The effect of treatment expectation on drug efficacy: imaging the analgesic benefit of the opioid remifentanil

[Placebo effects in pain therapy]

In the past few decades, research on pain and placebo analgesia has gained importance both scientifically and clinically. In this article, the current findings and focus of research as well as the significance of placebo research for assessing the effectiveness of pain medication are illustrated. The underlying mechanisms of placebo analgesia not only have implications for theoretical models but also offer clinically relevant guidelines for everyday interventions in pain treatment. However, many placebo phenomena are not fully understood and have to be investigated further in order to exploit the full potential of placebo effects. Interindividual differences and their inclusion in treatment will play a major role in this aspect.

The science of belief: A progress report

The empirical study of belief is emerging at a rapid clip, uniting work from all corners of cognitive science. Reliance on belief in understanding and predicting behavior is widespread. Examples can be found, inter alia, in the placebo, attribution theory, theory of mind, and comparative psychological literatures. Research on belief also provides evidence for robust generalizations, including about how we fix, store, and change our beliefs. Evidence supports the existence of a Spinozan system of belief fixation: one that is automatic and independent of belief rejection. Independent research supports the existence of a system of fragmented belief storage: one that relies on large numbers of causally isolated, context-sensitive stores of belief in memory. Finally, empirical and observational data support at least two systems of belief change. One system adheres, mostly, to epistemological norms of updating; the other, the psychological immune system, functions to guard our most centrally held beliefs from potential inconsistency with newly formed beliefs. Refining our understanding of these systems can shed light on pressing real-world issues, such as how fake news, propaganda, and brainwashing exploit our psychology of belief, and how best to construct our modern informational world. This article is categorized under: Psychology > Reasoning and Decision Making Philosophy > Knowledge and Belief Philosophy > Foundations of Cognitive Science.

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.

Statins in a Distorted Mirror of Media

PURPOSE OF REVIEW

Statins have proven efficacy with a favorable safety profile yet, despite being widely affordable, remain profoundly underutilized. Statins have acquired a bad reputation, which is likely contributing to high rates of nonadherence and discontinuation. The degree to which negative media perceptions contribute to underutilization is unclear.

RECENT FINDINGS

The media has a key role in informing discussion on the public agenda but also on how issues are framed. In this context, the majority of studies evaluating news coverage suggest that the content on statins is predominantly negative and focused on potential harm. Studies utilizing quasi-experimental and interrupted time series design have shown periods of negative news stories on statins in multiple countries are associated with (a) less statin commencement in eligible patients, (b) high rates of discontinuation, and (c) poor long-term adherence. This review highlights the deleterious impact of negative media coverage on statin utilization through misattribution of muscle complaints and the nocebo effect. Academia must work with the media to harmonize the public health messaging; however, individual physicians have a critical role in mitigating a harmful narrative of misinformation and actively discredit malinformation.

Context matters: the psychoneurobiological determinants of placebo, nocebo and context-related effects in physiotherapy

Background

Placebo and nocebo effects embody psychoneurobiological phenomena where behavioural, neurophysiological, perceptive and cognitive changes occur during the therapeutic encounter in the healthcare context. Placebo effects are produced by a positive healthcare context; while nocebo effects are consequences of negative healthcare context. Historically, placebo, nocebo and context-related effects were considered as confounding elements for clinicians and researchers. In the last two decades this attitude started to change, and the understanding of the value of these effects has increased. Despite the growing interest, the knowledge and the awareness of using the healthcare context to trigger placebo and nocebo effects is currently limited and heterogeneous among physiotherapists, reducing their translational value in the physiotherapy field.

Objectives

To introduce the placebo, nocebo and context-related effects by: (1) presenting their psychological models; (2) describing their neurophysiological mechanisms; (3) underlining their impact for the physiotherapy profession; and (4) tracing lines for future researches.

Conclusion

Several psychological mechanisms are involved in placebo, nocebo and context-related effects; including expectation, learning processes (classical conditioning and observational learning), reinforced expectations, mindset and personality traits. The neurophysiological mechanisms mainly include the endogenous opioid, the endocannabinoid and the dopaminergic systems. Neuroimaging studies have identified different brain regions involved such as the dorsolateral prefrontal cortex, the rostral anterior cingulate cortex, the periaqueductal gray and the dorsal horn of spine. From a clinical perspective, the manipulation of the healthcare context with the best evidence-based therapy represents an opportunity to trigger placebo effects and to avoid nocebo effects respecting the ethical code of conduct. From a managerial perspective, stakeholders, organizations and governments should encourage the assessment of the healthcare context aimed to improve the quality of physiotherapy services. From an educational perspective, placebo and nocebo effects are professional topics that should be integrated in the university program of health and medical professions. From a research perspective, the control of placebo, nocebo and context-related effects offers to the scientific community the chance to better measure the impact of physiotherapy on different outcomes and in different conditions through primary studies.

Optimizing patient expectations to improve therapeutic response to medical treatment: A randomized controlled trial of iron infusion therapy

OBJECTIVES

Patient expectations have the ability to influence health outcomes and have been shown to play an important role as part of the placebo effect to influence the response to medical treatments. Increasing positive expectations have been proposed as an intervention to improve treatment response, although evidence for this to date is limited. We investigated whether a brief 10-min intervention directly targeting patient expectations prior to an iron infusion could enhance expectations and improve treatment response, in terms of patients' reported fatigue.

DESIGN

Randomized controlled trial.

METHODS

Forty-three patients diagnosed with iron deficiency anaemia were randomized to a brief expectation intervention or active control group prior to an intravenous iron infusion. Chalder Fatigue Scale scores were assessed prior to randomization and at one and four weeks.

RESULTS

The expectation intervention significantly improved patients' expectations about the effectiveness of the intravenous iron infusion, t(21) = -3.95, p = .001. While there were no significant differences between groups in fatigue at the one-week follow-up, fatigue was significantly lower in the intervention group at the four-week follow-up compared to the control group, F(1, 25) = 6.25, p = .019. This was largely influenced by a significant reduction in physical, as opposed to mental fatigue scores.

