Hidden Administration of Drugs

Opioidergic activation of the descending pain inhibitory system underlies placebo analgesia

Placebo analgesia is caused by inactive treatment, implicating endogenous brain function involvement. However, the neurobiological basis remains unclear. In this study, we found that μ-opioid signals in the medial prefrontal cortex (mPFC) activate the descending pain inhibitory system to initiate placebo analgesia in neuropathic pain rats. Chemogenetic manipulation demonstrated that specific activation of μ-opioid receptor-positive (MOR+) neurons in the mPFC or suppression of the mPFC-ventrolateral periaqueductal gray (vlPAG) circuit inhibited placebo analgesia in rats. MOR+ neurons in the mPFC are monosynaptically connected and directly inhibit layer V pyramidal neurons that project to the vlPAG via GABAA receptors. Thus, intrinsic opioid signaling in the mPFC disinhibits excitatory outflow to the vlPAG by suppressing MOR+ neurons, leading to descending pain inhibitory system activation that initiates placebo analgesia. Our results shed light on the fundamental neurobiological mechanism of the placebo effect that maximizes therapeutic efficacy and reduces adverse drug effects in medical practice.

The expectations humans have of a pleasurable sensation asymmetrically shape neuronal responses and subjective experiences to hot sauce

Expectations shape our perception, profoundly influencing how we interpret the world. Positive expectations about sensory stimuli can alleviate distress and reduce pain (e.g., placebo effect), while negative expectations may heighten anxiety and exacerbate pain (e.g., nocebo effect). To investigate the impact of the (an)hedonic aspect of expectations on subjective experiences, we measured neurobehavioral responses to the taste of hot sauce among participants with heterogeneous taste preferences. By identifying participants who "liked" versus those who strongly "disliked" spicy flavors and by providing contextual cues about the spiciness of the sauce to be tasted, we dissociated the effects of positive and negative expectations from sensory stimuli (i.e., visual and gustatory stimuli), which were the same across all participants. Our results indicate that positive expectations lead to modulations in the intensity of subjective experience. These modulations were accompanied by increased activity in brain regions previously linked to information integration and the placebo effect, including the anterior insula, dorsolateral prefrontal cortex, and dorsal anterior cingulate cortex, as well as a predefined "pleasure signature." In contrast, negative expectations decreased hedonic experience and increased neural activity in the previously validated "Neurological Pain Signature" network. These findings demonstrate that hedonic aspects of one's expectations asymmetrically shape how the brain processes sensory input and associated behavioral reports of one's subjective experiences of intensity, pleasure, and pain. Our results suggest a dissociable impact of hedonic information: positive expectations facilitate higher-level information integration and reward processing, while negative expectations prime lower-level nociceptive and affective processes. This study demonstrates the powerful role of hedonic expectations in shaping subjective reality and suggests potential avenues for consumer and therapeutic interventions targeting expectation-driven neural processes.

Creating Placebo Nonresponders in the Lab

Conditioning and expectation are known to be the main mechanisms of placebo analgesia. They may operate together, so that expectations may be enhanced by a conditioning procedure. Although most of the studies have tried to potentiate expectations through conditioning in order to generate good placebo responders, a few studies have tried to mismatch conditioning and expectations in order to investigate the subsequent administration of a placebo. In this study, we want to further investigate this mismatch. We generated incongruent associations during a conditioning procedure in which the study participants did not get what they expected. In fact, although the participants received verbal instructions of pain decrease following the administration of a placebo, we surreptitiously increased the painful electric stimulation. Two pairings of these incongruent associations (mismatch between what was expected and what was experienced) disrupted expectations of analgesia as well as the placebo effect, as assessed by measuring electric pain thresholds on the hand. The effects of mismatch conditioning on the hand extended to the contralateral arm and to a different type of pain (tourniquet), which suggests that local mismatch conditioning may affect the whole body. In all cases, expectations predicted placebo analgesia. These findings indicate that placebo nonresponders can be created in the laboratory by acting on expectations and that local effects can be generalized to other parts of the body. They also stress the importance of expectations in the therapeutic outcome, with important implications for clinical trials. PERSPECTIVE: By using mismatch conditioning, in which study participants did not get what they expected, we reduced expectations of analgesia, and this reduction abolished placebo analgesia. This effect extended to other parts of the body and other types of pain, which indicates that placebo nonresponders can be created in the laboratory.

Harnessing placebo: Lessons from psychedelic science

The randomized controlled trial (RCT) research design assumes that a drug's "specific" effect can be isolated, added, and subtracted from the "nonspecific" effect of context and person. While RCTs are helpful in assessing the added benefit of a novel drug, they tend to obscure the curative potential of extra-pharmacological variables, known as "the placebo effect." Ample empirical evidence suggests that person/context-dependent physical, social, and cultural variables not only add to, but also shape drug effects, making them worth harnessing for patient benefits. Nevertheless, utilizing placebo effects in medicine is challenging due to conceptual and normative obstacles. In this article, we propose a new framework inspired by the field of psychedelic science and its employment of the "set and setting" concept. This framework acknowledges that drug and nondrug factors have an interactive and synergistic relationship. From it, we suggest ways to reintegrate nondrug variables into the biomedical toolbox, to ethically harness the placebo effect for improved clinical care.

The Biology of Placebo and Nocebo Effects on Experimental and Chronic Pain: State of the Art

(1) Background: In recent years, placebo and nocebo effects have been extensively documented in different medical conditions, including pain. The scientific literature has provided strong evidence of how the psychosocial context accompanying the treatment administration can influence the therapeutic outcome positively (placebo effects) or negatively (nocebo effects). (2) Methods: This state-of-the-art paper aims to provide an updated overview of placebo and nocebo effects on pain. (3) Results: The most common study designs, the psychological mechanisms, and neurobiological/genetic determinants of these phenomena are discussed, focusing on the differences between positive and negative context effects on pain in experimental settings on healthy volunteers and in clinical settings on chronic pain patients. Finally, the last section describes the implications for clinical and research practice to maximize the medical and scientific routine and correctly interpret the results of research studies on placebo and nocebo effects. (4) Conclusions: While studies on healthy participants seem consistent and provide a clear picture of how the brain reacts to the context, there are no unique results of the occurrence and magnitude of placebo and nocebo effects in chronic pain patients, mainly due to the heterogeneity of pain. This opens up the need for future studies on the topic.

