Mechanisms and clinical implications of the placebo effect: is there a potential for the elderly? A mini-review

Abstract

In recent years, the placebo effect has been a topic of considerable interest both in the scientific and the clinical community. In this time, the placebo effect has evolved from being considered a nuisance in clinical and pharmacological research to becoming a neurobiological phenomenon worthy of scientific investigation in its own right. Recent research shows that placebo effects are genuine psychobiological events attributable to the overall therapeutic context, and that these effects can be robust in both laboratory and clinical settings. These psychosocially induced biochemical changes in a patient's brain and body may in turn affect the course of a disease and the response to a therapy. Here we summarize and discuss the current insights into placebo mechanisms and discuss the potentially widespread implications for research and clinical practice. Even though a systematic knowledge of placebo effects across the lifespan is lacking, we aim at highlighting specific aspects related to the care of elderly patients and those suffering from neurodegenerative diseases.

Fig. 1

Psychosocial context producing a placebo response. Left: Individual patient and clinician factors promoting the formation of a placebo response. Right: The treatment per se, the doctorpatient relationship and the treatment environment (e.g. therapeutic procedure, method of drug administration, technological devices) modulate the mind-body unit. Although speculative, genetic variability may influence the final outcome. Thus, individual, contextual and genetic factors interact with each other and determine the overall clinical placebo response.

Fig. 2

Impairment of placebo component in AD patients. Note the difference between normal subjects (on the left) and AD patients (on the right) as shown by electroencephalographic mutual information connectivity analysis, cognitive status assessed by means of frontal assessment battery (FAB), and pain reduction following the application of analgesic lidocaine according to the open-hidden paradigm. Note the difference between the connectivity peaks in a normal subject (top on the left) and an AD patient (top on the right). In AD patients, there was a reduction of brain connectivity, FAB scores, and psychosocial placebo component of the active medication. Modified from Colloca et al. [62]; data from Benedetti et al. [35].