CONCLUSIONS

Boosting patients' positive expectations may be an effective way of enhancing patient response to treatment. In particular, targeting patient expectations with a brief intervention prior to medical treatments may result in a greater and longer therapeutic effect.

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.

Medial Orbitofrontal De-Activation During Tonic Cold Pain Stimulation: A fMRI Study Examining the Opponent-Process Theory

BACKGROUND

While the concomitant administration of painful and rewarding stimuli tends to reduce the perception of one another, recent evidence shows that pleasant pain relief is experience after the interruption of noxious stimuli. On neurobiological grounds, these opponent processes should translate into decreased activity in brain reward regions during nociceptive stimulation and increased activity in these regions after its interruption. While growing evidence supports the latter assumption, evidence is lacking in humans in support of the former.

METHODS

Twenty-six healthy individuals underwent a functional magnetic resonance imaging (fMRI) session during which they were administered a cold pain stimulation, using a novel paradigm which consisted in a cold gel applied on the right foot of participants.

RESULTS

After the interruption of noxious stimulation, participants experienced significant levels of pleasant pain relief. During cold pain stimulation, brain activations were observed in key regions of the pain matrix (eg, thalamus, primary somatosensory cortex and insula). Conversely, the medial orbitofrontal cortex was found to be de-activated. Medial orbitofrontal de-activations were negatively correlated with subclinical pain symptoms.

DISCUSSION

Our results show that a key brain reward region (eg, medial orbitofrontal cortex) is de-activated during cold pain stimulation, a result which is consistent with one of the central assumptions of the opponent-process theory. On methodological grounds, our results show that the cold gel applied to the foot can be used to trigger activations in the pain matrix, and that the interruption of the cold pressor test elicits significant levels of pleasant pain relief. fMRI studies on pain-reward interactions in chronic pain patients are warranted.

Mixed methods analysis of Health-Related Quality of Life in ambulant individuals affected with RYR1-related myopathies pre-post-N-acetylcysteine therapy

PURPOSE

To characterize Health-Related Quality of Life (HRQoL) in ambulant individuals with RYR1-RM and to determine if a qualitative PRO tool (subjective self-assessment) complements PROMIS and Neuro-QoL scales to detect changes in HRQoL in ambulant individuals with RYR1-RM post N-acetylcysteine (NAC) treatment.

METHODS

The study used a mixed methods research (MMR) design applying methodological triangulation. Qualitative data were collected via semi-structured interviews using open-ended questions. Quantitative data were gathered through PROMIS and Neuro-QoL instruments. Additionally, qualitative data were transformed into quantitative data for subjective self-assessment and frequency analyses.

RESULTS

Qualitative results identified five domains and 33 subdomains as areas of interest. The most valuable were the importance of social impacts, the development of several coping strategies, both physical and psychological, and the identification of fatigue and weakness as key symptoms. Data transformation then categorized more than 3100 citations on frequency analyses, globally and by domain, visit, and participant. Regarding quantitative results, there was no clear evidence that any of the three PRO tools captured positive changes as a result of NAC treatment.

CONCLUSION

Qualitative results showed a comprehensive characterization of HRQoL in this population based on a symptom/patient-centered approach. These findings will inform future studies. Furthermore, given the similar findings across our multiple methods and endpoints, the introduction of MMR may be a valuable, complementary approach to clinical trials. MMR may be especially useful to incorporate in order to address and follow the FDA's guidance and prioritization on the inclusion of affected individuals' perspectives in clinical trials.

Pain Catastrophizing Mediates the Association Between Mindfulness and Psychological Distress in Chronic Pain Syndrome

AIM

Trait mindfulness has been found to be inversely associated with emotional distress such as depression and anxiety among patients suffering from pain. The current study investigated the putative mechanisms underlying these associations by examining whether pain catastrophizing mediates the association between mindfulness and psychological distress and whether this model differs in patients suffering from chronic pain compared to patients experiencing nonchronic pain in a medical rehabilitation setting.

METHODS

Forty-eight patients in their subacute stage of recovery participated in the study. Seventeen participants had a diagnosis of chronic pain. Trait mindfulness was assessed using the Mindful Attention Awareness Scale, pain catastrophizing was assessed using the Pain Catastrophizing Scale, depression symptoms were assessed using the Patient Health Questionnaire, and anxiety was assessed using the Generalized Anxiety Disorder scale. Two mediation models were used, with pain catastrophizing mediating the association between mindfulness and depression and anxiety.

RESULTS

Catastrophizing significantly mediated the association between trait mindfulness and depression (P < 0.05, confidence interval [CI] = -0.35, -0.05). Catastrophizing also mediated the relationship between trait mindfulness and anxiety (P < 0.05, CI = -0.34, -0.04). Two moderated mediation models were tested, in which pain catastrophizing fully mediated the relationship between trait mindfulness and depression and anxiety, but only in patients with chronic pain.

CONCLUSIONS

The negative association between trait mindfulness and psychological distress may thus be partly attributed to pain catastrophizing: individuals high in trait mindfulness engage in less catastrophic thinking and therefore experience less distress. Importantly, this was only observed in the patients with chronic pain. These results further underscore the need to cope with pain catastrophizing and encourage mindfulness among patients with chronic pain.

Prescribing Placebos: An Experimental Examination of the Role of Dose, Expectancies, and Adherence in Open-Label Placebo Effects

Background

Recent evidence indicates that placebo effects can occur even when patients know that they are taking a placebo, termed the open-label placebo effect.

Aim

To assess whether placebo dose (one pill per day vs. four pills per day), treatment expectancies, and adherence contribute to open-label placebo effects.