‘It's not my greengrocer, it's someone from the medical profession’: A qualitative study regarding acceptability of deceptive and open‐label placebo prescribing in France

OBJECTIVES

To explore participants' views regarding clinical use of deceptive placebo (DP) and open-label placebo (OLP) treatments.

DESIGN

Qualitative thematic analysis.

METHODS

We conducted eight semi-structured interviews with healthy participants in an experimental trial comparing the efficacy of OLP and DP (Clinical trials n°NCT03934138). Interviewees' opinions were solicited following administration of placebos during the trial. Interviews were analysed using data-driven analysis.

RESULTS

We identified three themes. First, participants considered trust central in judging a placebo treatment to be acceptable. They expressed the importance of an implicit trust both in their health care professionals' (HCPs') competency as well as in the profession at large. A second theme was the perception of how placebo treatments might solve health problems. Acceptability of both types of placebo treatments was dependent on the perception patients had about the treatment solving their problem and/or doubts regarding the effectiveness of placebos The third theme encompassed perceived risks associated with placebo prescribing. Some comments viewed placebos positively as facilitating reduced medication intake. However, participants also identified the potential of placebos to generate adverse side effects.

CONCLUSIONS

Treatment acceptability by patients is a pre-requisite, alongside effectiveness, to harness OLPs in clinical care. Our study identified the importance of trust in HCPs prescribing placebos, the clinical effectiveness of placebos and the potential risks of these interventions in assessing their acceptability. Future research is needed to explore the contexts in which placebos might be used, and how best to communicate information about placebo interventions.

Placebo effects and neuromodulation for depression: a meta-analysis and evaluation of shared mechanisms

There is growing evidence that placebo effects can meaningfully modulate the brain. However, there has been little consideration of whether these changes may overlap with regions/circuits targeted by depression treatments and what the implications of this overlap would be on measuring efficacy in placebo-controlled clinical trials. In this systematic review and meta-analysis, we searched PubMed/Medline and Google Scholar for functional MRI and PET neuroimaging studies of placebo effects. Studies recruiting both healthy subjects and patient populations were included. Neuroimaging coordinates were extracted and included for Activation Likelihood Estimation (ALE) meta-analysis. We then searched for interventional studies of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS) for depression and extracted target coordinates for comparative spatial analysis with the placebo effects maps. Of 1169 articles identified, 34 neuroimaging studies of placebo effects were included. There were three significant clusters of activation: left dorsolateral prefrontal cortex (DLPFC) (x = -41, y = 16, z = 34), left sub-genual anterior cingulate cortex (sgACC)/ventral striatum (x = -8, y = 18, z = -15) and the right rostral anterior cingulate cortex (rACC) (x = 4, y = 42, z = 10). There were two significant deactivation clusters: right basal ganglia (x = 20, y = 2, z = 7) and right dorsal anterior cingulate cortex (dACC) (x = 1, y = -5, z = 45). TMS and DBS targets for depression treatment overlapped with the left DLPFC cluster and sgACC cluster, respectively. Our findings identify a common set of brain regions implicated in placebo effects across healthy individuals and patient populations, and provide evidence that these regions overlap with depression treatment targets. We model the statistical impacts of this overlap and demonstrate critical implications on measurements of clinical trial efficacy for this field.

What is the role of placebo in neurotherapeutics?

INTRODUCTION

The widespread use of the word 'placebo' in the medical literature emphasizes the importance of this phenomenon in modern biomedical sciences. Neuroscientific research over the past thirty years shows that placebo effects are genuine psychobiological events attributable to the overall therapeutic context, and can be robust in both laboratory and clinical settings.

AREAS COVERED

Here the authors describe the biological mechanisms and the clinical implications of placebo effects with particular emphasis on neurology and psychiatry, for example in pain, movement disorders, depression. In these conditions, a number of endogenous systems have been identified, such as endogenous opioids, endocannabinoids, and dopamine, which contribute to the placebo-induced benefit.

EXPERT OPINION

Every effort should be made to maximize the placebo effect and reduce its evil twin, the nocebo effect, in medical practice. This does not require the administration of a placebo, but rather the enhancement of the effects of pharmacological and nonpharmacological treatments through a good doctor-patient interaction.

Consciousness in active inference: Deep self-models, other minds, and the challenge of psychedelic-induced ego-dissolution

Predictive processing approaches to brain function are increasingly delivering promise for illuminating the computational underpinnings of a wide range of phenomenological states. It remains unclear, however, whether predictive processing is equipped to accommodate a theory of consciousness itself. Furthermore, objectors have argued that without specification of the core computational mechanisms of consciousness, predictive processing is unable to inform the attribution of consciousness to other non-human (biological and artificial) systems. In this paper, I argue that an account of consciousness in the predictive brain is within reach via recent accounts of phenomenal self-modelling in the active inference framework. The central claim here is that phenomenal consciousness is underpinned by 'subjective valuation'-a deep inference about the precision or 'predictability' of the self-evidencing ('fitness-promoting') outcomes of action. Based on this account, I argue that this approach can critically inform the distribution of experience in other systems, paying particular attention to the complex sensory attenuation mechanisms associated with deep self-models. I then consider an objection to the account: several recent papers argue that theories of consciousness that invoke self-consciousness as constitutive or necessary for consciousness are undermined by states (or traits) of 'selflessness'; in particular the 'totally selfless' states of ego-dissolution occasioned by psychedelic drugs. Drawing on existing work that accounts for psychedelic-induced ego-dissolution in the active inference framework, I argue that these states do not threaten to undermine an active inference theory of consciousness. Instead, these accounts corroborate the view that subjective valuation is the constitutive facet of experience, and they highlight the potential of psychedelic research to inform consciousness science, computational psychiatry and computational phenomenology.

