The association of placebo effects with RCTs has caused confusion because the response in the placebo arm is not necessarily a genuine psychosocial response to the simulation of treatment. In fact, the observed response to placebo in RCTs may reflect natural course of disease, fluctuations in symptoms, regression to the mean, response bias with respect to the patient reporting of subjective symptoms and other concurrent treatments. Furthermore, a traditional focus on the “inert” content of a placebo has led to difficulties in defining and understanding placebo effects (7
), let alone applying them in a clinical research and practice (9
Much of the controversy surrounding placebo effects relates to how they are conceptualized and then defined. Generally, a placebo is seen as an inert substance or procedure and the placebo effect (or response) is something that follows administration of a placebo. The paradox in this statement lies with the fact that if something is “inert’, it by definition is unable to elicit an effect, and therefore placebos can't elicit placebo effects (7
). This can be further confused with terminology such as “active” (10
), “true” and “perceived” placebos (11
), which are all attempts to better conceptualise placebo effects, and other terms such as context effects (12
) and meaning responses (7
) which have shifted the focus from the use of the word. Nevertheless, the “placebo” terminology, despite its defects, is too engrained in the scientific literature to replace it at this time, especially in the absence of a satisfactory alternative.
To obviate these confusions and better understand placebo effects in clinical trials and practice, it is necessary to reconceptualise placebos and placebo effects, shifting the focus from the “inert” content of a placebo or sham procedure to what the placebo intervention, consisting of a simulated treatment and the surrounding clinical context is actually doing to the patient. Accumulated evidence indicates that the placebo effect is a genuine psychobiological phenomenon attributable to the overall therapeutic context (9
). This psychosocial context surrounding the patient can be comprised of both individual patient and clinician factors, and the interaction between the patient, clinician and treatment environment. The latter represents the many factors involved in a treatment context (such as the specific nature of the treatment and the way it is administered) and the “Doctor-Patient Relationship”, which is a term that encompasses a host of factors that constitute the therapeutic interaction ()(12
). The placebo intervention is designed to simulate a therapeutic context such that the effect following this intervention, the placebo effect, is attributable to the way in which this context affects the patient brain, body and behaviour (9
). When an active treatment is given, the overall response is the result of the treatment itself and the context in which it is given. Such a conceptualization allows for progression in thinking about the many factors which make up the psychosocial context around a patient and how these factors, and the mechanisms by which they operate can be enhanced in clinical practice.
Contributions of the psychosocial context surrounding the patient (or placebo component of a given therapy) to the overall response