Placebo Effect Redefined as Part of Effective Treatment

A new study suggests that using the placebo effect could improve treatment for several chronic diseases that involve mental state or the immune system, including psoriasis, asthma, multiple sclerosis, and chronic pain.

Researchers at the University of Rochester Medical Center (URMC; NY, USA), Stanford University (CA, USA), and Harvard University Medical School (Cambridge, MA, USA) conducted an 11 to 14-week, double blind, randomized clinical trial in 46 patients with mild-to-moderate psoriasis. The patients signed consent forms after being informed they might receive a reduced dose of topical steroid, and were on no other medications during the study. Initially, the lesions were treated with 0.1% acetonide triamcinolone under standard treatment conditions. After the three-week baseline period, the patients were randomly assigned to one of three groups; the first continued to receive 100% percent of the treatment drug; a second partial reinforcement group also continued to receive a full dose, but only 25% or 50% of the time, and a steroid-free emollient the rest of the time. A third dose control group received active drug at every administration, but at 25% or 50% of the full dose used in the first and second groups.

The results showed that the severity of disease scores in Stanford neither supported nor refuted the hypothesis that psoriasis patients treated under a partial schedule of pharmacologic reinforcement would show less severe symptoms and relapse than those given the same amount of drug under standard conditions. In URMC--where there was no difference between partial reinforcement and dose control groups at baseline--partial reinforcement effected a greater reduction in lesion severity than dose control conditions, and did not differ from standard therapy patients receiving the full dose. For the total population, the frequency of relapse under partial reinforcement (26.7%) was lower than in dose control patients (61.5%), and did not differ substantially from full-dose treatment (22.2%). The study was published ahead of print on December 22, 2009, in the journal Psychosomatic Medicine.

"Our study provides evidence that the placebo effect can make possible the treatment of psoriasis with an amount of drug that should be too small to work,” said lead author professor of psychiatry Robert Ader, Ph.D., M.D. "While these results are preliminary, we believe the medical establishment needs to recognize the mind's reaction to medication as a powerful part of many drug effects, and start taking advantage of it.”

A placebo (Latin for "I shall please") is a pharmacologically inert substance or procedure that produces an effect that is the measurable, observable, or felt in health or behavior that is not attributable to the medication or any invasive treatment administered. The exact physiological mechanisms remain mysterious. Some of the theories that attempt to explain the placebo effect include self-limiting disorders that resolve by themselves anyway, coincidental remission, increased motivation, altered perception of symptoms that change with the expectation of feeling better, reduced anxiety that reduces the levels of stress chemicals (such as adrenaline), or the release of the body's own natural painkillers, known as endorphins.

Related Links:
University of Rochester Medical Center
Stanford University
Harvard University Medical School