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

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

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.

Study Overview

• Status: Completed
• Conditions: Mood; Cognitive Ability, General; Caffeine; Affect
• Intervention / Treatment: Drug: Caffeine; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 205
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University of Alabama at Birmingham
• Investigators: Principal Investigator: David B Allison, PhD, University of Alabama at Birmingham

Publications and helpful links

General Publications

• George BJ, Li P, Lieberman HR, Pavela G, Brown AW, Fontaine KR, Jeansonne MM, Dutton GR, Idigo AJ, Parman MA, Rubin DB, Allison DB. Randomization to randomization probability: Estimating treatment effects under actual conditions of use. Psychol Methods. 2018 Jun;23(2):337-350. doi: 10.1037/met0000138. Epub 2017 Apr 13.

Study record dates

Study Major Dates

• Study Start: June 1, 2015
• Primary Completion (Actual): October 1, 2015
• Study Completion (Actual): October 1, 2015

Study Registration Dates

• First Submitted: June 1, 2015
• First Submitted That Met QC Criteria: June 2, 2015
• First Posted (Estimate): June 3, 2015

Study Record Updates

• Last Update Posted (Actual): July 12, 2017
• Last Update Submitted That Met QC Criteria: June 13, 2017
• Last Verified: June 1, 2017

More Information

Terms related to this study

• Keywords: Randomized Controlled Trial; Mood; Vigilance; Probability
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Purinergic Antagonists; Purinergic Agents; Phosphodiesterase Inhibitors; Purinergic P1 Receptor Antagonists; Central Nervous System Stimulants; Caffeine
• Other Study ID Numbers: F150410009

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Raw de-identified data will be posted as a replication data set on ICPSR after publication of results in a journal. Data will be free to download and accessible to anyone with access to ICPSR replication data sets.

Drug and device information, study documents

• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No