Placebo effects: from the neurobiological paradigm to translational implications

Warm-up plus verbal communications administered as placebo procedure during the training session improves running performance

The aim of this study was to investigate the effects on running performance of a within-session placebo procedure consisting of a conditioning treatment plus verbal communications. Twenty-six subjects were assigned to PLACEBO and CONTROL groups. Participants performed three sessions: Session 1-Cooper Test, Session 2-Baseline session and Session 3-Experimental session. During Session 2, participants performed a sprint-interval-training (SIT)-until-exhaustion preceded by a general warm-up, while in Session3 the SIT was preceded by a conditioning treatment (FIFA11+ warm-up), known to be effective in preventing injuries but not improving performance. Moreover, in Session3, only the PLACEBO group received verbal suggestions (before the warm-up) to influence participants' expectations about FIFA11+ effectiveness in improving performance, and deceptive feedback (during each SIT recovery bout) to increase the conditioning effect. To evaluate performance improvements, Running Time was chosen as a main outcome while to ensure participants reached exhaustion, physiological and metabolic responses were monitored. Total running distance (TRD) was also measured. Results showed that, Running Time and TRD significantly increased in the PLACEBO group whilst no differences in the CONTROL group were observed thus, suggesting the effectiveness of the within-session-placebo procedure in improving running performance. These findings shed a new light on the interaction between cognitive domain and performance, thus encouraging coaches to adopt this innovative method during the training protocol to enhance athletes' performance. Moreover, this placebo procedure, not requiring additional time, tools or resources, could represent a more ecological approach that can be easily adopted in the field.

Enhancing placebo analgesia: Unravelling the powerful interplay of ownership and verbal suggestion

BACKGROUND

Placebo analgesic research demonstrates pain reduction after using a placebo analgesic. Recent studies have documented that sometimes possessing a placebo analgesic induces placebo analgesia. These prior studies used a 'cream' as the stimulus and proposed that the effect is driven by an expectancy of obtaining benefits from the owned analgesic. This paper examines three pivotal components of placebo analgesia: placebo form, ownership and expectancy induced by verbal suggestion. We investigate analgesic expectancy between cream versus oil form of placebo stimulus and systematically isolate the effects of ownership, verbal suggestion and their interaction, comparing with the effect of use, to decipher the dynamics of placebo analgesia.

METHODS

Study 1 (N = 46) evaluated analgesic expectancy between cream and oil. Study 2 (N = 119) exposed participants to a placebo analgesic oil and randomized them into PU (possess and use), PA (possess and anticipate), P (possess-only) or A (anticipate-only) conditions. Pain outcomes were assessed using a cold pressor test. Comparing PA and P conditions assessed the verbal suggestion effect, comparing PA and A conditions evaluated the possession effect, while comparing PU and PA conditions shed light on the use effect.

RESULTS

In Study 1, participants showed comparable analgesic expectancy for cream and oil. In Study 2, both PA and PU groups performed equally well, reporting higher pain threshold, F(3, 115) = 5.14, p = 0.002,η p 2 $$ {\eta}_p^2 $$  = 0.12; and a greater probability of persistent hand submersion than P and A groups, X2(3) = 8.06, p = 0.045.

CONCLUSION

The findings highlight the significance of integrating possession with expectancy to induce placebo analgesia, which has clinical implications.

SIGNIFICANCE

This study delves into the intricate dynamics of placebo analgesia, shedding light on the significant influence of ownership and verbal suggestion. Through a meticulous exploration of the relationship between ownership and expectancy induced by verbal suggestion, we propose novel avenues for enhancing placebo responses. This research has implications for clinical practice and pain management strategies, potentially revolutionizing approaches to pain relief and therapeutic outcomes. Our findings contribute to a paradigm shift in understanding placebo analgesia, emphasizing the pivotal interaction between ownership and verbal suggestion.

Heart is deceitful above all things: Threat expectancy induces the illusory perception of increased heartrate

It has been suggested that our perception of the internal milieu, or the body's internal state, is shaped by our beliefs and previous knowledge about the body's expected state, rather than being solely based on actual interoceptive experiences. This study investigated whether heartbeat perception could be illusorily distorted towards prior subjective beliefs, such that threat expectations suffice to induce a misperception of heartbeat frequency. Participants were instructed to focus on their cardiac activity and report their heartbeat, either tapping along to it (Experiment 1) or silently counting (Experiment 2) while ECG was recorded. While completing this task, different cues provided valid predictive information about the intensity of an upcoming cutaneous stimulation (high- vs. low- pain). Results showed that participants expected a heart rate increase over the anticipation of high- vs. low-pain stimuli and that this belief was perceptually instantiated, as suggested by their interoceptive reports. Importantly, the perceived increase was not mirrored by the real heart rate. Perceptual modulations were absent when participants executed the same task but with an exteroceptive stimulus (Experiment 3). The findings reveal, for the first time, an interoceptive illusion of increased heartbeats elicited by threat expectancy and shed new light on interoceptive processes through the lenses of Bayesian predictive processes, providing tantalizing insights into how such illusory phenomena may intersect with the recognition and regulation of people's internal states.