Method

Healthy undergraduate participants were randomly assigned to take one or four open-label placebo pills per day or to a no-treatment control group. Placebo-treated participants took a 5-day course of an open-label placebo described as enhancing physical (symptoms and sleep) and psychological (positive and negative emotional experience) well-being. Expectancies about placebo effectiveness and well-being were assessed at baseline, and well-being and adherence were assessed after the 5-day course of treatment.

Results

Medium-to-large open-label placebo effects were evidenced in all well-being outcomes including sleep quality. Dose did not influence these effects. Both treatment expectancies and adherence were significant independent predictors of enhanced well-being in the two psychological well-being outcomes and the experience of physical symptoms, but sleep quality improved independently.

Conclusions

This is the first study to demonstrate the effect of open-label placebos in improving well-being and sleep quality and to show that open-label placebo reposes do not appear to be dose-dependent, but for most well-being outcomes are independently predicted by both positive expectancies and treatment adherence.

Cognitive and Emotional Aspects of Cupping Therapy

Cupping therapy has recently gained public attention and is widely used in many regions. Some patients are resistant to being treated with cupping therapy, as visually unpleasant marks on the skin may elicit negative reactions. This study aimed to identify the cognitive and emotional components of cupping therapy. Twenty-five healthy volunteers were presented with emotionally evocative visual stimuli representing fear, disgust, happiness, neutral emotion, and cupping, along with control images. Participants evaluated the valence and arousal level of each stimulus. Before the experiment, they completed the Fear of Pain Questionnaire-III. In two-dimensional affective space, emotional arousal increases as hedonic valence ratings become increasingly pleasant or unpleasant. Cupping therapy images were more unpleasant and more arousing than the control images. Cluster analysis showed that the response to cupping therapy images had emotional characteristics similar to those for fear images. Individuals with a greater fear of pain rated cupping therapy images as more unpleasant and more arousing. Psychophysical analysis showed that individuals experienced unpleasant and aroused emotional states in response to the cupping therapy images. Our findings suggest that cupping therapy might be associated with unpleasant-defensive motivation and motivational activation. Determining the emotional components of cupping therapy would help clinicians and researchers to understand the intrinsic effects of cupping therapy.

Pain reduction by inducing sensory-motor adaptation in Complex Regional Pain Syndrome (CRPS PRISMA): protocol for a double-blind randomized controlled trial

BACKGROUND

Complex Regional Pain Syndrome (CRPS) presents as chronic, continuous pain and sensory, autonomic, and motor abnormalities affecting one or more extremities. People with CRPS can also show changes in their perception of and attention to the affected body part and sensory information in the affected side of space. Prism Adaptation (PA) is a behavioural intervention targeted at reducing attention deficits in post-stroke hemispatial neglect. PA also appears to reduce pain and other CRPS symptoms; however, these therapeutic effects have been demonstrated only in small unblinded studies. This paper describes the protocol for an ongoing double-blind, randomized, sham-controlled clinical trial that will evaluate the efficacy of PA treatment for CRPS. The secondary aims of the study are to examine the relationships between neuropsychological changes (such as spatial attention, space and body representation, and motor spatial performance) and clinical manifestations of CRPS, as well as symptom improvement.

METHODS

Forty-two participants with upper-limb CRPS type I will undergo 2 weeks of twice-daily PA treatment or sham treatment. The primary outcome measures are current pain intensity and CRPS severity score, measured immediately before and after the treatment period. Secondary outcome measures include the results of self-report questionnaires about pain, movement, symptoms interference, and body representation; clinical assessments of sensory, motor, and autonomic functions; and computer-based psychophysical tests of neuropsychological functions. Data are collected in four research visits: 4 weeks and 1 day before treatment, and 1 day and 4 weeks after the end of treatment. Additional follow-up through postal questionnaires is conducted 3 and 6 months post-treatment.

DISCUSSION

It is hypothesised that participants undergoing PA treatment, compared to those receiving sham treatment, will show greater reduction in pain and CRPS severity score, and improvements on other clinical and neuropsychological measures. Also, more pronounced neuropsychological symptoms are predicted to correlate with more severe clinical CRPS symptoms. This study will provide the first randomized double-blind evaluation of the therapeutic effects of PA that could be implemented as a rehabilitation method for CRPS, and will contribute to the understanding of how neuropsychological changes in body representation and attention pertain to the manifestation and treatment of CRPS.

TRIAL REGISTRATION

(27/03/2017): ISRCTN46828292 (ISRCTN - ISRCTN46828292: Treatment of complex regional pain syndrome (CRPS) with sensory-motor adaptation).

Verbal suggestions of nicotine content modulate ventral tegmental neural activity during the presentation of a nicotine-free odor in cigarette smokers

Expectancies of nicotine content have been shown to impact smokers' subjective responses and smoking behaviors. However, little is known about the neural substrates modulated by verbally induced expectancies in smokers. In this study we used functional magnetic resonance imaging (fMRI) to investigate how verbally induced expectations, regarding the presence or absence of nicotine, modulated smokers' neural response to a nicotine-free odor. While laying in the scanner, all participants (N = 24) were given a nicotine-free odor, but whereas one group was correctly informed about the absence of nicotine (control group n = 12), the other group was led to believe that the presented odor contained nicotine (expectancy group n = 12). Smokers in the expectancy group had significantly increased blood-oxygen-level-dependent (BOLD) responses during the presentation of the nicotine-free odor in the left ventral tegmental area (VTA), and in the right insula, as compared to smokers in the control group (Regions of interest analysis with pFWE-corrected p ≤ 0.05). At a more liberal uncorrected statistical level (p-unc ≤ 0.001), increased bilateral reactivity in the dorsolateral prefrontal cortex (dlPFC) was also observed in the expectancy group as compared with the control group. Our findings suggest that nicotine-expectancies induced through verbal instructions can modulate nicotine relevant brain regions, without nicotine administration, and provide further neural support for the key role that cognitive expectancies play in the cause and treatment of nicotine dependence.

