The effects of a caffeine placebo and suggestion on blood pressure, heart rate, well-being and cognitive performance
Walach H, Schmidt S, Dirhold T, Nosch S
International journal of psychophysiology : official journal of the International Organization of Psychophysiology · 28 citas
Etiquetas de revisión
Financiación no declaradaDatos neutrales que nuestra revisión registró sobre cómo se hizo este estudio. Describen el método, nunca si nos gusta el resultado.
Cómo se estudió
- Diseño
- Ensayo controlado aleatorizado (indexado por PubMed)
- Estudiado en
- Personas
- Resultado principal
- Marcadores de salud y funcionamiento
Quién lo pagó
- Financiación
- Financiación no declarada
Publicación
- Publicado
- 2002-03-01 · Int J Psychophysiol · vol. 43 · número 3 · págs. 247–260
- Editorial
- Elsevier BV
- Citado
- 46 citas · más que el 78% de estudios similares · 1.3× el promedio de su campo
- Referencias
- 24 trabajos
- Acceso
- De pago
- Áreas de investigación
- Pain Management and Placebo Effect · Coffee research and impacts · Blood Pressure and Hypertension Studies
- Palabras clave
- expectancy effects, suggestion, blood pressure, heart rate, well-being, cognitive performance
- MeSH
- humans, caffeine, central nervous system stimulants, suggestion, double-blind method, affect, cognition, psychomotor performance, blood pressure, heart rate, adolescent, adult, child, female, male
4 autores
- Harald Walach🇩🇪 · autor de correspondenciaUniversity of Freiburg; University Medical Center Freiburg
- Stefan Schmidt🇩🇪University of Freiburg; University Medical Center Freiburg
- Thomas Dirhold🇩🇪University of Freiburg; University Medical Center Freiburg
- Sonja Nosch🇩🇪University of Freiburg; University Medical Center Freiburg
Resumen
El texto original del estudio, en el idioma en que se publicó.
We studied the effect of suggestion and different instructions in a balanced placebo design. One hundred and fifty-nine subjects were randomized into a 2*4 factorial design. All subjects except a control group received a caffeine placebo. Subjects were randomized to a condition which was identical to an earlier study, or received an information about scientifically proven effects of caffeine (factor 1). The second factor varied instructions: subjects were either made to expect coffee, no coffee or were in a double blind condition and were told either coffee or placebo would be applied. Dependent measures were blood pressure, heart rate, well-being and a cognitive task. There was one main effect of the instruction factor (P=0.03) on diastolic blood pressure, with the group 'told caffeine' reporting significantly smaller decrease in diastolic blood pressure than controls and subjects in the double blind condition. There were no other main effects on both the instruction or suggestion factor, and no interactions. Contrary to the literature, instruction effects were very small. This was apparently due to the fact that placebo-caffeine in the dose used in this study--one cup of strong 'coffee'--did not produce expectancy effects strong enough to affect the parameters measured. It is concluded that the placebo-caffeine research paradigm is not suitable for researching instruction effects in Germany, and that reported effects should be reproduced with tighter controls.
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