MDD The Mysterious Placebo Effect

Understanding it can help avoid flawed study designs.
BY CAROL HART
Mandrake root, powdered mummy, comb, spider web, ants, scorpions, bone, teeth, crab’s eyes, viper’s flesh, worms, and pearls. These are just a few of the ingredients from the premodern pharmacopoeia, some of which were still in use at the turn of the century. No one would question the fact that they worked as a placebo, if at all. But how many drugs in our current pharmacopoeia also might be ineffective? We rely on double-blind placebo-controlled trials to tell us, but the answers may not always hold true with clinical experience.
The word placebo (“I will please” in Latin) entered the English language by way of a peculiar mistranslation of the 116th Psalm that read, “I will please the Lord” rather than “I will walk before the Lord”. In the medieval Catholic liturgy, this verse opened the Vespers for the Dead; because professional mourners were sometimes hired to sing vespers, “to sing placebos” came to be a derogatory phrase describing a servile flatterer. By the early 19th century, “placebo” had come to mean a medicine given “more to please than to benefit the patient” (1).
Outside the context of modern clinical trials, “placebo” has been a term reserved for characterizing the substandard practices of other less ethical or knowledgeable healers, if not outright quacks and frauds. Few doctors admit to knowingly using placebos (1). In fact, some off-label uses or suboptimal dosing of active medication may act only as a placebo, and the much-criticized but common practice of prescribing antibiotics for viral colds and flu is evidence that use of placebos still flourishes in contemporary medicine (2).
In recent decades, the reputation of placebos as a deceitful fraud has undergone considerable reconstruction. To alternative medicine practitioners, placebo response represents the mysterious self-healing forces generated by the mind–body connection. Mainstream physicians now urge their colleagues to make more effective use of placebo-based healing by more empathic and attentive interactions with their patients (3). Researchers still may be inclined to view placebo effects as a nuisance or as a background noise that complicates clinical trial design. Understanding the basis of placebo effects, however, can help in filtering out noise and avoiding flawed study designs.

MDD July/August 1999: The Mysterious Placebo Effect