Quantifying placebo effect on psychomotor and cognitive functions in adult healthy human volunteers

Placebo has been found to have beneficial effects in manypsychoneurological conditions like pain, depression, Parkinson’s disease andmany others. It can be conceptualized as healing power of mind. The effect hasbeen seen in clinical trial as well as clinical practice settings. Alternativetherapies with elaborate rituals and distinct environmental cues can havepronounced and clinically significant placebo effect. It is imperative to studythe placebo phenomenon from basic science, clinical trial and ethicalperspectives to better understand how placebo operate in clinical settings. Neurobiologically,they have been found to be due to release of endogenous opioids and dopamine.Dopamine has also been studied to be central to mechanism of attention andworking memory in human beings. It has been imperative that intactconsciousness, preserved mental faculties and moderate pathological dysfunctionare needed for demonstration of pathological effect. However, a negativeinteraction has been studied between drug and placebo and in some cases effectof active drug decreases with increasing placebo effect. This indicates thateffects of placebo and active intervention may not be simply additive, and weneed to quantify placebo effect which can be best done when compared tono-treatment. It would be unethical to recruit no-treatment group in diseasedconditions. It has been evidenced earlier that deceptive administration ofplacebo simulated clinical situations in that subjects were led to believe thatthey were receiving an active drug. In contrast, subjects in double-blindconditions were aware that they might receive a placebo. Double-blind anddeceptive administration of the placebo produced different results in studiesof mood, blood pressure and heart rate. However, placebo compared tono-treatment has not been studied. Moreover, response to reward mechanisms of placebo effect may bedifferent in healthy and diseased states. Thus, this study has been planned tostudy and measure the true effects of placebo in healthy human volunteers.