Seetal Dodd1, Olivia M Dean2, João Vian3, Michael Berk4. 1. Deakin University, IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, The University of Melbourne, Parkville, Victoria, Australia; The Centre for Youth Mental Health, Parkville, Victoria, Australia. Electronic address: seetald@barwonhealth.org.au. 2. Deakin University, IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, The University of Melbourne, Parkville, Victoria, Australia; The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia. 3. Psychiatry and Mental Health Department, Centro Hospitalar Lisboa Norte, Lisbon, Portugal; Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal. 4. Deakin University, IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, The University of Melbourne, Parkville, Victoria, Australia; The Centre for Youth Mental Health, Parkville, Victoria, Australia; The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia.
Abstract
PURPOSE: Placebos are commonly used in experimental and patient populations and are known to influence treatment outcomes. The mechanism of action of placebos has been investigated by several researchers. This review investigates the current knowledge regarding the theoretical and biological underpinning of the nocebo and placebo phenomena. METHOD: Literature was searched using PubMed using the following keywords: nocebo, placebo, μ-opioid, dopamine, conditioning, and expectancy. Relevant papers were selected for review by the authors. FINDINGS: The roles of conditioning and expectancy, and characteristics associated with nocebo and placebo responses, are discussed. These factors affect nocebo and placebo responses, although their effect sizes vary greatly, depending on inter-individual differences and different experimental paradigms. The neurobiology of the nocebo and placebo phenomena is also reviewed, emphasizing the involvement of reward pathways, such as the μ-opioid and dopamine pathways. Neurobiological pathways have been investigated in a limited range of experimental paradigms, with the greatest efforts on experimental models of placebo analgesia. The interconnectedness of psychological and physiological drivers of nocebo and placebo responses is a core feature of these phenomena. IMPLICATIONS: Further research is needed to fully understand the underpinnings of the nocebo and placebo phenomena. Neurobiology pathways need to be investigated in experimental paradigms that model the placebo response to a broader range of pathologies. Similarly, although many psychological factors and inter-individual characteristics have been identified as significant mediators and moderators of nocebo and placebo responses, the factors identified to date are unlikely to be exhaustive.
PURPOSE: Placebos are commonly used in experimental and patient populations and are known to influence treatment outcomes. The mechanism of action of placebos has been investigated by several researchers. This review investigates the current knowledge regarding the theoretical and biological underpinning of the nocebo and placebo phenomena. METHOD: Literature was searched using PubMed using the following keywords: nocebo, placebo, μ-opioid, dopamine, conditioning, and expectancy. Relevant papers were selected for review by the authors. FINDINGS: The roles of conditioning and expectancy, and characteristics associated with nocebo and placebo responses, are discussed. These factors affect nocebo and placebo responses, although their effect sizes vary greatly, depending on inter-individual differences and different experimental paradigms. The neurobiology of the nocebo and placebo phenomena is also reviewed, emphasizing the involvement of reward pathways, such as the μ-opioid and dopamine pathways. Neurobiological pathways have been investigated in a limited range of experimental paradigms, with the greatest efforts on experimental models of placebo analgesia. The interconnectedness of psychological and physiological drivers of nocebo and placebo responses is a core feature of these phenomena. IMPLICATIONS: Further research is needed to fully understand the underpinnings of the nocebo and placebo phenomena. Neurobiology pathways need to be investigated in experimental paradigms that model the placebo response to a broader range of pathologies. Similarly, although many psychological factors and inter-individual characteristics have been identified as significant mediators and moderators of nocebo and placebo responses, the factors identified to date are unlikely to be exhaustive.
Authors: Gianluca Castelnuovo; Emanuele Maria Giusti; Gian Mauro Manzoni; Donatella Saviola; Samantha Gabrielli; Marco Lacerenza; Giada Pietrabissa; Roberto Cattivelli; Chiara Anna Maria Spatola; Alessandro Rossi; Giorgia Varallo; Margherita Novelli; Valentina Villa; Francesca Luzzati; Andrea Cottini; Carlo Lai; Eleonora Volpato; Cesare Cavalera; Francesco Pagnini; Valentina Tesio; Lorys Castelli; Mario Tavola; Riccardo Torta; Marco Arreghini; Loredana Zanini; Amelia Brunani; Ionathan Seitanidis; Giuseppe Ventura; Paolo Capodaglio; Guido Edoardo D'Aniello; Federica Scarpina; Andrea Brioschi; Matteo Bigoni; Lorenzo Priano; Alessandro Mauro; Giuseppe Riva; Daniele Di Lernia; Claudia Repetto; Camillo Regalia; Enrico Molinari; Paolo Notaro; Stefano Paolucci; Giorgio Sandrini; Susan Simpson; Brenda Kay Wiederhold; Santino Gaudio; Jeffrey B Jackson; Stefano Tamburin; Fabrizio Benedetti Journal: Front Neurol Date: 2018-05-18 Impact factor: 4.003
Authors: Alan E Kazdin; Adam Glick; Jennifer Pope; Ted J Kaptchuk; Bernadette Lecza; Erin Carrubba; Emily McWhinney; Natasha Hamilton Journal: Int J Clin Health Psychol Date: 2018-02-07