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临床试验/NCT02461693
NCT02461693已完成不适用

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

University of Alabama at Birmingham0 个研究点目标入组 205 人开始时间: 2015年6月最近更新:
适应症
干预措施
相关药物

试验速览

阶段
不适用
状态
已完成
入组人数
205
主要终点
Mood State Score on POMS-2 Test

研究概览

简要总结

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.

研究设计

研究类型
Interventional
分配方式
Randomized
干预模型
Parallel
主要目的
Other
盲法
Double (Participant, Investigator)

盲法说明

Participants, study personnel interacting with participants, and investigators were blinded. Only the study statistician knew treatment assignments.

入排标准

年龄范围
18 Years 至 —(Adult, Older Adult)
性别
All
接受健康志愿者

入选标准

  • 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)

排除标准

  • 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

研究组 & 干预措施

Caffeine

Experimental

One-time treatment with 200mg caffeine pill

干预措施: Caffeine (Drug)

Placebo

Placebo Comparator

One-time treatment with lactose-based placebo pill

干预措施: Placebo (Drug)

结局指标

主要结局

Mood State Score on POMS-2 Test

时间窗: 30 minutes post pill consumption

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.

Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Proportion Correct (Out of 60)

时间窗: 45 to 105 minutes post pill consumption

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

Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Number Correct, Number of False Alarm Hits

时间窗: 45 to 105 minutes post pill consumption

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

Vigilance Score on Computer-based Test Using Random, Visual Stimulus: Mean Time to a Correct Hit

时间窗: 45 to 105 minutes post pill consumption

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

次要结局

未报告次要终点

研究者

申办方类型
Other
责任方
Principal Investigator
主要研究者

David Allison, Phd

Associate Dean for Science, School of Public Health

University of Alabama at Birmingham

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