Thirty Years of Neuroscientific Investigation of Placebo and Nocebo: The Interesting, the Good, and the Bad

Over the past 30 years there has been a surge of research on the placebo effect using a neuroscientific approach. The interesting aspects of this effort are related to the identification of several biological mechanisms of both the placebo and nocebo effects, the latter of which is defined as a negative placebo effect. Some important translational implications have emerged both in the setting of clinical trials and in routine medical practice. One of the principal contributions of neuroscience has been to draw the attention of the scientific and medical communities to the important role of psychobiological factors in therapeutic outcomes, be they drug related or not. Indeed, many biological mechanisms triggered by placebos and nocebos resemble those modulated by drugs, suggesting a possible interaction between psychological factors and drug action. Unfortunately, this new knowledge regarding placebos has the potential of being dangerously exploited by pseudoscience. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Targeted Use of Placebo Effects Decreases Experimental Itch in Atopic Dermatitis Patients: A Randomized Controlled Trial

Evidence from pain research shows that the effectiveness of active pharmacological treatments can be enhanced by placebo effects. The "open drug administration" is superior to "hidden drug administration.​" In a randomized controlled trial, we aimed to show that the targeted use of placebo effects increases the efficacy of an antihistamine (dimetindene) infusion in participants with atopic dermatitis. We openly infused dimetindene (drug) in full sight with information (intervention group 1: OPEN-DRUG+INST), openly infused drug with an additional classical conditioning learning experience (intervention group 2: OPEN-DRUG+INST+COND) or infused drug without any information or sight (i.e., hidden administration (control group 1: HIDDEN-DRUG)). Control group 2 received a placebo infusion (saline) declared as dimetindene and also experienced the conditioning experience (PLAC+INST+COND). Itch was experimentally induced with histamine via a skin prick test. Outcome was assessed at the subjective (primary end point: experimental itch intensity, numeric rating scale), and objective level (secondary end point: wheal size, mm² ). Experimental-induced itch intensity decreased in all groups but at different rates (P < 0.001). The groups with the open administration, whether it was dimetindene or placebo, had significantly stronger reductions in itch compared to the HIDDEN-DRUG group (OPEN-DRUG+INST+COND: P < 0.001; OPEN-DRUG+INST: P = 0.009; and PLAC+INST+COND: P < 0.001). Additional drug conditioning mediated via expectation led to a stronger reduction of itching (P = 0.001). Results on wheal size were similar (P = 0.048), however, no significant difference between the HIDDEN-DRUG group and the PLAC+INST+COND group (P = 0.967) was found. We conclude that specifically generated targeted placebo effects can significantly increase the action of a drug (dimetindene) and should be used in clinical practice.

The subthalamic nucleus and the placebo effect in Parkinson's disease

The study of the placebo effect, or response, is related to the investigation of the psychologic component of different therapeutic rituals. The high rate of placebo responses in Parkinson's disease clinical trials provided the impetus for investigating the underlying mechanisms. Ruling out spontaneous remission and regression to the mean through the appropriate experimental designs, genuine psychologic placebo effects have been identified, in which both patients' expectations of therapeutic benefit and learning processes are involved. Specifically, placebo effects are associated with dopamine release in the striatum and changes in neuronal activity in the subthalamic nucleus, substantia nigra pars reticulata, and motor thalamus in Parkinson's disease, as assessed through positron emission tomography and single-neuron recording during deep brain stimulation, respectively. Conversely, verbal suggestions of clinical worsening or drug dose reduction induce nocebo responses in Parkinson's disease, which have been detected at both behavioral and electrophysiologic level. Important implications and applications emerge from this new knowledge. These include better clinical trial designs, whereby patients' expectations should always be assessed, as well as better drug dosage in order to reduce drug intake.

A virtual experimenter does not increase placebo hypoalgesia when delivering an interactive expectancy manipulation

Lack of standardization and unblinding threaten the research of mechanisms involved in expectancy effects on pain. We evaluated a computer-controlled virtual experimenter (VEx) to avoid these issues. Fifty-four subjects underwent a baseline-retest heat pain protocol. Between sessions, they received an expectancy manipulation (placebo or no-treatment) delivered by VEx or text-only control condition. The VEx provided standardized "social" interaction with the subjects. Pain ratings and psychological state/trait measures were recorded. We found an interaction of expectancy and delivery on pain improvement following the intervention. In the text conditions, placebo was followed by lower pain, whereas in the VEx conditions, placebo and no-treatment were followed by a comparable pain decrease. Secondary analyses indicated that this interaction was mirrored by decreases of negative mood and anxiety. Furthermore, changes in continuous pain were moderated by expectation of pain relief. However, retrospective pain ratings show an effect of expectancy but not of delivery. We conclude that we successfully applied an automated protocol for inducing expectancy effects on pain. The effect of the VEx regardless of treatment may be due to interactions of attention allocation and locus of control. This points to the diversity of expectancy mechanisms, and has implications for research and computer-based treatment applications.

The neurobiological underpinnings of placebo and nocebo effects

The placebo effect, once considered only a nuisance in clinical research, is today a target of scientific inquiry that allows us understand how words, rituals and, more in general, the whole psychosocial context around the patient, affect the response to a treatment and the course of a disease. Today we are in a good position to study all these complex psychological factors by using a physiological and neuroscientific approach that uses modern neurobiological tools to probe different brain functions. Since a placebo is represented by the whole ritual of the therapeutic act, the main concept that has emerged today is that words and rituals may modulate the same biochemical pathways that are modulated by drugs. Most of our knowledge about these mechanisms comes from the field of pain, and represents a biomedical, psychological and philosophical enterprise that is changing the way we approach and interpret medicine, psychology and human biology. If on the one hand we know some of the mechanisms of drug action in the central nervous system, on the other we can now understand how the clinician-patient interaction may affect different physiological functions. In fact, the placebo effect and the therapist-patient relationship can be approached by using the same biochemical, cellular and physiological tools of the materia medica. This represents an epochal transition, in which the distinction between drugs and words is progressively getting thinner, and which helps us overcome the old dichotomy between psychology and biology.

Maximizing placebo response in neurological clinical practice

The placebo effect is a widely recognized phenomenon in clinical research, with a negative perception that it could hide the "true" drug effect. In clinical care its positive potential to increase known drug effects has been neglected for too long. The placebo and nocebo responses have been described in many neurologic disorders such as Parkinson's, Huntington's and Alzheimer's diseases, restless leg syndrome, tics, essential tremor, dystonia, functional movement disorders, neuropathic pain, headaches, migraine, amyotrophic lateral sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis and epilepsy. Knowledge regarding placebo mechanisms and their consequences on clinical outcome have greatly improved over the last two decades. This evolution has led to reconsiderations of the importance of placebo response in the clinic and has given several clues on how to improve it in daily practice. In this chapter, we first illustrate "why," e.g. the reasons (relevance to clinical practice, help in differential diagnosis/treatment of psychogenic movements, clinical impact, proven neurobiological grounds, health economic potential), and "how," e.g. the means (increase patients' knowledge, increase learning, improve patient-doctor relationship, increase Hawthorne effect, increase positive/decrease negative expectations (the Rosenthal effect), personalize placebo response), the placebo should be maximized (and nocebo avoided) in neurological clinical practice. Future studies regarding more specific neurobiological mechanisms will allow a finer tuning of placebo response in clinical practice. The use of placebo in clinical practice raises ethical issues, and a recent expert consensus regarding placebo use in the clinic is a first step to future guidelines necessary to this field.

