The placebo effect in asthma: Far more complex than simply 'I shall please'.

摘要

The randomized, double-blind, placebo-controlled clinical trial is the gold standard by which efficacy, safety, and even mechanisms of action of treatments are evaluated and established. In the planning of clinical trials in asthma, it is anticipated that a placebo effect will occur and may often influence the interpretations of the outcomes or the perceived overall effectiveness of the treatment. Consequently, considerable effort is expended in the planning and design of a clinical trial. For example, entry criteria for recruited patients are often established to minimize the erirollment of subjects with characteristics that might promote"^placebo effect or to avoid the selection of individuals who might be prone to a significant placebo effect. As demonstrated by the study of Robert Wise1 and the American Lung Association Asthma Clinical Research Centers coinvestigators published in this issue of the Journal, placebo effects do indeed occur in asthma studies, but the effect of a placebo is not seen on all outcomes or under all conditions. From our perspective, the investigation by Wise et al1 to assess, understand, and interpret more precisely the complexity of the placebo response will be helpful for Journal readers. Their observations should help asthma caregivers appreciate more comprehensively the placebo phenomenon in asthma clinical trials and the possible neuromechanisms involved in the participant's response to treatment.