An alternate opinion attributes the false perception of a placebo effect to the fact that patients who have been given a placebo report improvement earlier and more eagerly in order to please and thank the care giver. These patients may even do this when there is no real physical improvement attained. One quoted figure is that about one third of patients improve on a placebo, but a recent study has called that number into question. Hróbjartsson and Götzsche reported in 2001 that the placebo effect is much smaller than previously thought, if it exists at all. The 30 percent figure derives from a paper by Henry Beecher, published in 1955 (H. Beecher, 1955). Beecher was one of the leading advocates of the need to evaluate treatments by means of double-blind trials and this helps to explain why it has been so widely quoted.
The Hróbjartsson & Götzsche study demonstrated that in many studies where a control group was used that did not get any treatment at all, the effects in the no-treatment group were almost equal to the effects in the placebo group for studies with binary outcomes (e. g. well treated or poorly treated). The authors concluded that the placebo effect does not have "powerful clinical effects," and conceded that placebos have "possible small benefits in studies with continuous subjective outcomes and for the treatment of pain." They therefore concluded that there was no justification for its use outside of clinical trials.
In a follow-up study in 2004. the same authors were able to confirm their previous results and concluded: "We found no evidence of a generally large effect of placebo interventions. A possible small effect on patient-reported continuous outcomes, especially pain, could not be clearly distinguished from bias " .
If their conclusions are correct, the placebo effect is reduced to a subjective placebo illusion. while retaining its importance as a statistical research tool. As such it is imperative to use it in research, but unethical to use it in normal clinical treatment of patients.
These conclusions contradict what some would now consider to be a great deal of folklore that has evolved around the whole idea of the placebo effect. That folklore has evolved in a "research vacuum" of ignorance about the true nature of the placebo effect.
What is new about these conclusions is an emphasis on the key words "subjective" and "pain". This explains the well-established fact that the placebo effect is most "effective" in conditions where subjective factors are very prominent or significant parts of the problem. Some of these conditions are: headache, stomach ache, asthma, allergy, tension, and especially the most subjective of them all - pain, which is a significant part of most serious (and many mild) illnesses.
It also explains why there is no conclusive documentation for placebos causing significant healing effects in serious biological pathologies.
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