“Much of a drug response is related to nonspecific factors. Perceptual characteristics of drug preparations likely play a major role in expectancy and response. This study focused on perceptual characteristics of a preparation related to anticipated effect: capsule color, capsule size, and preparation form (capsule versus tablet). College students ranked capsules for perceived strength based on capsule size, categorized capsules in terms of anticipated pharmacological effect based on color, and evaluated strength based on preparation form. Data showed nonchance distributions for nine capsule colors in anticipated action, with specific effects for four colors. A significant difference between capsule and tablet for perceived strength was found, as was a trend relating capsule size to perceived drug strength. Discussion centered on awareness and consideration of drug perceptual characteristics in support of drug efficacy.”
J Clin Psychopharmacol. 1982 Aug;2(4):245-8.
An investigation of drug expectancy as a function of capsule color and size and preparation form.
Buckalew LW, Coffield KE.
“There is accumulating evidence from different methodological approaches that the placebo effect is a neurobiological phenomenon. Behavioral, psychophysiological, and neuroimaging results have largely contributed to accepting the placebo response as real. A major aspect of recent and future advances in placebo research is to demonstrate linkages between behavior, brain, and bodily responses. This article provides an overview of the processes involved in the formation of placebo responses by combining research findings from behavioral, psychophysiological, and neuroimaging methods. The integration of these different methodological approaches is a key objective, motivating our scientific pursuits toward a placebo research that can inform and guide important future scientific knowledge.”
The Placebo Effect: Advances from Different Methodological Approaches
Karin Meissner1,2,*, Ulrike Bingel3,*, Luana Colloca4,5,*, Tor D. Wager6,*, Alison Watson7,*, and Magne Arve Flaten8,*
The Journal of Neuroscience, 9 November 2011, 31(45): 16117-16124