 2 diabetes (T2D) in persons with prediabetes. In this study, the investigators will verify target engagement (DD) by examining if EFT improves DD under conditions shown to increase discounting of the future. Prediabetics will be randomized to receive EFT/ERT in a factorial design when experiencing simulated poverty/neutral conditions, respectively. The effects will be measured on DD. The investigators predict that poverty conditions will increase discounting of the future for ERT subjects, but those receiving EFT will show levels of DD similar to levels observed for participants in the wealth condition.

Detailed Description
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The prevention of Type 2 diabetes in an obese person with prediabetes requires developing a healthier lifestyle. The rational approach for someone with prediabetes would be to eat healthier, be more active, lose weight, and manage their comorbidities. However, preliminary research suggests that individuals with Type 2 diabetes discount the future and engage in behaviors that maximize current pleasure and short-term gain; thus, daily choices needed to improve future health are rare in this population. Delay discounting (DD) describes the choice of smaller immediate versus larger delayed rewards. This behavioral process is related to a wide variety of health choices, ranging from preventive health to behavioral and medical regimen adherence, including regimens used for Type 2 diabetes. The investigators believe that DD provides a target for one type of self-regulation that can improve a wide variety of health behaviors and medical adherence. Research from our laboratories has shown that episodic future thinking (EFT), a form of prospection which reduces the bias towards immediate gratification, activates brain regions involved in planning and prospection such that future rewards have increased value and the extent of delay discounting is reduced. Cueing individuals to think about future events during inter-temporal decision-making reduces the rate of DD, eating in and outside of the laboratory, and smoking behavior. The overarching goal of this research is to use an experimental medicine approach to translate basic research on DD and EFT into clinical interventions to prevent the transition from prediabetes to a diagnosis of Type 2 diabetes.

Official Title
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Delay Discounting as a Target for Self-Regulation in Prediabetes

Conditions
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PreDiabetes

Intervention / Treatment
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* Behavioral: Episodic Future Thinking
* Behavioral: Episodic Recent Thinking
* Behavioral: Scarcity Narrative
* Behavioral: Neutral Narrative


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Prediabetes: Participants must have a diagnosis of prediabetes within the last 2 years or meet criteria for prediabetes. The American Diabetes Association guidelines defines prediabetes as Fasting Plasma Glucose (FPG) 100-125 mg/dl, 2h glucose 140-199 mg/dl after Oral Glucose Tolerance Test (OGTT), or hemoglobin A1c (HbA1c) approximately 5.7-6.4%. Comorbidities: Participants must have a history of comorbid diagnosis such as hypertension and/or hyperlipidemia to participate in the behavioral portion of this study. Hypertension is defined as blood pressure greater than 140/90 on two separate occasions at least one week apart, or medical management for hypertension (i.e. medications including Lisinopril and Diovan). Dyslipidemia is defined by LDL greater than 130 mg/dl, or non-fasting non HDL cholesterol ≥160mg/dL or medical management for dyslipidemia (medications including Niacin, Lovastatin). Exclusion Criteria: Type 2 Diabetes: Individuals will be excluded if they have Type 2 Diabetes. Pregnancy: Women who are pregnant or lactating will be excluded from participation. Conditions that affect adherence: Participants should not have a condition that would limit participation which include medical conditions that would affect individuals' ability to use the computer for prolonged period of time; leave the individual unable to ambulate; or current diagnoses of an eating disorder (anorexia, bulimia,), unmanaged psychiatric disorder (depression, anxiety, attention deficit hyperactivity disorder (ADHD), schizophrenia), or an intellectual impairment that would impact study adherence. Abnormal glucose related to medications: Participants should not be taking medications that would limit participation and cause abnormal glucose levels (e.g. atypical antipsychotic medications or glucocorticoids) including diabetic drugs such as Metformin. Unwilling or unable to eat study food: Participants who are unwilling or not able to eat the study food (a PowerBar) will not be able to take part in this study. Prior participation in similar studies: Individuals who have recently participated in a laboratory study using similar methods may also be excluded. Do not meet discounting criteria: Individuals who do not meet discounting criteria (e.g. nonsystematic discounting) on a delay discounting task may be excluded.