Issues Impacting Adverse Event Frequency and Severity: Differences Between Randomized Phase 2 and Phase 3 Clinical Trials for Lasmiditan

Objective

We explore factors that may have contributed to differences in treatment‐emergent adverse events in the phase 2 and phase 3 lasmiditan clinical trials.

Background

Phase 2 and phase 3 trials showed that the centrally penetrant 5‐HT_1F agonist, lasmiditan, was effective; higher frequency and severity of adverse events (AEs) were seen in phase 2.

Methods

This work represents a hybrid of a review of primary documents and study reports with additional post hoc analyses. Protocols, informed consents, data collection forms, and methodologies were reviewed. This information was supplemented by results from the clinical study reports and post hoc analyses of individual patient data from each trial.

Results

For lasmiditan 100 and 200 mg, in phase 2, the incidence of ≥1 AE was 72‐86% (26% severe), while in phase 3 was 36‐43% (2% severe). The most common AEs in all studies were CNS‐related. The phase 2 consent form was more descriptive of AEs than phase 3. In phase 2, patients recorded AEs and severity in a paper diary that warned about drowsiness and dizziness. In phase 3, patients recorded in electronic diaries whether they experienced unusual feelings after dosing with lasmiditan that they had not felt with a migraine before, and were contacted to determine if an AE had occurred. In phase 2, the AE Schwindel was variably translated from German as “vertigo” or “dizziness,” while phase 3 vertigo cases were queried to ensure there was a sensation of rotation or movement. History of recurrent dizziness and/or vertigo was exclusionary in phase 3.

Conclusions

This work illustrates how informed consent wording, AE collection methods, translation, exclusion criteria, and other factors may be important determinants for reporting of the frequency and severity of AEs in clinical trials.

Pavlovian Conditioning of Immunological and Neuroendocrine Functions

The phenomenon of behaviorally conditioned immunological and neuroendocrine functions has been investigated for the past 100 yr. The observation that associative learning processes can modify peripheral immune functions was first reported and investigated by Ivan Petrovic Pavlov and his co-workers. Their work later fell into oblivion, also because so little was known about the immune system’s function and even less about the underlying mechanisms of how learning, a central nervous system activity, could affect peripheral immune responses. With the employment of a taste-avoidance paradigm in rats, this phenomenon was rediscovered 45 yr ago as one of the most fascinating examples of the reciprocal functional interaction between behavior, the brain, and peripheral immune functions, and it established psychoneuroimmunology as a new research field. Relying on growing knowledge about efferent and afferent communication pathways between the brain, neuroendocrine system, primary and secondary immune organs, and immunocompetent cells, experimental animal studies demonstrate that cellular and humoral immune and neuroendocrine functions can be modulated via associative learning protocols. These (from the classical perspective) learned immune responses are clinically relevant, since they affect the development and progression of immune-related diseases and, more importantly, are also inducible in humans. The increased knowledge about the neuropsychological machinery steering learning and memory processes together with recent insight into the mechanisms mediating placebo responses provide fascinating perspectives to exploit these learned immune and neuroendocrine responses as supportive therapies, the aim being to reduce the amount of medication required, diminishing unwanted drug side effects while maximizing the therapeutic effect for the patient’s benefit.

Childhood Trauma, Emotion Regulation, and Pain in Individuals With Alcohol Use Disorder

Introduction: Several studies have confirmed that the experience of childhood trauma, poor emotion regulation, as well as the experience of physical pain may contribute to the development and poor treatment outcomes of alcohol use disorder (AUD). However, little is known about how the joint impact of these experiences may contribute to AUD. Objectives: To analyze associations between childhood trauma, emotion regulation, and pain in individuals with AUD. Methods: The study sample included 165 individuals diagnosed with AUD. The Childhood Trauma Questionnaire (CTQ) was used to investigate different types of trauma during childhood (physical, emotional, and sexual abuse and neglect), the Brief Symptom Inventory was used to assess anxiety symptoms, the Difficulties in Emotion Regulation Scale (DERS) was used to assess emotional dysregulation, and the Pain Resilience Scale and Pain Sensitivity Questionnaire were used to measure self-reported pain tolerance and sensitivity. Results: Childhood emotional abuse (CTQ subscale score) was positively associated with anxiety, anxiety was positively associated with emotional dysregulation, and emotional dysregulation was negatively associated with pain tolerance. Accordingly, there was support for a significant indirect negative association between childhood emotional abuse and pain tolerance. The serial mediation statistical procedure demonstrated that anxiety and emotional dysregulation mediated the effect of childhood emotional abuse on pain resilience among individuals with AUD. Conclusions: Targeting emotional dysregulation and physical pain that can result from childhood trauma may have particular therapeutic utility among individuals treated for AUD.

The Clinical Implications of Nocebo Effects for Biosimilar Therapy

Nocebo effects encompass negative responses to inert interventions in the research setting and negative outcomes with active treatments in the clinical research or practice settings, including new or worsening symptoms and adverse events, stemming from patients' negative expectations and not the pharmacologic action of the treatment itself. Numerous personality, psychosocial, neurobiological, and contextual/environmental factors contribute to the development of nocebo effects, which can impair quality of life and reduce adherence to treatment. Biologics are effective agents widely used in autoimmune disease, but their high cost may limit access for patients. Biosimilar products have gained regulatory approval based on quality, safety, and efficacy comparable to that of originator biologics in rigorous study programs. In this review, we identified gaps in patients' and healthcare professionals' awareness, understanding, and perceptions of biosimilars that may result in negative expectations and nocebo effects, and may diminish their acceptance and clinical benefits. We also examined features of nocebo effects with biosimilar treatment that inform research and clinical practices. Namely, when biosimilars are introduced to patients as possible treatment options, we recommend adoption of nocebo-reducing strategies to avoid negative expectations, including delivery of balanced information on risk-benefit profiles, framing information to focus on positive attributes, and promoting shared decision-making processes along with patient empowerment. Healthcare professionals confident in their knowledge of biosimilars and aware of bias-inducing factors may help reduce the risk of nocebo effects and improve patients' adherence in proposing biosimilars as treatment for autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease.

