This 12 week pilot study of 90 obese men and women with metabolic syndrome explores effecis of expectancies associated with different clinical trials designs for a dietary supplement. Metabolic syndrome and obesity are related risk factors for diabetes and cardiovascular disease; having both factors accelerates risk. The placebo effect is used to model patient expectancy using a concealed placebo. Qualifying volunteers will be told they are being recruited for a 3-arm trial of a natural product plus standard education for the condition. Randomization is to one of the three arms with subjects respectively told the following: one arm will be told they are taking the active agent; the second arm will be told they are in a double-blind placebo-controlled trial; the third arm will be given education alone without concealment. Subjects will be aware of group assignment. The two arms taking capsules will actually receive a placebo. The comparison groups will therefore be those with a 100% expectancy of taking an active agent, 50% expectancy of taking it, and 0 expectancy. A true active will not be used and thus will not impinge on outcomes. Subjects will be told that the reason for the 3-arm design is to study the effect of different trial designs together with agent efficacy. They will be told that the supplement being studied is a combination of two ingredients that is intended to decrease hunger, increase energy, and improve insulin function. Scientific rationale and enthusiasm for the therapy will be conveyed to patients to maximize the placebo effect. The placebo effect has been reported to result in alterations of perceptual, behavioral and physiologic outcomes, however these categories have not been clearly distinguished in earlier studies. We will explore the character and correlates of expectancy and the placebo effect associated with dietary supplements. Measures of differences between groups will be anthropometric, behavioral, metabolic, hormonal, and psychometric. Correlates of placebo/expectancy-response will be explored including personality and hormonal factors and relevant genotypes. The design, education and concealment procedures will be evaluated for use in future studies of placebo and expectancy.
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