Understanding placebo and nocebo effects in the context of sport: A psychological perspective

Research over the past 15 years on the placebo effect has substantiated its contribution to the efficacy of established treatments for a range of clinical conditions and identified its underlying mechanisms. There is also evidence that placebo effects contribute to the performance benefits of many ergogenic aids, and that performance can worsen when dummy treatments are associated with expectations of a harmful outcome (i.e. nocebo effect). Unfortunately, the bulk of sport research involving placebos and nocebos continues to be hampered by outdated definitions and conceptualizations of placebo effects and their mechanisms. This has implications not only for research but also application, as nearly 50% of athletes report experiencing a beneficial placebo effect, and a similar proportion of coaches report providing placebos to their athletes. The objective of this paper is to attempt to stimulate research by presenting updated definitions of placebo and nocebo effects in the context of sport, describing their major mechanisms and, highlighting the importance of the psychosocial context on placebo effects in the sport setting.

"Placebo by Proxy" and "Nocebo by Proxy" in Children: A Review of Parents' Role in Treatment Outcomes

The "placebo (effect) by proxy" (PbP) concept, introduced by Grelotti and Kaptchuk (1), describes a positive effect of a patient's treatment on persons in their surrounding such as family members or healthcare providers, who feel better because the patient is being treated. The PbP effect is a complex dynamic phenomenon which attempts to explain a change in treatment outcome arising from an interaction between a patient and an effect from proxies such as parents, caregivers, physicians or even the media. By extension the effect of the proxy can also have a negative or adverse effect whereby a proxy feels worse when a patient is treated, giving rise to the possibility of a "nocebo (effect) by proxy" (NbP), and by extension can influence a patient's treatment response. While this has yet to be systematically investigated, such an effect could occur when a proxy observes that a treatment is ineffective or is perceived as causing adverse effects leading the patient to experience side effects. In this narrative review, we take these definitions one step further to include the impact of PbP/NbP as they transform to affect the treatment outcome for the patient or child being treated, not just the people surrounding the individual being treated. Following a systematic search of literature on the subject using the Journal of Interdisciplinary Placebo Studies (JIPS) database (https://jips.online) and PubMed (NCBI) resulted in very few relevant studies, especially in children. The effect of PbP per se has been studied in parents and their children for temper tantrums, acupuncture for postoperative symptoms, as well as for neuroprotection in very preterm-born infants. This paper will review the PbP/NbP concepts, show evidence for its presence in children's treatment outcome and introduce clinical implications. We will also offer suggestions for future research to further our understanding of the role of the proxy in promoting or distracting from treatment benefit in children. Increasing an appreciation of the PbP and NbP phenomena and the role of the proxy in children's treatment should improve research study design and ultimately harness them to improve clinical child healthcare.

Drug-Placebo Additivity in Randomized Clinical Trials

In randomized clinical trials (RCTs), it is assumed that nonspecific effects beyond action of pharmacological agents are roughly equivalent in drug and placebo treatment groups. Hence, since the inception of RCTs, drug efficacy is determined by comparing outcomes in active to those in placebo control arms. However, quantitation of efficacy is based on an unproven assumption, that drug and placebo responses are always additive. Response to treatment in RCTs can be differentially influenced by the perturbing effects of patient expectations, side effects, and pharmacogenomic interactions in both drug and placebo arms. Ability to control for these effects requires understanding of when and where they arise, how to mitigate, analyze, and even leverage their impact. Here, we examine three factors that influence additivity: expectation, side effects, and pharmacogenomics. Furthermore, to provide novel insights into nonadditivity and solutions for managing it, we introduce systems pharmacogenomics, a network approach to integrating and analyzing the effects of the numerous interacting perturbations to which a patient is exposed in RCTs.

Comparative Analgesia Between Acupuncture and Dipyrone in Odontalgia

The aim of this study was to assess whether the effectiveness of acupuncture is similar to the use of analgesics in the management of toothache. The research included 56 volunteers who were divided into 4 groups: Real Acupuncture group, Placebo Acupuncture group, Real Dipyrone group, and Placebo Dipyrone group. The interventions of the study were performed before the dental care. Inclusion criteria were toothache of pulpal origin with pain scale (Visual Analogue Scale) above 4, absence of medication for the pain, and aged over 18 years. The Real Acupuncture volunteers received a session of acupuncture using piercing needles, while volunteers from the Placebo Acupuncture group received an acupuncture session using non-piercing sham needles. Volunteers from the Real Dipyrone group received a dipyrone tablet and the Placebo Acupuncture group received a tablet with no active ingredient. Before any therapeutic intervention, we collected samples from the volunteers' saliva to analyze the salivary cortisol, the volunteers rated the intensity of their pain using VAS, and we measured their energy level by the Ryodoraku method. After 20 minutes of treatment, all the volunteers' analysis parameters were collected again. The Real Acupuncture group presented a greater reduction of VAS than the reduction obtained by the Real Dipyrone group (p<0.05). There was no statistically significant difference between the groups for the salivary cortisol and energy level variables. It can be concluded that acupuncture was more effective in reducing odontalgia than the dipyrone and that it can be an alternative for odontalgia management.

The effect of dose expectancies on caffeine withdrawal symptoms during tapered dose reduction

BACKGROUND

Negative expectancies can exacerbate withdrawal symptoms via the nocebo effect. As such, information provided about dose reductions during attempts to taper a drug could contribute to withdrawal symptoms and increase the likelihood of relapse. The current study tested whether blinding participants to dose reductions during a supervised caffeine dose taper reduced these nocebo-induced withdrawal symptoms.

METHODS

Three groups of moderate to heavy coffee drinkers had their dose of caffeine reduced (tapered) from 300 mg per day to 0 mg over the course of five days and reported withdrawal symptoms twice daily. Groups were given differing information about how much caffeine they were receiving. An Open Reduction group was given accurate information about dose reductions. A Blind Reduction group was given no dose information whatsoever. A Deceptive Reduction group was misinformed about dose, with instructions suggesting that the dose remained on 300 mg for three days then dropped to 0 mg.

