Evaluating the Role of Expectations in Response to Caffeine Consumption: An RCT

Study Overview
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Brief Summary
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The purpose of this project is to examine the effect of expectancy on mood and alertness after consumption of caffeine treatment or placebo control pill, given that participants know their probability for receiving the caffeine versus placebo pill. Participants will be randomly assigned a probability (ranging from 0-100%) of receiving caffeine vs. placebo, and this probability will be revealed to them before consumption of the assigned pill and subsequent cognitive testing. At the time of consumption, neither study staff administering the intervention nor participants will know for certain which pill is given to each participant. Pill assignment will depend on pre-determined randomization probabilities, which will be provided and assigned by the study statistician. By revealing participants' individual probability of receiving the caffeine pill, we will induce positive or negative expectancies regarding likelihood for receipt of the caffeine pill. These experimental manipulations will: 1) estimate the effect of expectancy on cognitive and affective outcomes, and 2) allow for a more direct estimate of the effect of the caffeine pill under real-world conditions than would a conventional randomized trial.

Official Title
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Evaluating the Role of Expectations in Response to Caffeine Consumption: A Randomized Control Trial

Conditions
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Caffeine, Affect, Cognitive Ability, General, Mood

Intervention / Treatment
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* Drug: Caffeine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years-old or older available to participate on the dates specified willing to take a caffeine or placebo pills at study session willingness to abstain from caffeine for 12 hours prior to study visit (8:30pm-8:30am) UAB employees or students with some college education (including current enrollment) Exclusion Criteria: self-reported use of ADHD medication self-reported use of anxiety medication self-reported use of sleep medication self-reported use of nicotine products self-reported lactose intolerance self-reported uncorrected vision self-reported pregnancy or trying to become pregnant

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Caffeine<br>One-time treatment with 200mg caffeine pill | Drug: Caffeine<br>* 200mg delivered as pill; one-time dose<br>|
| Placebo Comparator: Placebo<br>One-time treatment with lactose-based placebo pill | Drug: Placebo<br>* Lactose-based pill; one-time dose<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mood State Score on POMS-2 Test | Profile of Mood States (POMS-2)- Volunteers rated a series of 65 mood-related adjectives with regard to how they were feeling right now on a scale of 0 (not at all) to 4 (extremely). The adjectives factor into six mood sub-scales: Tension-Anxiety; Depression-Dejection; Anger-Hostility; Vigor-Activity; Fatigue-Inertia; Confusion-Bewilderment and a Total Mood Disturbance score which aggregates the six sub-scales into a single variable. - from our publication. The minimum and maximum possible raw scores were: 0 and 40 for Tension-Anxiety, 0 and 52 for Depression-Dejection, 0 and 44 for Anger-Hostility, 0 and 36 for Vigor-Aactivity, 0 and 24 for Fatigue-Inertia, 0 and 40 for Confusion-Bewilderment, -36 and 200 for Total Mood Disturbance, and 0 and 24 for Friendliness. For Friendliness and Vigor-Activity, the more positively a person feels, the higher the score. For all other sub-scales and Total Mood Disturbance, the more negatively a person feels, the higher the score. | 30 minutes post pill consumption | 
| Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Proportion Correct (Out of 60) | Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication | 45 to 105 minutes post pill consumption | 
| Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Number Correct, Number of False Alarm Hits | Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication | 45 to 105 minutes post pill consumption | 
| Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Mean Time to a Correct Hit | Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication | 45 to 105 minutes post pill consumption | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vigilance, Mood, Randomized Controlled Trial, Probability