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.

Placebo Effects on the Neurologic Pain Signature: A Meta-analysis of Individual Participant Functional Magnetic Resonance Imaging Data

Importance

Placebo effects reduce pain and contribute to clinical analgesia, but after decades of research, it remains unclear whether placebo treatments mainly affect nociceptive processes or other processes associated with pain evaluation.

Objective

We conducted a systematic, participant-level meta-analysis to test the effect of placebo treatments on pain-associated functional neuroimaging responses in the neurologic pain signature (NPS), a multivariate brain pattern tracking nociceptive pain.

Data Sources

Medline (PubMed) was searched from inception to May 2015; the search was augmented with results from previous meta-analyses and expert recommendations.

Study Selection

Eligible studies were original investigations that were published in English in peer-reviewed journals and that involved functional neuroimaging of the human brain with evoked pain delivered under stimulus intensity-matched placebo and control conditions. The authors of all eligible studies were contacted and asked to provide single-participant data.

Data Extraction and Synthesis

Data were collected between December 2015 and November 2017 following the Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data guidelines. Results were summarized across participants and studies in a random-effects model.

Main Outcomes and Measures

The main, a priori outcome was NPS response; pain reports were assessed as a secondary outcome.

Results

We obtained data from 20 of 28 identified eligible studies, resulting in a total sample size of 603 healthy individuals. The NPS responses to painful stimulation compared with baseline conditions were positive in 575 participants (95.4%), with a very large effect size (g = 2.30 [95% CI, 1.92 to 2.69]), confirming its sensitivity to nociceptive pain in this sample. Placebo treatments showed significant behavioral outcomes on pain ratings in 17 of 20 studies (85%) and in the combined sample (g = -0.66 [95% CI, -0.80 to -0.53]). However, placebo effects on the NPS response were significant in only 3 of 20 studies (15%) and were very small in the combined sample (g = -0.08 [95% CI, -0.15 to -0.01]). Similarly, analyses restricted to studies with low risk of bias (g = -0.07 [95% CI, -0.15 to 0.00]) indicated very small effects, and analyses of just placebo responders (g = -0.22 [95% CI, -0.34 to -0.11]) indicated small effects, as well.

Conclusions and Relevance

Placebo treatments have moderate analgesic effects on pain reports. The very small effects on NPS, a validated measure that tracks levels of nociceptive pain, indicate that placebo treatments affect pain via brain mechanisms largely independent of effects on bottom-up nociceptive processing.

Schwerdtfeger A. Das Angstbewältigungsinventar für medizinische Situationen (ABI-MS)

Zusammenfassung. Das „Angstbewältigungsinventar für medizinische Situationen“ (ABI-MS) ist ein Situations-Reaktions-Inventar, das habituelle Präferenzen für den Einsatz kognitiv vermeidender und vigilanter Bewältigungsstrategien in potenziell bedrohlichen medizinischen Kontexten messen soll. Im ABI-MS, das sich konzeptuell und methodisch an das Angstbewältigungs-Inventar (ABI; Krohne & Egloff, 1999 ) anlehnt, werden 4 Szenarien vorgegeben (Blutabnahme, Schnittwunde, Darmspiegelung und Narkose), in die sich die Personen hineinversetzen sollen. Zu jedem Szenario werden jeweils 4 kognitiv vermeidende und 4 vigilante Reaktionsoptionen gegeben, deren Zutreffen die Personen beurteilen. In der vorliegenden Untersuchung wurden Struktur und psychometrische Qualität des ABI-MS geprüft. Konfirmatorische Faktorenanalysen ( N = 2 131) auf der Basis des Zwei-Parameter Logistischen Item-Response-Modells bestätigen die Annahme zweier situationsübergreifender Faktoren der Angstbewältigung in medizinischen Kontexten. Das Inventar erreicht zufriedenstellende Reliabilitäten. Eine Retest-Untersuchung belegt, dass primär habituelle Präferenzen erfasst werden. Korrelationen mit Verfahren zur Messung von Angstbewältigung und Persönlichkeitseigenschaften geben Hinweise auf die konvergente und diskriminante Validität des ABI-MS.

When Expectancies Are Violated: A Functional Magnetic Resonance Imaging Study

Positive and negative expectancies drive behavioral and neurobiological placebo and nocebo effects, which in turn can have profound effects on patient improvement or worsening. However, expectations of events and outcomes are often not met in daily life and clinical practice. It is currently unknown how this affects placebo and nocebo effects. We have demonstrated that the violation of expectancies, such as when there is a discrepancy between what is expected and what is actually presented, reduces both placebo and nocebo effects while causing an extinction of placebo effects. The reduction of placebo and nocebo effects was paralleled by an activation of the left inferior parietal cortex, a brain region that redirects attention when discrepancies between sensory and cognitive events occur. Our findings highlight the importance of expectancy violation in shaping placebo and nocebo effects and open up new avenues for managing positive and negative expectations in clinical trials and practices.

Composite Pain Biomarker Signatures for Objective Assessment and Effective Treatment

Pain is a subjective sensory experience that can, mostly, be reported but cannot be directly measured or quantified. Nevertheless, a suite of biomarkers related to mechanisms, neural activity, and susceptibility offer the possibility-especially when used in combination-to produce objective pain-related indicators with the specificity and sensitivity required for diagnosis and for evaluation of risk of developing pain and of analgesic efficacy. Such composite biomarkers will also provide improved understanding of pain pathophysiology.