RESULTS

The Open Reduction group reported more pronounced caffeine withdrawal symptoms than the Deceptive Reduction group on the days with the greatest discrepancy between actual dose and informed dose, indicating a nocebo effect of open versus deceptive reductions. In addition, the rate of increase in reported withdrawal symptoms in the Blind Reduction and Deceptive Reduction groups was less than that of the Open Reduction group.

CONCLUSION

These results suggest that awareness of dose reductions during a dose taper can result in a nocebo withdrawal effect, and that removing this awareness can reduce withdrawal. This has important implications for standard supervised dose-tapering practice, where patients are aware of the timing and magnitude of dose reductions.

Verbal communication about drug dosage balances drug reduction in Parkinson's disease: Behavioral and electrophysiological evidences

INTRODUCTION

Changing drug dosage is common in clinical practice. Recent evidence showed that psychological factors may affect the therapeutic outcome. The aim of this study is to test whether verbal communication about drug dosage changes motor performance and fatigue in Parkinson's Disease (PD) patients.

METHODS

We performed clinical (Unified PD Rating Scale), motor (number of finger flexions and perceived fatigue), and electrophysiological measurements (readiness potential, RP) in PD patients during medication-off and medication-on conditions in three groups. The first group got a full dose of l-dopa and was told it was a full dose. The second group got half dose and was told it was half dose. The third group got half dose, but it was told it was a full standard dose.

RESULTS

We found that overt half dose was less effective than the full dose for clinical improvement, motor performance, and readiness potential. However, if half dose was given along with verbal instructions that it was a full dose, clinical improvement, motor performance and readiness potential were not significantly different from the full dose.

CONCLUSIONS

Our findings indicate that verbal communication about dose reduction is as effective as the 50% dose reduction itself, demonstrating that deceptive information about the dose may have an important impact on the therapeutic outcome. Moreover, the supplementary motor area, source of the RP, seems to be involved in this psychological effect.

The Landscape of Chronic Pain: Broader Perspectives

Chronic pain is a global health concern. This special issue on matters related to chronic pain aims to draw on research and scholarly discourse from an eclectic mix of areas and perspectives. The purpose of this non-systematic topical review is to précis an assortment of contemporary topics related to chronic pain and its management to nurture debate about research, practice and health care policy. The review discusses the phenomenon of pain, the struggle that patients have trying to legitimize their pain to others, the utility of the acute-chronic dichotomy, and the burden of chronic pain on society. The review describes the introduction of chronic primary pain in the World Health Organization's International Classification of Disease, 11th Revision and discusses the importance of biopsychosocial approaches to manage pain, the consequences of overprescribing and shifts in service delivery in primary care settings. The second half of the review explores pain perception as a multisensory perceptual inference discussing how contexts, predictions and expectations contribute to the malleability of somatosensations including pain, and how this knowledge can inform the development of therapies and strategies to alleviate pain. Finally, the review explores chronic pain through an evolutionary lens by comparing modern urban lifestyles with genetic heritage that encodes physiology adapted to live in the Paleolithic era. I speculate that modern urban lifestyles may be painogenic in nature, worsening chronic pain in individuals and burdening society at the population level.

The impact of contextual factors on nursing outcomes and the role of placebo/nocebo effects: a discussion paper

INTRODUCTION

Placebo and nocebo effects represent one of the most fascinating topics in the health care field.

OBJECTIVES

the aims of this discussion paper were (1) to briefly introduce the placebo and nocebo effects, (2) to elucidate the contextual factors able to trigger placebo and nocebo effects in the nursing field, and (3) to debate the impact of contextual factors on nursing education, practice, organisation, and research.

METHODS

a narrative review was conducted based on the available evidence.

RESULTS

Placebo responses (from Latin "I shall please") are a beneficial outcome(s) triggered by a positive context. The opposite are the nocebo effects (from Latin "I shall harm"), which indicates an undesirable outcome(s) caused by a negative context. Both are complex and distinct psychoneurobiological phenomena in which behavioural and neurophysiological changes arise subsequent to an interaction between the patient and the health care context.

CONCLUSION

Placebo and nocebo concepts have been recently introduced in the nursing discipline, generating a wide debate on ethical issues; however, the impact on nursing education, clinical practice, nursing administration, and research regarding contextual factors triggering nocebo and placebo effects has not been debated to date.

A novel neurocognitive approach for placebo analgesia in neurocognitive disorders

Neural correlates of placebo analgesia (PA) in patients with neurocognitive disorders have not yet been elucidated. The present study aimed to evaluate how and to what extent executive (dys)functions of the medial prefrontal cortex (MPFC) may be related to PA. To this end, twenty-three subjects complaining of different cognitive deficits (from mild cognitive impairment likely due to Alzheimer's disease to mild AD) were recruited. PA was investigated by a well-known experimental venipuncture pain paradigm (open versus hidden [O-H] application of lidocaine). Patients also underwent a comprehensive neuropsychological evaluation and a functional magnetic resonance imaging (fMRI) GO/No-GO task for eliciting selective activation of the MPFC. Selected neuropsychological variables were correlated to the OH-PA paradigm. The association between the fMRI response on the "No-GO" versus "GO" contrast and PA was investigated over the whole-brain by regression analysis. We showed the existence of a relationship between a lower PA and MPFC dysfunctions through the neuropsychological and fMRI assessment. A separate voxel-based morphometry (VBM) analysis controlled for possible influence of grey matter (GM) volume reduction on both fMRI results and PA. fMRI results were not directly affected by, and therefore independent of, disease-specific GM atrophy, which was indeed located more anteriorly within the rostral anterior cingulate and inversely correlated with PA. Our findings shed new light on the underestimated contribution of executive (dys)functions mediated by the MPFC (response-inhibition, self-monitoring and set-shifting abilities) in PA pathogenesis, with a special purely (i.e. independently from brain structural alterations) functional role played by the MCC. Results are discussed in terms of possible clinical relevance in the management of patients with neurocognitive disorders.