Translating knowledge on placebo and nocebo effects into clinical practice

Introduction

Positive and negative treatment expectations are powerful modulators of health and treatment outcomes. A substantial part of treatment success is due to contextual factors modulating patient's expectations towards a treatment. Consequently, treatment expectations should be a target of therapeutic interventions themselves.

Objectives

This article highlights the neurobiological underpinnings of treatment expectations as well as strategies to modulate contextual factors to optimize treatment outcomes in daily clinical settings.

Methods

This clinical update aligns with the 2022 IASP Global Year Translating Pain Knowledge into Practice and selectively reviews the best available evidence and practice.

Results

The effects of treatment expectations, also known as placebo and nocebo effects, are observed in various clinical conditions and physiological systems. However, most of our knowledge comes from the field of pain, where expectation effects substantially contribute to overall analgesic treatment outcomes. Experimental placebo analgesia paradigms provide the best illustration of how analgesic effects can be attributed not only to a pharmacological or specific treatment, but instead are the result of the expectation towards the treatment. The impact of expectations on treatment outcome is highly variable between individuals, and the identification of factors predicting an individual's response has proven to be challenging. Further research is required to provide personalized treatment strategies for the daily clinical practice.

Conclusion

Patient's previous experiences and expectations are powerful modulators of treatment efficacy, tolerability, and adherence. By providing a comprehensive overview of recent advances in this field, this review offers valuable insights for clinicians and researchers seeking to improve patient-clinician interaction.

The Placebo Effect on Tinnitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To quantify the placebo effect in randomized clinical trials treating tinnitus with oral or intratympanic placebo treatment.

DATA SOURCES

CINAHL, PubMed, and Scopus were searched for articles from conception to October 2022. MESH and key terms such as "tinnitus," "placebo," and "medication" were used to find randomized, placebo-controlled trials. The search was limited to articles in English.

METHODS

Randomized controlled trials with adult subjects evaluating tinnitus pretreatment and posttreatment with an oral or intratympanic medication versus a placebo arm were included. Crossover studies, studies involving middle/inner ear operations or devices, and studies that exclusively included nonidiopathic etiologies of tinnitus were excluded. Mean tinnitus symptom survey scores for the Tinnitus Handicap Inventory (THI), Tinnitus Severity Index, Tinnitus Functional Index, Tinnitus Handicap Questionnaire, and Visual Analog Scales for tinnitus Intensity/Loudness (VAS-L), Annoyance (VAS-An), and Awareness (VAS-Aw) were extracted for both placebo and experimental groups.

RESULTS

953 studies were screened with 23 studies being included in the final analysis. Meta-analysis of mean difference (MD) was calculated using RevMan 5.4. MD between pretreatment and posttreatment THI scores of the placebo arms was 5.6 (95% confidence interval, 3.3-8.0; p < 0.001). MD between pretreatment and posttreatment VAS scores of the placebo groups for Loudness, Annoyance, and Awareness were 0.8 (0.0 to 1.6, p = 0.05), 0.2 (-0.2 to 0.5, p = 0.34), and 0.3 (-0.0 to 0.7, p = 0.08), respectively.

CONCLUSIONS

Placebo treatment has shown effectiveness in improving patient-reported evaluations of tinnitus when using some standardized metrics such as THI and VAS-L; however, the improvement is not as substantial as nonplacebo treatment.

Transcutaneous electrical nerve stimulation (TENS) versus sham TENS in adult ED patients with abdominal pain: A clinical trial

OBJECTIVE

There is a growing consensus that the risks of current pharmacologic analgesics warrant consideration of alternative modalities for acute and chronic pain control. The objective of this study was to evaluate the effectiveness of transcutaneous electrical nerve stimulation (TENS) in adult emergency department (ED) patients presenting with abdominal pain.

METHODS

We conducted a patient and observer blinded randomized controlled trial comparing TENS to sham TENS. The study was conducted at a large suburban academic ED. Patients with abdominal pain and a verbal numeric pain scale (VNS) of 5 or greater were randomized to TENS or sham TENS applied via 4 skin pads, one in each abdominal quadrant for 30 min. The primary outcome was change in pain scores 30 min after the intervention. Our study had 80% power to detect a between group difference of 1.5 points on the VNS.

RESULTS

81 patients were randomized to TENS (n = 41) or sham TENS (n = 40). Groups were similar in baseline characteristics. The mean (SD) reductions in pain scores were 1.9 (2.1) and 1.7 (2.6) in patients treated with TENS and sham TENS respectively (P = 0.81). Use of rescue medications in patients with treated with TENS and sham TENS was similar (49 vs 55% respectively, P = 0.66).