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: Basic Science
Allocation: Randomized
Intervention Model: Factorial Assignment
Interventional Model Description: Participants will be assigned to complete an episodic future or recent thinking task and asked to describe positive events for different time periods.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Episodic Future Thinking (EFT) & Neutral Narrative<br>Participants will complete an episodic thinking task to generate episodic cues where they will list and describe events for different time periods.The episodic component of the thinking task will occur while the participants are asked to describe what they are imagining about each event (e.g., vacations, weddings, parties, and so forth). EFT participants will list positive future events they are looking forward to and list events that could happen at different general future time points (e.g., 1 month, 2-6 months, 7-12 months). Participants will also be asked to think about a neutral narrative that describes a situation in which changes to their income are neutral or minimal | Behavioral: Episodic Future Thinking<br>* Participants will be instructed to use their episodic future cues as they engage in different decision making tasks.<br>* Other names: EFT;Behavioral: Neutral Narrative<br>* Participants will read a narrative in which they are asked to imagine a scenario in which they have been transferred between departmental jobs, with little change in salary/commute.<br>* Other names: Neutral;|
| Active Comparator: Episodic Recent Thinking (ERT) & Neutral Narrative<br>Participants will complete an episodic recent thinking task to generate episodic cues where they will list and describe events for different time periods. The episodic component of the thinking task will occur while the participants are asked to describe what they are imagining about each event. ERT participants will list positive recent events they enjoyed and list events that happened recently (e.g. 1 - 7 days ago). Participants will also be asked to think about a neutral narrative that describes a situation in which changes to their income are neutral or minimal (e.g. department job transfer). | Behavioral: Episodic Recent Thinking<br>* Participants will be instructed to use their episodic recent cues as they engage in different decision making tasks.<br>* Other names: ERT;Behavioral: Neutral Narrative<br>* Participants will read a narrative in which they are asked to imagine a scenario in which they have been transferred between departmental jobs, with little change in salary/commute.<br>* Other names: Neutral;|
| Experimental: Episodic Future Thinking (EFT) & Scarcity Narrative<br>Participants will complete an episodic thinking task to generate episodic cues where they will list and describe events for different time periods.The episodic component of the thinking task will occur while the participants are asked to describe what they are imagining about each event (e.g., vacations, weddings, parties, and so forth). EFT participants will list positive future events they are looking forward to and list events that could happen at different general future time points (e.g., 1 month, 2-6 months, 7-12 months). Participants will also be asked to think about a narrative to induce a scarcity mindset by describing a situation in which changes to their income are negative (e.g. loss of job). | Behavioral: Episodic Future Thinking<br>* Participants will be instructed to use their episodic future cues as they engage in different decision making tasks.<br>* Other names: EFT;Behavioral: Scarcity Narrative<br>* Participants will read a narrative to induce a scarcity mindset, in which they are asked to imagine a scenario in which they have lost their job and have no current secondary income.<br>* Other names: Scarcity;|
| Experimental: Episodic Recent Thinking (ERT) & Scarcity Narrative<br>Participants will complete an episodic recent thinking task to generate episodic cues where they will list and describe events for different time periods. The episodic component of the thinking task will occur while the participants are asked to describe what they are imagining about each event. ERT participants will list positive recent events they enjoyed and list events that happened recently (e.g. 1 - 7 days ago). Participants will also be asked to think about a narrative to induce a scarcity mindset by describing a situation in which changes to their income are negative (e.g. loss of job). | Behavioral: Episodic Recent Thinking<br>* Participants will be instructed to use their episodic recent cues as they engage in different decision making tasks.<br>* Other names: ERT;Behavioral: Scarcity Narrative<br>* Participants will read a narrative to induce a scarcity mindset, in which they are asked to imagine a scenario in which they have lost their job and have no current secondary income.<br>* Other names: Scarcity;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Delay Discounting | Delay Discounting will be measured using monetary Delay Discounting tasks with $100 as the delayed reward. Delay discounting is assessed using Area Under the Curve (AUC), or time*indifference point/delay. AUC for delay discounting included time (x-axis) and indifference point (y-axis), or the amount of money at which the immediate and delayed options are approximately equal. Indifference points are a percentage of the max amount (range 0 - 100). AUC adds the calculated areas for each timepoint from the previous timepoint. Ordinal AUC was used as the measure. Ordinal AUC normalizes the horizontal axis time points to have equal distances between them. AUC ranges from 0 (most impulsive, did not choose delay) to 100 (least impulsive, always chose delay). This is the difference in delay discounting between session 2 and session 1. Larger numbers indicate a decrease in discounting, or less impulsive, while smaller/negative numbers indicate an increase in discounting, or more impulsive. | Delay Discounting will be measured at baseline (session 1) and after receiving EFT/ERT and Scarcity/Narrative (within about 2 weeks) | 
| Reinforcing Value of Food | Reinforcing value of food was measured using the relative reinforcing efficacy questionnaire in which participants are asked how many portions of food they would purchase at various prices. Intensity is the number of portions they would purchase and consume when the price is $0. | Session 2 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Working Memory Span | Backwards Corsi is a task that assesses visuo-spatial short term working memory. Participants are asked to watch a series of squares on a computer screen and repeat the sequence backwards. This is done several times and the highest number of correctly remembered locations is the span score, with a possible score of 2 - 9 locations total. Span score represents the number of locations that can be recalled backwards. Larger span scores indicate more locations can be remembered and recalled correctly backwards. This is the difference in score between session 2 and session 1. Larger numbers indicate greater change during the experimental manipulation or better working memory, while smaller or negative numbers indicates lower working memory during the experimental manipulation versus baseline. Numbers close to 0 represent little to no change. | Working Memory will be measured at baseline (session 1) and after receiving EFT/ERT Scarcity/Neutral intervention (up to 2 weeks post-baseline) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Delay Discounting, Episodic Future Thinking