Harnessing the power of placebos in movement disorders: Insights from Parkinson's disease in clinical research and practice

The placebo effect alongside the detrimental nocebo and lessebo effects associated with the use of placebos are well-recognized phenomena. Research conducted in the last two decades has demonstrated that the placebo effect is a measurable health benefit with well-known neurobiological correlates. In this review, we describe the current knowledge about how to best make use of the placebo effect to improve clinical research and optimize clinical care. We will cover four key topics: (1) setting the stage: historical perspectives on the use of placebos; (2) optimizing the use of placebos in clinical trials; (3) use of placebos in clinical practice; and (4) how can we minimize the ethical risks of using placebos? The adoption of the placebo-controlled trial as a standard in the therapeutic development reduced the placebo effect to background noise in a therapeutic signal. Strategies to minimize the placebo effect in clinical trials have been used to obtain positive efficacy results. In more recent years, new study paradigms encouraged a change in the views on placebos and the placebo effect. Alternative study designs and the development of biomarkers for a placebo response permit a better understanding of the contribution of the placebo effect to the results of interventional studies, without minimizing it. In clinical practice, optimizing the placebo effect (and reducing nocebo effects) has the potential to improve care for our patients, but raises ethical challenges. An enhanced patient-physician relationship would be central to any evidence-based intervention used in clinical care to heighten the placebo effect. © 2018 International Parkinson and Movement Disorder Society.

Placebo by proxy expectations toward acupuncture change over time: a survey comparing parental expectations to acupuncture pre- and postoperatively

Background

Patients entering a treatment have expectancy to outcome based on their previous experience, the information received, and the credibility of the treatment. Once the treatment has started, patients may detect and interpret contextual cues and somatic state. Influenced and conditioned by positive or negative interpretations, their reappraisal may improve or worsen the treatment outcome. The aims were to investigate whether parental pre-treatment expectancies towards acupuncture differ compared to post-treatment expectancies, and assess predictors for possible change of parental expectancy. Further, we wanted to explore whether the change correlates with the treatment outcome, i.e. postoperative vomiting in children.

Methods

Two hundred and eighty-two parents completed per- and 24 h postoperatively a survey on their expectancy to acupuncture treatment for alleviation of postoperative vomiting in children. The survey was embedded in a randomised controlled trial.

Results

Parental expectancy to acupuncture treatment changed over time. The changes were predicted by several variables such as children’s gender, parents’ age and education, previous experiences, and assignment to treatment group. The strongest predictor was parental anxiety to their child undergoing surgery. Further, the change of parental expectancy was correlated with postoperative vomiting.

Conclusions

Anxious parents are prone to change their expectancy in a positive direction during the treatment period, which in turn may improve treatment outcome. Acupuncture therapists in clinical practice should pay a special attention to the potential that lies here, and acknowledge parental anxiety as a possible facilitator, and not a barrier, to elicit placebo by proxy effects. Further research to expand the findings of the present study into other treatments is in order. Future research should also provide more knowledge about how parental expectancy changes over time, and how different factors predict and produce change of parental expectancy.

Trial registration

ClinicalTrials.gov NCT01729052. Registered November 20, 2012.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2248-z) contains supplementary material, which is available to authorized users.

Can knowledge of Placebo and Nocebo Mechanisms Help Improve Randomized Clinical Trials?

Over the last decade, there has been a substantial increase in negative results from randomized controlled trials (RCTs), which may be due to an increasing placebo response among other factors. Currently, identification and exclusion of placebo responders from trials are attempted to overcome this problem, but so far the success of these approaches has been limited. At the same time, the placebo-mechanism literature has highlighted how contextual factors, such as patients' expectations, interfere with the effect of drug administration, leading to a certain degree of uncertainty in RCTs. In this chapter, we review the current challenges of RCTs including the uncertainties of the active arm, the placebo arm, the additivity assumption, and the double-blind procedure. We use the placebo-mechanism literature to debate the strengths and weaknesses of attempts to identify and exclude placebo responders from trials. Finally, we illustrate how insights from the placebo-mechanism literature may point to new ways of improving RCTs.

No effect of a pulsed magnetic field on induced ischemic muscle pain. A double-blind, randomized, placebo-controlled trial

Empirical evidence supporting the effectiveness of pulsed (electro)magnetic field (PEMF) therapy on chronic and acute pain is equivocal. In the current randomized, double-blind, placebo-controlled experiment, impact of a commercially available whole-body PEMF mat on acute ischemic muscle pain induced in the forearm was studied with the participation of 70 healthy volunteers. The device emitted a pulsed magnetic field with a repetition frequency of 2.05Hz and a maximum flux density of 25.3μT (rms). The highest dB/dt was 48mT/s. No differences between the groups receiving actual and sham PEMF were found in terms of pain threshold, pain tolerance, heart rate, and perceived decrease of pain. However, participants' expectation concerning the effectiveness of the intervention improved pain tolerance and affected perceived change of pain. In conclusion, the used PEMF device had no specific effect on acute ischemic muscle pain, while the contribution of the placebo effect was considerable.

Clinical relevance of contextual factors as triggers of placebo and nocebo effects in musculoskeletal pain

Placebo and nocebo effects are embodied psycho-neurobiological responses capable of modulating pain and producing changes at different neurobiological, body at perceptual and cognitive levels. These modifications are triggered by different contextual factors (CFs) presented in the therapeutic encounter between patient and healthcare providers, such as healing rituals and signs. The CFs directly impact on the quality of the therapeutic outcome: a positive context, that is a context characterized by the presence of positive CFs, can reduce pain by producing placebo effects, while a negative context, characterized by the presence of negative CFs, can aggravate pain by creating nocebo effects. Despite the increasing interest about this topic; the detailed study of CFs as triggers of placebo and nocebo effects is still lacked in the management of musculoskeletal pain.

Increasing evidence suggest a relevant role of CFs in musculoskeletal pain management. CFs are a complex sets of internal, external or relational elements encompassing: patient’s expectation, history, baseline characteristics; clinician’s behavior, belief, verbal suggestions and therapeutic touch; positive therapeutic encounter, patient-centered approach and social learning; overt therapy, posology of intervention, modality of treatment administration; marketing features of treatment and health care setting. Different explanatory models such as classical conditioning and expectancy can explain how CFs trigger placebo and nocebo effects. CFs act through specific neural networks and neurotransmitters that were described as mediators of placebo and nocebo effects.