Pain, placebo, and test of treatment efficacy: a narrative review

Over the past decade, the mechanisms underlying placebo effects have begun to be identified. At the same time, the placebo response appears to have increased in pharmacological trials and marked placebo effects are found in neurostimulation and surgical trials, thereby posing the question whether non-pharmacological interventions should be placebo-controlled to a greater extent. In this narrative review we discuss how the knowledge of placebo mechanisms may help to improve placebo control in pharmacological and non-pharmacological trials. We review the psychological, neurobiological, and genetic mechanisms underlying placebo analgesia and outline the current problems and potential solutions to the challenges with placebo control in trials on pharmacological, neurostimulation, and surgical interventions. We particularly focus on how patients' perception of the therapeutic intervention, and their expectations towards treatment efficacy may help develop more precise placebo controls and blinding procedures and account for the contribution of placebo factors to the efficacy of active treatments. Finally, we discuss how systematic investigations into placebo mechanisms across various pain conditions and types of treatment are needed in order to 'personalise' the placebo control to the specific pathophysiology and interventions, which may ultimately lead to identification of more effective treatment for pain patients. In conclusion this review shows that it is important to understand how patients' perception and expectations influence the efficacy of active and placebo treatments in order to improve the test of new treatments. Importantly, this applies not only to assessment of drug efficacy but also to non-pharmacological trials on surgeries and stimulation procedures.

The sensory and affective components of pain: are they differentially modifiable dimensions or inseparable aspects of a unitary experience? A systematic review

BACKGROUND

Pain is recognised to have both a sensory dimension (intensity) and an affective dimension (unpleasantness). Pain feels like a single unpleasant bodily experience, but investigations of human pain have long considered these two dimensions of pain to be separable and differentially modifiable. The evidence underpinning this separability and differential modifiability is seldom presented. We aimed to fill this gap by evaluating the current evidence base for whether or not the sensory and affective dimensions of pain can be selectively modulated using cognitive manipulations.

METHODS

A rigorous systematic search, based on a priori search terms and consultation with field experts, yielded 4270 articles. A detailed screening process was based on the following recommendations: (i) evaluation of effectiveness; (ii) examination of methodological rigour, including each study having an a priori intention to cognitively modulate one of the two dimensions of pain; and (iii) sound theoretical reasoning. These were used to ensure that included studies definitively answered the research question.

RESULTS

After in-depth critique of all 12 articles that met the inclusion criteria, we found that there is no compelling evidence that the sensory and affective dimensions of pain can be selectively and intentionally modulated using cognitive manipulations in humans.

CONCLUSIONS

We offer potential explanations for this discrepancy between assumptions and evidence and contend that this finding highlights several important questions for the field, from both the research and clinical perspectives.

The role of hedonics in the Human Affectome

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.

It is not just the drugs that matter: the nocebo effect

The role of psychological mechanisms in the treatment process cannot be underestimated, the well-known placebo effect unquestionably being a factor in treatment. However, there is also a dark side to the impact of mental processes on health/illness as exemplified by the nocebo effect. This phenomenon includes the emergence or exacerbation of negative symptoms associated with the therapy, but arising as a result of the patient's expectations, rather than being an actual complication of treatment. The exact biological mechanisms of this process are not known, but cholecystokinergic and dopaminergic systems, changes in the HPA axis, and the endogenous secretion of opioids are thought to be involved. The nocebo effect can affect a significant proportion of people undergoing treatment, including cancer patients, leading in some cases to the cessation of potentially effective therapy, because of adverse effects that are not actually part of the biological effect of treatment. In extreme cases, as a result of suggestions and expectations, a paradoxical effect, biologically opposite to the mechanism of the action of the drug, may occur. In addition, the nocebo effect may significantly interfere with the results of clinical trials, being the cause of a significant proportion of complications reported. Knowledge of the phenomenon is thus necessary in order to facilitate its minimalization and thus improve the quality of life of patients and the effectiveness of treatment.

A test of psychological and electrodermal changes immediately after the delivery of 3 analgesic treatment messages

Introduction:

Placebo analgesia often results when a pain reduction treatment message is delivered to a patient or research participant. Little information exists regarding the psychological changes that are immediately triggered by the delivery of a treatment message.

Objectives:

This experiment tested the impact of 3 different analgesic treatment messages on the expectations, feelings, and electrodermal activity of participants anticipating a pain stimulus.

Methods:

In laboratory sessions, healthy participants (N = 138) were randomly assigned to 1 of 4 conditions in a between-subject design. The design included a no treatment message control condition and 3 treatment message conditions: a standard analgesic message, an analgesic treatment with side-effect message, and a double-blind analgesic message. After the treatment message manipulation, measures were taken of: treatment efficacy expectations, pain experience expectations, pretask anxiety, positive affect, negative affect, and electrodermal activity.

Results:

Overall, the dependent measures showed relatively few correlations. Furthermore, across all 3 message conditions, treatment-specific expectations were greatly increased compared with the control condition. Finally, participants in the double-blind message condition displayed elevated negative affect.

Conclusion:

All 3 analgesic treatment messages produced a stronger immediate influence on treatment efficacy expectations than on the other dependent measures. Treatment messages can alter negative affect along with expectancies. The low correlations found between dependent measures suggest that different patterns of psychological responses may emerge from analgesic treatment messages depending on contextual factors.

Acute postoperative opioid consumption trajectories and long-term outcomes in pediatric patients after spine surgery

Background: The days following surgery are a critical period where the use of opioids predicts long-term outcomes in adults. It is currently unknown as to whether opioid consumption throughout the acute postoperative period is associated with long-term outcomes in pediatric patients. The aims of this study were to characterize opioid consumption trajectories in the acute postoperative period, identify predictors of trajectory membership and determine associations between opioid consumption trajectories and long-term patient outcomes.

Materials and methods: Medication use, pain and mental health status were assessed at baseline in adolescents with idiopathic scoliosis who were scheduled for spinal fusion surgery. Cumulative 6-hr opioid consumption was recorded for up to 5 days after spinal surgery. At 6 months after surgery, medication use, pain and functional activity were evaluated. Growth mixture modeling was used to identify opioid trajectories.

