What Is the Role of the Placebo Effect for Pain Relief in Neurorehabilitation? Clinical Implications From the Italian Consensus Conference on Pain in Neurorehabilitation.

Gianluca Castelnuovo,Enrico Molinari,Gian Mauro Manzoni,Giuseppe Riva,Federica Scarpina,Lorenzo Priano,Matteo Bigoni,Ionathan Seitanidis,Giorgia Varallo,Andrea Brioschi,Stefano Tamburin,Guido Edoardo D’Aniello,Alessandro Mauro,Amelia Brunani,Fabrizio Benedetti,Santino Gaudio,Camillo Regalia,Susan Simpson,Paolo Notaro,Margherita Novelli,Mario Tavola,Riccardo Torta,Valentina Tesio,Carlo Lai,Giorgio Sandrini,Emanuele Maria Giusti,Eleonora Volpato,Lorys Castelli,Stefano Paolucci,Roberto Cattivelli,Claudia Repetto,Daniele Di Lernia,Donatella Saviola,Francesca Luzzati,Alessandro Rossi,Francesco Pagnini,Giada Pietrabissa,Valentina Villa,Marco Arreghini,Loredana Zanini,Marco Lacerenza,Andrea Cottini,Paolo Capodaglio,Giuseppe Ventura,Samantha Gabrielli,Cesare Cavalera,Brenda K Wiederhold ,Jean Jackson ,Chiara A M Spatola

doi:10.3389/fneur.2018.00310

Abstract

It is increasingly acknowledged that the outcomes of medical treatments are influenced by the context of the clinical encounter through the mechanisms of the placebo effect. The phenomenon of placebo analgesia might be exploited to maximize the efficacy of neurorehabilitation treatments. Since its intensity varies across neurological disorders, the Italian Consensus Conference on Pain in Neurorehabilitation (ICCP) summarized the studies on this field to provide guidance on its use. A review of the existing reviews and meta-analyses was performed to assess the magnitude of the placebo effect in disorders that may undergo neurorehabilitation treatment. The search was performed on Pubmed using placebo, pain, and the names of neurological disorders as keywords. Methodological quality was assessed using a pre-existing checklist. Data about the magnitude of the placebo effect were extracted from the included reviews and were commented in a narrative form. 11 articles were included in this review. Placebo treatments showed weak effects in central neuropathic pain (pain reduction from 0.44 to 0.66 on a 0-10 scale) and moderate effects in postherpetic neuralgia (1.16), in diabetic peripheral neuropathy (1.45), and in pain associated to HIV (1.82). Moderate effects were also found on pain due to fibromyalgia and migraine; only weak short-term effects were found in complex regional pain syndrome. Confounding variables might have influenced these results. These estimates should be interpreted with caution, but underscore that the placebo effect can be exploited in neurorehabilitation programs. It is not necessary to conceal its use from the patient. Knowledge of placebo mechanisms can be used to shape the doctor-patient relationship, to reduce the use of analgesic drugs and to train the patient to become an active agent of the therapy.

Highlights

The placebo effect can be defined as the improvement in the patient’s symptoms after the administration of an inert substance in a context inducing positive expectations about its effects [1, 2]
The placebo response can be considered as a form of contextual healing, since the beneficial outcome is due to the context of the clinical encounter, rather than to a specific efficacy of the actual treatment [7,8,9]
A review of the existing reviews and meta-analyses examining the role of the placebo effect in disorders that may undergo neurorehabilitation treatment was performed

Summary

Introduction

The placebo effect can be defined as the improvement in the patient’s symptoms after the administration of an inert substance in a context inducing positive expectations about its effects [1, 2] This phenomenon is raising a growing interest in the field of pain management in patients with neurological disorders. Neurorehabilitation treatments could be delayed or hampered by pain symptoms, whose management could be difficult since the available treatments may provide only a moderate relief at the cost of various undesirable side effects [3,4,5] In this context, knowledge of the mechanisms of the placebo effect could be important. Since its intensity varies across neurological disorders, the Italian Consensus Conference on Pain in Neurorehabilitation (ICCP) summarized the studies on this field to provide guidance on its use.

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Results