The role of expectancies in the placebo effect and their use in the delivery of health care: a systematic review.

Abstract

T he overall aim of the NHS R&D Health Technology Assessment (HTA) programme is to ensure that high-quality research information on the costs, effectiveness and broader impact of health technologies is produced in the most efficient way for those who use, manage and work in the NHS. Research is undertaken in those areas where the evidence will lead to the greatest benefits to patients, either through improved patient outcomes or the most efficient use of NHS resources. The Standing Group on Health Technology advises on national priorities for health technology assessment. Six advisory panels assist the Standing Group in identifying and prioritising projects. These priorities are then considered by the HTA Commissioning Board supported by the National Coordinating Centre for HTA (NCCHTA). This report is one of a series covering acute care, diagnostics and imaging, methodology, pharmaceuticals, population screening, and primary and community care. It was identified as a priority by the Methodology Panel and funded as project number 94/34/04. The views expressed in this publication are those of the authors and not necessarily those of the Standing Group, the Commissioning Board, the Panel members or the Department of Health. The editors wish to emphasise that funding and publication of this research by the NHS should not be taken as implicit support for the recommendations for policy contained herein. In particular, policy options in the area of screening will be considered by the National Screening Committee. This Committee, chaired by the Chief Medical Officer, will take into account the views expressed here, further available evidence and other relevant considerations. Reviews in Health Technology Assessment are termed 'systematic' when the account of the search, appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.

The Role of Patients’ Response Expectancies in Side Effect Development and Control

“…The expectancy on the part of the cancer patient that CAM will be effective is a very strong motivating factor that influence the decision to choose CAM. 12,160 The high rate of CAM use by cancer patients and the lay population is in sharp contrast to the generally reported low opinions of CAM efficacy held by physicians practicing conventional medicine. 161,162 Even though physician referral rates as high as 43% for acupuncture, 40% for massage, and 21% for chiropractic therapy have been reported, 163 in general, most physicians believe that CAM therapies are nothing more than placebo or expectancy effects 124,[164][165][166][167][168][169][170][171] There is still uncertainty as to whether or not treatment effects of CAM are direct or due to nonspecific factors, such as patient belief, expectations, and faith.…”

“…They reported that expectancies play an important role in symptom and side effect development and further concluded that response expectancies constitute a central underlying mechanism of placebo effect. 12 Other studies have reported significant relationships between patients' expectancies with reports of symptoms, and engagement in various life activities. [13][14][15][16][17][18][19][20] In addition, the role of response expectancies in symptom development is evident in experiments that revealed successful reduction in symptoms as a result of interventions that manipulated participants' response expectancies.…”

Applying evidence to support ethical decisions: Is the placebo really powerless?

“…Two reviews on the role of information provide some support for the mentioned placebo effect, but also identified the need for more research in this area. 33,34 The lack of solid data on the influence of information is not surprising, as it is rather difficult -according to ethical rules -to test the influence of information in a clinical trial. Such experiments require providing different information to otherwise identically-treated patients.…”

Klinische Bedeutung des Placeboeffektes

“…In 85 ausgewählten Veröffentlichungen, in de nen die Erwartungshaltung u. a. bezüg lich des Therapeuten ein primärer Unter suchungsparameter war, waren die Über zeugtheit von der Behandlung, selbst sicheres Auftreten, Autorität, Empathie und Herzlichkeit des Behandlers mit aus geprägteren Placeboeffekten assoziiert [33]. Weitere für den Placeboeffekt güns tige Therapeutenqualitäten scheinen Er fahrung, Sicherheit, Kommunikationsfä higkeiten, Art der Instruktionen und Zeit aufwand mit dem Patienten zu sein [65].…”

“…B. EKG) können bei Patienten mit unspezi fischen Brustschmerzen im Vergleich zu einer Gruppe, die diese Diagnostik nicht erhält, zur Verbesserung der Symptome führen [114]. Patienten, die eine höhere Erwartung an ihre Eigenkompetenz bei spielsweise durch erlernte Entspannungs techniken haben, zeigen bei chronischen Schmerzsyndromen oder bei schmerz haften medizinischen Eingriffen ausge prägtere Placeboeffekte [33]. Patienten, die prä und postoperative Instruktionen erfahren, benötigen postoperativ weniger Analgetika und werden früher entlassen [42].…”