Expectancy effect: Impact of pill administration on cognitive performance in healthy seniors

Barry S. Oken; Kristin Flegal; Daniel Zajdel; Shirley Kishiyama; Mitchell Haas; Dawn Peters

doi:10.1080/13803390701775428

Expectancy effect: Impact of pill administration on cognitive performance in healthy seniors

Barry S. Oken, Kristin Flegal, Daniel Zajdel, Shirley Kishiyama, Mitchell Haas, Dawn Peters

Research output: Contribution to journal › Article › peer-review

65 Scopus citations

Abstract

Expectancy or placebo effects on cognitive function have not been well studied. To determine the effect of taking pills on cognitive function, 40 participants were randomly assigned to a pill or no-pill condition. Healthy seniors who took a 2-week supply of methylcellulose pills, which they were told was an experimental cognitive enhancer, were compared to seniors not taking any pills. There were 2 primary outcome measures defined prior to the study - Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List delayed recall and Stroop color word task time - as well as 7 other cognitive outcome measures. There was a significant effect of pill taking on the 2 primary outcome measures. There was also an effect of pill taking on choice reaction time and Word List immediate recall but not on the other 5 secondary cognitive outcome measures. In an exploratory analysis of potential predictors of the expectancy effect, perceived stress and self-efficacy but not personality traits interacted with the pill-taking effect on cognitive function. Further characterizing and understanding this observed expectancy effect is important to maximize cognitive health and improve clinical trial design.

Original language	English (US)
Pages (from-to)	7-17
Number of pages	11
Journal	Journal of Clinical and Experimental Neuropsychology
Volume	30
Issue number	1
DOIs	https://doi.org/10.1080/13803390701775428
State	Published - Jan 2008

Keywords

Attention
Geriatrics
Memory
Placebo effect
Self-efficacy
Stress

ASJC Scopus subject areas

Clinical Neurology
Neuropsychology and Physiological Psychology
Neurology
Clinical Psychology

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10.1080/13803390701775428

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title = "Expectancy effect: Impact of pill administration on cognitive performance in healthy seniors",

abstract = "Expectancy or placebo effects on cognitive function have not been well studied. To determine the effect of taking pills on cognitive function, 40 participants were randomly assigned to a pill or no-pill condition. Healthy seniors who took a 2-week supply of methylcellulose pills, which they were told was an experimental cognitive enhancer, were compared to seniors not taking any pills. There were 2 primary outcome measures defined prior to the study - Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List delayed recall and Stroop color word task time - as well as 7 other cognitive outcome measures. There was a significant effect of pill taking on the 2 primary outcome measures. There was also an effect of pill taking on choice reaction time and Word List immediate recall but not on the other 5 secondary cognitive outcome measures. In an exploratory analysis of potential predictors of the expectancy effect, perceived stress and self-efficacy but not personality traits interacted with the pill-taking effect on cognitive function. Further characterizing and understanding this observed expectancy effect is important to maximize cognitive health and improve clinical trial design.",

keywords = "Attention, Geriatrics, Memory, Placebo effect, Self-efficacy, Stress",

author = "Oken, {Barry S.} and Kristin Flegal and Daniel Zajdel and Shirley Kishiyama and Mitchell Haas and Dawn Peters",

note = "Funding Information: This research was funded in part by National Institutes of Health (NIH) Grants U19 AT002656, P30 AG008017, and M01 RR000334. An abstract based on this research was presented at the November 2005 annual meeting of the Society for Neuroscience, in Washington, DC. The authors thank Andy Fish who served as one of the unblinded researchers dispensing pills and providing feedback. The authors have reported no conflicts of interest.",

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AU - Haas, Mitchell

AU - Peters, Dawn

N1 - Funding Information: This research was funded in part by National Institutes of Health (NIH) Grants U19 AT002656, P30 AG008017, and M01 RR000334. An abstract based on this research was presented at the November 2005 annual meeting of the Society for Neuroscience, in Washington, DC. The authors thank Andy Fish who served as one of the unblinded researchers dispensing pills and providing feedback. The authors have reported no conflicts of interest.

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Expectancy effect: Impact of pill administration on cognitive performance in healthy seniors

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Keywords

ASJC Scopus subject areas

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