Available findings suggest a relevant clinical role and impact of CFs. They should be integrated in the clinical reasoning to increase the number of treatment solutions, boosts their efficacy and improve the quality of the decision-making. From a clinical perspective, the mindful manipulation of CFs represents a useful opportunity to enrich a well-established therapy in therapeutic setting within the ethical border. From a translational perspective, there is a strong need of research studies on CFs close to routine and real-world clinical practice in order to underline the uncertainty of therapy action and help clinicians to implement knowledge in daily practice.

Methods for assessing and controlling placebo effects

The placebo serves as an indispensable control in many randomized trials. When analyzing the benefit of a new treatment, researchers are often confronted with large placebo effects that diminish the treatment effect. Various alternative methods have been proposed for analyzing placebo and treatment effects in studies where large placebo effects are expected or have already occurred. This paper presents an overview of methodological work that has been proposed for assessing and/or controlling for placebo effects in randomized trials. Throughout this paper, two main approaches are discussed. The first approach considers designs that represent alternatives to the classical placebo-controlled randomized trial design. Separately, the second approach considers adopting new methods for the statistical analysis of placebo and treatment effects to be implemented after the data have been collected using a classical randomized trial design.

An enactive account of placebo effects

Placebos are commonly defined as ineffective treatments. They are treatments that lack a known mechanism linking their properties to the properties of the condition on which treatment aims to intervene. Given this, the fact that placebos can have substantial therapeutic effects looks puzzling. The puzzle, we argue, arises from the relationship placebos present between culturally meaningful entities (such as treatments or therapies), our intentional relationship to the environment (such as implicit or explicit beliefs about a treatment's healing powers) and bodily effects (placebo responses). How can a mere attitude toward a treatment result in appropriate bodily changes? We argue that an 'enactive' conception of cognition accommodates and renders intelligible the phenomenon of placebo effects. Enactivism depicts an organism's adaptive bodily processes, its intentional directedness, and the meaningful properties of its environment as co-emergent aspects of a single dynamic system. In doing so it provides an account of the interrelations between mind, body and world that demystifies placebo effects.

Nature of the placebo and nocebo effect in relation to functional neurologic disorders

Placebos have long been considered a nuisance in clinical research, for they have always been used as comparators for the validation of new treatments. By contrast, today they represent an active field of research, and, due to the involvement of many mechanisms, the study of the placebo effect can actually be viewed as a melting pot of concepts and ideas for neuroscience. There is not a single placebo effect, but many, with different mechanisms across different medical conditions and therapeutic interventions. Expectation, anxiety, and reward are all involved, as well as a variety of learning phenomena and genetic variants. The most productive models to better understand the neurobiology of the placebo effect are pain and Parkinson's disease. In these medical conditions, several neurotransmitters have been identified, such as endogenous opioids, cholecystokinin, dopamine, as well as lipidic mediators, for example, endocannabinoids and prostaglandins. Since the placebo effect is basically a psychosocial context effect, these data indicate that different social stimuli, such as words and therapeutic rituals, may change the chemistry of the patient's brain, and these effects are similar to those induced by drugs.

Drug versus placebo randomized controlled trials in neonates: A review of ClinicalTrials.gov registry

BACKGROUND

Despite specific initiatives and identified needs, most neonatal drugs are still used off-label, with variable dosage administrations and schedules. In high risk preterm and term neonates, drug evaluation is challenging and randomized controlled trials (RCT) are difficult to conduct and even more is the use of a placebo, required in the absence of a reference validated drug to be used as comparator.

METHODS

We analyzed the complete ClinicalTrials.gov registry 1) to describe neonatal RCT involving a placebo, 2) to report on the medical context and ethical aspects of placebo use.

RESULTS

Placebo versus drug RCT (n = 146), either prevention trials (n = 57, 39%) or therapeutic interventions (n = 89, 61%), represent more than a third of neonatal trials registered in the National Institute of Health clinical trial database (USA) since 1999. They mainly concerned preterm infants, evaluating complications of prematurity. Most trials were conducted in the USA, were single centered, and funded by non-profit organizations. For the three top drug trials evaluating steroids (n = 13, 9.6%), erythropoietin (EPO, n = 10, 6.8%) and nitric oxide (NO, n = 9, 6.2%), the objectives of the trial and follow-up were analyzed in more details.

CONCLUSION

Although a matter of debate, the use of placebo should be promoted in neonates to evaluate a potential new treatment, in the absence of reference drug. Analysis of the trials evaluating steroids showed that long-term follow-up of exposed patients, although required by international guidelines, is frequently missing and should be planned to collect additional information and optimize drug evaluation in these high-risk patients.

Are placebo and drug-specific effects additive? Questioning basic assumptions of double-blinded randomized clinical trials and presenting novel study designs

Double-blinded randomized clinical trials (RCTs) assume that pharmacological interventions have drug-specific and unspecific components. Traditional RCTs postulate an additivity of these two components. In this review, we provide evidence from both clinical trials and experimental studies that questions this 'additive model'. Given that the evaluation of drug treatments in RCTs is based on the assumption of additivity, its violation has far-reaching consequences. Therefore, we discuss an interactive model that, in contrast to the additive model, considers interactions between placebo and drug-specific effects. Moreover, we discuss implications for future clinical trials and present novel study designs enabling researchers to consider the complex interplay of drug-specific and unspecific effects.

Placebo Response is Driven by UCS Revaluation: Evidence, Neurophysiological Consequences and a Quantitative Model

Despite growing scientific interest in the placebo effect and increasing understanding of neurobiological mechanisms, theoretical modeling of the placebo response remains poorly developed. The most extensively accepted theories are expectation and conditioning, involving both conscious and unconscious information processing. However, it is not completely understood how these mechanisms can shape the placebo response. We focus here on neural processes which can account for key properties of the response to substance intake. It is shown that placebo response can be conceptualized as a reaction of a distributed neural system within the central nervous system. Such a reaction represents an integrated component of the response to open substance administration (or to substance intake) and is updated through “unconditioned stimulus (UCS) revaluation learning”. The analysis leads to a theorem, which proves the existence of two distinct quantities coded within the brain, these are the expected or prediction outcome and the reactive response. We show that the reactive response is updated automatically by implicit revaluation learning, while the expected outcome can also be modulated through conscious information processing. Conceptualizing the response to substance intake in terms of UCS revaluation learning leads to the theoretical formulation of a potential neuropharmacological treatment for increasing unlimitedly the effectiveness of a given drug.