Results: One hundred and six patients were included in the study. Mean cumulative 6-hr opioid consumption in the acute postoperative period was 13.23±5.20 mg/kg. The model with the best fit contained 5 acute postoperative trajectories and a quadratic term (AIC =6703.26, BIC =6767.19). Two types of patient behaviors were identified: high opioid consumers (trajectories 4 and 5) and low opioid consumers (trajectories 1, 2 and 3). Intraoperative intrathecal morphine dose was a predictor of trajectory membership (p=0.0498). Opioid consumption during the acute postoperative period was not significantly associated with pain, functional activity or pain medication use at 6 months after surgery.

Conclusion: In pediatric patients, intraoperative intrathecal morphine dose predicts opioid consumption in the acute postoperative period. Importantly, opioid consumption during this period does not affect long-term outcomes in pediatric patients after a spine surgery.

Is placebo analgesia for heat pain a sensory effect? An exploratory study on minimizing the influence of response bias

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We explored whether placebo analgesia alters afferent nociceptive processing.

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Healthy adult participants received a standard heat placebo induction procedure.

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Placebo manipulation was modified to reduce experimenter demand.

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A novel inter-arm sensory discrimination task was administered.

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Only placebo responders showed changes in discriminative ability.

We explored the ongoing question of whether placebo analgesia alters afferent nociceptive processing in a novel paradigm designed to minimize the role of response bias in placebo measurement. First, healthy adult participants received a standard heat placebo induction and conditioning procedure using a topical “analgesic” cream applied to one arm. During a subsequent placebo testing procedure, participants rated stimuli on the placebo-treated arm and untreated arm, using a task that minimized subjects’ ability to guess the expected response, thus reducing experimenter demand. Retrospectively participants reported moderate analgesia effectiveness (mean = 5.3/10), but for individual temperature ratings, only 2 subjects exhibited a perceptual placebo response >5 points. Next, these subjects completed a novel, exploratory task designed to measure changes in inter-arm in discriminative accuracy that would be expected from changes in afferent nociception. Both placebo responders (but no non-responders) showed reduced discriminative ability when the hotter stimulus occurred on the placebo arm, an effect consistent with alterations in nociceptive afferent flow and unlikely to be caused by response bias.

Placebo analgesia effects across central nervous system diseases: what do we know and where do we need to go?

Placebo effects are well established in healthy participants experiencing experimental or acute pain. Yet, little is known about the mechanisms of placebo analgesia effects in patients with chronic pain and even less is known in patients suffering from central nervous system (CNS) diseases where pain is prevalent, difficult to manage, and often undertreated. This article briefly reviews the current knowledge of placebo analgesia effects in healthy participants with the aim of discussing how the mechanisms in placebo analgesia differ between healthy participants and patients. The focus will be on placebo analgesia effects in chronic pain conditions as well as in 2 CNS diseases: Alzheimer disease and Parkinson disease. Finally, strengths and weaknesses of the current knowledge will be discussed and it will be demonstrated how insights from the placebo literature may point to new ways of improving treatments among patients experiencing pain in relation to CNS diseases.

Lipödem – Mythen und Fakten Teil 4

Um das Lipödem ranken sich zahlreiche Mythen! In diesem vierten Beitrag unserer Artikelserie setzen wir uns mit dem Stellenwert der Liposuktion beim Lipödem auseinander. Wir diskutieren das von vielen die Liposuktion durchführenden Ärzten verbreitete Statement: „Die Liposuktion führt zu ausgeprägter und dauerhafter Verbesserung des Lipödems“. Wir konnten zeigen, dass zwischen den oft euphorischen Versprechungen der chirurgisch tätigen Kollegen und der aktuellen Studienlage zur Liposuktion eine erhebliche Lücke klafft. Sowohl Studienqualität als auch Studiensetting weisen erhebliche Mängel auf, Mängel, die Zweifel an diesem verbreiteten Statement aufkommen lassen. Eine ähnliche Lücke klafft darüber hinaus zwischen den Empfehlungen der S1-Leitlinie Lipödem und der tatsächlichen „Absaugpraxis“ bei adipösen Lipödempatientinnen. Die in den Leitlinien empfohlene „kritische Indikationsstellung“ bei gleichzeitigem Auftreten von Lipödem und Adipositas findet kaum Gehör. Es kann daher nicht genug betont werden, dass Liposuktion keine Methode ist, um Adipositas zu behandeln. Gleichwohl kann die Liposuktion durchaus zu einer Verbesserung des Lipödems beitragen. Entscheidend für den Therapieerfolg ist die Auswahl der Patientinnen, die aufgrund – medizinischer – Kriterien erfolgen muss. Darüber sollte die Liposuktion in ein Gesamtkonzept eingebunden werden, welches psychosoziale, ernährungs- und sportmedizinische Gesichtspunkte berücksichtigt.

Morphine effects within the rodent anterior cingulate cortex and rostral ventromedial medulla reveal separable modulation of affective and sensory qualities of acute or chronic pain

Modulation of pain may result from engagement of opioid receptors in multiple brain regions. Whether sensory and affective qualities of pain are differentially affected by brain opioid receptor circuits remains unclear. We previously reported that opioid actions within the rostral anterior cingulate cortex (ACC) produce selective modulation of affective qualities of neuropathic pain in rodents, but whether such effects may occur in other areas of the ACC is not known. Here, morphine was microinjected into 3 regions of the ACC or into the rostral ventromedial medulla (RVM), and pain behaviors in naive, sham, or spinal nerve ligated (SNL) rats were evaluated. In naive animals, the tail-flick response was inhibited by RVM, but not ACC, morphine. Anterior cingulate cortex morphine did not affect tactile allodynia (the von Frey test) or mechanical (Randall-Selitto) or thermal (Hargreaves) hyperalgesia in spinal nerve ligated rats. In contrary, RVM morphine reduced tactile allodynia and produced both antihyperalgesic and analgesic effects against mechanical and thermal stimuli as well as conditioned place preference selectively in nerve-injured rats. Within the RVM, opioids inhibit nociceptive transmission reflected in both withdrawal thresholds and affective pain behaviors. Activation of mu opioid receptors within specific rostral ACC circuits, however, selectively modulates affective dimensions of ongoing pain without altering withdrawal behaviors. These data suggest that RVM and ACC opioid circuits differentially modulate sensory and affective qualities of pain, allowing for optimal behaviors that promote escape and survival. Targeting specific ACC opioid circuits may allow for treatment of chronic pain while preserving the physiological function of acute pain.

