Effect of Ghrelin on Decision-Making

Study Overview
=================
Brief Summary
-----------------
This study evaluates the effect of the hunger hormone ghrelin on human decision-making. Participants will be given an injection of ghrelin or saline on different study days and will then be asked to make a series of computer-based decisions. The investigators hypothesize that ghrelin will increase participant's preference for energy-dense foods and will also increase impulsiveness in decision making.

Detailed Description
-----------------
Ghrelin is a hormone made by the stomach that stimulates hunger and feeding behavior. How ghrelin affects human decision-making is poorly understood. This study will investigate the effect of ghrelin on nutrition-related and time-based decisions in humans. Participants eye movements will be tracked by a computer during the decision-making process.

Official Title
-----------------
Effect of Ghrelin on Nutritional and Financial Decision-Making

Conditions
-----------------
Healthy Volunteers, Obesity

Intervention / Treatment
-----------------
* Drug: Ghrelin
* Drug: Saline


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Ability to speak and understand English BMI of 18.0 - 24.9 kg/m2 or 30.0 - 50.0 kg/m2 Exclusion Criteria: Diagnosis of diabetes mellitus (including gestational diabetes) Active infections History of malignant or inflammatory conditions, such as rheumatoid arthritis and inflammatory bowel disease History of myocardial infarction or congestive heart failure Active liver or kidney disease Uncontrolled hypertension Pituitary or adrenal disorders or neuroendocrine tumors History of anorexia nervosa, bulimia, or eating disorders not otherwise specified (NOS); Score of at risk on the EAT-26 eating disorder screening tool Diagnosis of attention-deficient/hyperactivity disorder (ADHD) Malabsorptive gastrointestinal disease, gastroparesis, or history of gastrointestinal surgery Pregnancy or lactation Requirement of daily medications that alter gastrointestinal function (including, but not limited to, glucocorticoids, psychotropics, narcotics, and metoclopramide). Requirement of glasses for impaired vision (including reading glasses). Subjects who wear contact lenses for vision correction will not be excluded. Insufficient visual acuity to read and interpret the decision stimuli Insufficient motor capabilities to press a button, move the joystick, or move their eyes to indicate a response

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy Subjects - Ghrelin<br>Healthy subjects will arrive after consuming a standard meal 60 minutes prior to study onset. They will receive a single subcutaneous injection of human synthetic Acyl Ghrelin at the start of the study. 5 minutes post-injection, the subjects will receive written instructions and begin their first decision-making task on a computer. | Drug: Ghrelin<br>* Subjects will receive a subcutaneous injection of synthetic acyl ghrelin (12 µg/kg) at the start of the study.<br>* Other names: Octanoyl Ghrelin;|
| Placebo Comparator: Healthy Subjects - Saline<br>Healthy subjects will arrive after consuming a standard meal 60 minutes prior to study onset. They will receive a single subcutaneous injection of 0.9% saline at the start of the study. 5 minutes post-injection, the subjects will receive written instructions and begin their first decision-making task on a computer. | Drug: Saline<br>* Subjects will receive a subcutaneous injection of saline (0.9%) at the start of the study.<br>|
| Experimental: Obese Subjects - Ghrelin<br>Obese subjects will arrive after consuming a standard meal 60 minutes prior to study onset. They will receive a single subcutaneous injection of human synthetic Acyl Ghrelin at the start of the study. 5 minutes post-injection, the subjects will receive written instructions and begin their first decision-making task on a computer. | Drug: Ghrelin<br>* Subjects will receive a subcutaneous injection of synthetic acyl ghrelin (12 µg/kg) at the start of the study.<br>* Other names: Octanoyl Ghrelin;|
| Placebo Comparator: Obese Subjects - Saline<br>Obese subjects will arrive after consuming a standard meal 60 minutes prior to study onset. They will receive a single subcutaneous injection of 0.9% saline at the start of the study. 5 minutes post-injection, the subjects will receive written instructions and begin their first decision-making task on a computer. | Drug: Saline<br>* Subjects will receive a subcutaneous injection of saline (0.9%) at the start of the study.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of Ghrelin on food choices in Task 1. | The difference in the proportion of healthy and unhealthy choices in the Saline and Ghrelin conditions. | Approximately 25 minutes | 
| Effect of Ghrelin on temporal choices in Task 2 | The difference in the proportion of smaller sooner and larger later choices in the Saline and Ghrelin conditions | Approximately 25 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dwell time on each choice during Task 1 | For eye-tracking, total dwell time (in ms) on each item in a food choice will be compared in both experimental conditions. | Approximately 25 minutes | 
| Number of fixations on foods during Task 1 | The total number of fixations on each food option will be compared in both experimental conditions. | Approximately 25 minutes | 
| Dwell time on each choice during Task 2 | For eye-tracking, total dwell time (in ms) on each item in the monetary choice will be compared in both experimental conditions. | Approximately 25 minutes | 
| Number of fixations on foods during Task 2 | The total number of fixations on each monetary option will be compared in both experimental conditions. | Approximately 25 minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Decision-making, Ghrelin, Healthy Volunteers, Obese