A System Computational Model of Implicit Emotional Learning

Nowadays, the experimental study of emotional learning is commonly based on classical conditioning paradigms and models, which have been thoroughly investigated in the last century. Unluckily, models based on classical conditioning are unable to explain or predict important psychophysiological phenomena, such as the failure of the extinction of emotional responses in certain circumstances (for instance, those observed in evaluative conditioning, in post-traumatic stress disorders and in panic attacks). In this manuscript, starting from the experimental results available from the literature, a computational model of implicit emotional learning based both on prediction errors computation and on statistical inference is developed. The model quantitatively predicts (a) the occurrence of evaluative conditioning, (b) the dynamics and the resistance-to-extinction of the traumatic emotional responses, (c) the mathematical relation between classical conditioning and unconditioned stimulus revaluation. Moreover, we discuss how the derived computational model can lead to the development of new animal models for resistant-to-extinction emotional reactions and novel methodologies of emotions modulation.

Different contexts, different pains, different experiences

Pain is an ambiguous perception: the same pain stimulation can be perceived differently in different contexts, producing different experiences, ranging from mild to unbearable pain. It can be even experienced as a rewarding sensation within the appropriate context. Overall, placebo and nocebo effects appear to be very good models to understand how the psychosocial context modulates the experience of pain. In this review, we examine the effects of different contexts on pain, with a specific focus on the neurobiological mechanisms. Positive and rewarding contexts inform the patients that an effective treatment is being delivered and are capable of producing pain relief through the activation of specific systems such as opioids, cannabinoids and dopamine. Conversely, a negative context can produce pain exacerbation and clinical worsening through the modulation of different systems, such as the activation of cholecystokinin and the deactivation of opioids and dopamine. In addition, when a therapy is delivered unbeknownst to the patient, its effects are reduced. A better understanding of the neurobiological underpinnings of the context-pain interaction is a challenge both for future pain research and for good clinical practice.

Evaluating clinical trial design: systematic review of randomized vehicle-controlled trials for determining efficacy of benzoyl peroxide topical therapy for acne

Determined efficacies of benzoyl peroxide may be affected by study design, implementation, and vehicle effects. We sought to elucidate areas that may allow improvement in determining accurate treatment efficacies by determining rates of active treatment and vehicle responders in randomized controlled trials assessing the efficacy of topical benzoyl peroxide to treat acne. We conducted a systematic review of randomized vehicle-controlled trials evaluating the efficacy of topical benzoyl peroxide for the treatment of acne. We compared response rates of vehicle treatment arms versus those in benzoyl peroxide arms. Twelve trials met inclusion criteria with 2818 patients receiving benzoyl peroxide monotherapy treatment and 2004 receiving vehicle treatment. The average percent reduction in total number of acne lesions was 44.3 (SD = 9.2) and 27.8 (SD = 21.0) for the active and vehicle treatment groups, respectively. The average reduction in non-inflammatory lesions was 41.5 % (SD = 9.4) in the active treatment group and 27.0 % (SD = 20.9) in the vehicle group. The average percent decrease in inflammatory lesions was 52.1 (SD = 10.4) in the benzoyl peroxide group and 34.7 (SD = 22.7) in the vehicle group. The average percentage of participants achieving success per designated study outcomes was 28.6 (SD = 17.3) and 15.2 (SD = 9.5) in the active treatment and vehicle groups, respectively. Patient responses in randomized controlled trials evaluating topical acne therapies may be affected by clinical trial design, implementation, the biologic effects of vehicles, and natural disease progression. "No treatment" groups may facilitate determination of accurate treatment efficacies.

Placebo and nocebo effects: a complex interplay between psychological factors and neurochemical networks

Placebo and nocebo effects have recently emerged as an interesting model to understand some of the intricate underpinnings of the mind-body interaction. A variety of psychological mechanisms, such as expectation, conditioning, anxiety modulation, and reward, have been identified, and a number of neurochemical networks have been characterized across different conditions, such as pain and motor disorders. What has emerged from the recent insights into the neurobiology of placebo and nocebo effects is that the psychosocial context around the patient and the therapy, which represents the ritual of the therapeutic act, may change the biochemistry and the neuronal circuitry of the patient's brain. Furthermore, the mechanisms activated by placebos and nocebos have been found to be the same as those activated by drugs, which suggests a cognitive/affective interference with drug action. Overall, these findings highlight the important role of therapeutic rituals in the overall therapeutic outcome, including hypnosis, which may have profound implications both in routine medical practice and in the clinical trials setting.

Placebo effects: from the neurobiological paradigm to translational implications

Today we are witnessing a new science of placebo, a complex discipline that encompasses several experimental approaches and translational implications. Modern neurobiological tools have been used to answer important questions in placebo research, such as the top-down modulation of sensory and motor systems as well as the influence of cognition, emotions, and learning on symptoms, diseases, and responses to treatments. What we have learned is that there is not one single placebo effect, but many. This review highlights the translational implications of this new knowledge, ranging from clinical trial design to medical practice to social and ethical issues.

Pain and the context

Pain is a sensory and emotional experience that is substantially modulated by psychological, social and contextual factors. Research now indicates that the influence of these factors is even more powerful than expected and involves the therapeutic response to analgesic drugs as well as the pain experience itself, which in some circumstances can even be a form of reward. Different experimental approaches and models, both in the laboratory and in the clinical setting, have been used to better characterize and understand the complex neurobiology of pain modulation. These approaches include placebo analgesia, nocebo hyperalgesia, hidden administration of analgesics, and the manipulation of the pain-reward relationship. Overall, these studies show that different neurochemical systems are activated in different positive and negative contexts. Moreover, pain can activate reward mechanisms when experienced within contexts that have special positive meaning. Because routine medical practice usually takes place in contexts that use different rituals, these neurobiological insights might have profound clinical implications.

Traditional and innovative experimental and clinical trial designs and their advantages and pitfalls

Many study designs and design variants have been developed in the past to either overcome or enhance drug-placebo differences in clinical trials or to identify and characterize placebo responders in experimental studies. They share many commonalities as well as differences that are discussed here: the role of deception and ethical restrictions, habituation effects and the control of the natural course of disease, assay sensitivity testing and effective blinding, acceptability and motivation of patients and volunteers, and the development of individualized medicine. These are fostered by two opposite strategies: utilizing the beneficial aspects of the placebo response-and avoiding its negative counterpart, the nocebo effect-in medical routine for the benefit of patients, and minimizing-by controlling-the negative aspects of the placebo effect during drug development.