Efficacious transition from reference infliximab to biosimilar infliximab in clinical practice

OBJECTIVES

To evaluate the transition from reference infliximab Remicade to biosimilar Remsima in patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA).

METHODS

Patients were informed through a letter about the transition to a biosimilar and were subsequently contacted for possible additional questions and whether they agreed upon the transition. Once agreed, Remsima was administered at the same dosage and interval as previous treatment with Remicade. Data on the transition were analyzed in January 2018. The primary outcome was the percentage of patients continuing treatment with Remsima and secondary outcome was the change in disease activity measured with the Disease Activity Score in 28 joints using erythrocyte sedimentation rate (DAS28-ESR). In addition, the reasons for discontinuation with infliximab or restarting Remicade were recorded.

RESULTS

In total 47 patients were approached, 45 patients switched from Remicade to Remsima, two patients disagreed upon transition and continued Remicade. At the end of the follow-up period of 2 years, 39 patients (87%) continued with Remsima, three patients (7%) restarted Remicade due to inefficacy according to the patient (this was not objectified by the rheumatologist) 2 (4%) patients switched to another biological due to lack of effect and in one patient (2%) infliximab was stopped because of lung malignancy. Furthermore, the DAS28-ESR remained comparable before and after the switch, with a mean (SD) of 2.34 (±1.02) and 2.31 (±1.11) respectively.

CONCLUSION

In our population, 87% of patients continued Remsima during the follow-up period of approximately 2 years. Three patients restarted Remicade, while retaining stable DAS28-ESR.

Contralateral segmental transcutaneous electrical nerve stimulation inhibits nociceptive flexion reflex in healthy participants

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a non-invasive treatment to relieve pain. Contralateral TENS (i.e. TENS administered to the contralateral side of a painful body part) is beneficial when TENS cannot be directly applied to pain site, such as in cases of trauma. Although TENS produces segmental analgesia in an ipsilateral limb, it has been unclear whether TENS produces higher analgesic effects in the contralateral segmental area. The aim of the present study was to investigate the analgesic effects of TENS in contralateral segmental or extra-segmental areas on physiological and subjective pain outcomes, using a nociceptive flexion reflex (NFR) method.

METHODS

We randomly allocated 60 healthy participants to three groups: contralateral segmental TENS (CS-TENS); contralateral extra-segmental TENS (CE-TENS); and contralateral placebo TENS (CP-TENS). CS-TENS was applied to right superficial sural nerve and CE-TENS was applied to the right superficial femoral nerve, each for 30 minutes. The magnitude of the NFR elicited by electrical stimulation of the left sural nerve was measured at baseline and at three subsequent 10-minute intervals. Subjective pain intensity was measured simultaneously with a visual analogue scale (VAS).

RESULTS

At 30 min, the NFR magnitude of CS-TENS group was significantly lower than that of the CP-TENS group (p = 0.021). There were no significant differences in VAS scores among the groups at any time point.

CONCLUSIONS

Our findings suggest that CS-TENS inhibited NFR. Although there was no significant between-group difference in subjective pain intensity, factors such as a placebo effect probably impacted it.

SIGNIFICANCE

Our findings provide support for the contralateral approach at stimulation sites when TENS cannot be directly administered to a pain site (e.g. due to disease or trauma).

Biosimilars for inflammatory bowel disease: how can healthcare professionals help address patients' concerns?

The patent expiration of some biologics used in chronic conditions such as inflammatory bowel disease (IBD) has led to the development of biosimilar monoclonal antibodies. The tailored regulatory approval route for biosimilar development ensures that approved biosimilars show similarity to their originators in terms of efficacy and safety, and avoids unnecessary repetition of clinical trials carried out with the originator product. However, some patients may still have concerns about using biosimilars and it is the responsibility of healthcare professionals (HCPs) to alleviate these concerns. Areas covered: This review highlights clinical and real-world evidence supporting efficacy and safety of biosimilars in patients with IBD. Moreover, based on international surveys, potential patient concerns are highlighted, along with possible actions HCPs can take to address these concerns. Expert commentary: The rising use of biosimilars in IBD is expected to have a positive impact on the availability of biologics and healthcare costs. Several biosimilars have been approved for use and more are likely to come to the market in the future; however, transitioning patients to biosimilars could pose an unexpected challenge without the help and support of HCPs.

Psychobiological Mechanisms of Placebo and Nocebo Effects: Pathways to Improve Treatments and Reduce Side Effects

Placebo effects constitute a major part of treatment success in medical interventions. The nocebo effect also has a major impact, as it accounts for a significant proportion of the reported side effects for many treatments. Historically, clinical trials have aimed to reduce placebo effects; however, currently, there is interest in optimizing placebo effects to improve existing treatments and in examining ways to minimize nocebo effects to improve clinical outcome. To achieve these aims, a better understanding of the psychological and neurobiological mechanisms of the placebo and nocebo response is required. This review discusses the impact of the placebo and nocebo response in health care. We also examine the mechanisms involved in the placebo and nocebo effects, including the central mechanism of expectations. Finally, we examine ways to enhance placebo effects and reduce the impact of the nocebo response in clinical practice and suggest areas for future research.