Placebo Effect
Conditions
Brief summary
This study aims to assess if tablet size, due to placebo effect, alters participants' performance on cognitive tests after consuming caffeine. Participants will be randomly assigned to one of four groups: 1) 90 mg caffeine with a 1 mm diameter sucrose pillule; 2) no caffeine with the small sucrose pillule; 3) 90 mg caffeine with a 5 mm sucrose pillule; 4) no caffeine with the large sucrose pillule.
Detailed description
Background: A capsule's physical design (e.g. shape, size, and color) affects individuals' perception of drug efficacy; that is, how well a drug is likely to work. The goal of this study is to assess the effects tablet size may have on participant's performance on cognitive testing since research has found differences between preparation methods. Method: 120 participants will be randomly assigned to one of four groups: 1) 90 mg caffeine with a 1 mm diameter sucrose pillule; 2) no caffeine with the small sucrose pillule; 3) 90 mg caffeine with a 5 mm sucrose pillule; 4) no caffeine with the large sucrose pillule. Participants will consume the designated placebo tablet with water (caffeinated or non-caffeinated); then, participants will provide weekly caffeine intake and complete the neutral portion of Velten's Mood Induction Procedure until 30 minutes have passed to allow for caffeine activation. Participants will complete the Stroop test, Trial Making Tests A and B, and the Rey Auditory Verbal Learning Test. Previous literature, as far as the author knows, relied on evaluating drug efficacy based on appearance alone. This study aims to assess if tablet size, due to placebo effect, alters participants' performance on cognitive tests after consuming caffeine.
Interventions
DRUGCaffeine Anhydrous with small sucrose pill
caffeine anhydrous that has been weighed out to 90 mg per dose presented with a 1 mm sucrose pillule
OTHERPlacebo - large sucrose pill
sucrose pillules of 5 mm diameter will be given to all participants in the large pill groups
DRUGCaffeine Anhydrous with large sucrose pill
caffeine anhydrous that has been weighed out to 90 mg per dose presented with a 5 mm sucrose pillule
OTHERPlacebo - small sucrose pill
sucrose pillules of 1 mm diameter will be given to all participants in the small pill groups
Sponsors
University of Colorado, Denver
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Masking description
Participants will not be made aware if they have or have not received caffeine to not bias results.
Intervention model description
Participants will be randomly assigned to one of four groups: 1\) 90 mg caffeine with a 1 mm diameter sucrose pillule; 2) no caffeine with the small sucrose pillule; 3) 90 mg caffeine with a 5 mm sucrose pillule; 4) no caffeine with the large sucrose pillule.
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Fluent in written and spoken English * Ability to see color * No uncontrolled high blood pressure * No allergies to caffeine or sucrose * No history of heart disease * No untreated anxiety or depression * Non-pregnant * No caffeine consumed the day of participation
Exclusion criteria
* Not fluent in written and/or spoken English * Uncontrolled high blood pressure * Color-blindness * Allergies to caffeine and/or sucrose * History of heart disease * Untreated anxiety or depression * Pregnant * Consumed caffeine on the day of participation
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Stroop Color test | Within 90 minutes of receiving informed consent. Actual task time: approximately 1.5 minutes | Measures processing speed. 100-item, time-trial task where participants read the color of printed items on the task paper as quickly as possible for 45 seconds. Scores are measured in the number of correct responses within the allotted time. |
| Stroop Word test | Within 90 minutes of receiving informed consent. Actual task time: approximately 1.5 minutes | Measures processing speed. 100-item, time-trial task where participants read color names printed on the task paper as quickly as possible for 45 seconds. Scores are measured in the number of correct responses within the allotted time. |
| Trail Making task A | Within 90 minutes of receiving informed consent. Actual task time: approximately 2 minutes | Measures processing speed. 25 item, time-trial task where participants must connect numbers in order as quickly as possible. Scores are measured by the amount of time (in seconds) for participants to complete the task. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Stroop Color-and-Word test | Within 90 minutes of receiving informed consent. Actual task time: approximately 2 minutes | Measures processing speed. 100-item, time-trial task where participants must read the color of the ink instead of color names printed on the task paper as quickly as possible for 45 seconds. Scores are measured in the number of correct responses within the allotted time. |
| Trail Making task B | Within 90 minutes of receiving informed consent. Actual task time: approximately 3 minutes | Measures processing speed. 25 item, time-trial task where participants must connect numbers and letters in order (e.g. 1-A-2-B, etc.) as quickly as possible. Scores are measured by the amount of time (in seconds) for participants to complete the task. |
| Rey Auditory Verbal Learning test | Within 90 minutes of receiving informed consent. Actual task time: approximately 40 minutes | Measures memory. 30-item, 2 section task where participants are read 15 words and asked to recall as many words as possible in the first section. A second set of 15 words is then introduced and participants recall those. The second section consists of revisiting the original set of words and recalling as many of those. Scores are measured by the total words remembered in section one, and another score for the total intrusions from the second list into the recall of section two. |
Countries
United States
Outcome results
None listed