CONCLUSIONS

Application of TENS to the abdominal wall did not result in more effective pain relief than sham TENS in adult ED patients with abdominal pain.

Placebo stimulates neuroplasticity in depression: implications for clinical practice and research

Neither psychological nor neuroscientific investigations have been able to fully explain the paradox that placebo is designed to be inert in randomized controlled trials (RCTs), yet appears to be effective in evaluations of clinical interventions in all fields of medicine and alternative medicine. This article develops the Neuroplasticity Placebo Theory, which posits that neuroplasticity in fronto-limbic areas is the unifying factor in placebo response (seen in RCTs) and placebo effect (seen in clinical interventions) where it is not intended to be inert. Depression is the disorder that has the highest placebo response of any medical condition and has the greatest potential for understanding how placebos work: recent developments in understanding of the pathophysiology of depression suggest that fronto-limbic areas are sensitized in depression which is associated with a particularly strong placebo phenomenon. An innovative linkage is made between diverse areas of the psychology and the translational psychiatry literature to provide supportive evidence for the Neuroplasticity Placebo Theory. This is underpinned by neuro-radiological evidence of fronto-limbic change in the placebo arm of antidepressant trials. If placebo stimulates neuroplasticity in fronto-limbic areas in conditions other than depression - and results in a partially active treatment in other areas of medicine - there are far reaching consequences for the day-to-day use of placebo in clinical practice, the future design of RCTs in all clinical conditions, and existing unwarranted assertions about the efficacy of antidepressant medications. If fronto-limbic neuroplasticity is the common denominator in designating placebo as a partially active treatment, the terms placebo effect and placebo response should be replaced by the single term "placebo treatment."

Overcoming Methodological Challenges for Advancing Stem Cell Therapies in Parkinson's Disease

The quest for new and improved therapies for Parkinson's disease (PD) remains of paramount importance, despite previous trial failures. There is a current debate regarding the potential of stem cell research as a therapeutic approach for PD. The studies of dopaminergic fetal stem cells for PD treatment, their design, and the results of the initial surgical placebo-controlled trials were reviewed in this study. Some of the fundamental methodological challenges and possible strategies to resolve them were proposed. In this article, we argue that the most important impact lies in the proof-of-principle demonstrated by clinical trials for cell replacement strategies in reconstructing the human brain. While some researchers argue that the considerable technical challenges associated with cell therapies for PD warrant the discontinuation of further development using stem cells, we believe that the opposing viewpoints are instrumental in identifying a series of methodological misunderstandings. Here, we propose to expose key challenges to ensure the advancement of the field and unlock the potential of stem cell therapies in PD treatment. Overall, this review underscores the need for further research and innovation to overcome the hurdles in realizing the potential of stem cell-based therapies for PD.

Clinical Assessment of Preemptive Analgesia on Success of Pulpal Anesthesia and Postendodontic Pain in Children with Irreversible Pulpitis: A Randomized Comparative Study

Introduction

Optimal pain management of symptomatic pulpitis in formative years goes a long way in developing a positive dental attitude. Efforts should be made to increase the success of anesthesia, thus diminishing negative dental experiences. The aim of the study was to assess the efficacy of preemptive analgesia on the success of pulpal anesthesia following inferior alveolar nerve block (IANB) in children with symptomatic irreversible pulpitis and on reducing postendodontic pain.

Materials and methods

The research design was an in vivo, three-group, parallel, quadruple-blind study. A total of 75 patients were randomly allocated to one of the three groups-group I: ibuprofen, group II: combination of ibuprofen and paracetamol, and group III: multivitamin (placebo). Premedication was given 45 minutes before treatment, and patients received IANB in a standardized manner. Pain during pulpectomy was recorded using the face, legs, activity, cry, consolability (FLACC) scale and postoperatively using Wong-Baker's pain rating scale (WBPRS) at 4, 12, and 24 hours. Success was measured if the pain felt was of no or mild intensity.

Results

Success of IANB was 64% for ibuprofen, 72% for the combination group, and 40% for the placebo group, with no statistically significant difference between all groups (p = 0.06) on the FLACC scale. At 4 hours postoperatively, a significant difference (p = 0.02) was found among groups with more children experiencing no or mild pain in groups I and II and the highest number of rescue medications taken by the placebo group.

Conclusion

Ibuprofen and a combination of ibuprofen and acetaminophen as preemptive analgesics had no significant effect on the success rate of IANB, although it was effective in reducing pain at 4 hours postoperatively.

How to cite this article

Gori NA, Patel MC, Bhatt RK, et al. Clinical Assessment of Preemptive Analgesia on Success of Pulpal Anesthesia and Postendodontic Pain in Children with Irreversible Pulpitis: A Randomized Comparative Study. Int J Clin Pediatr Dent 2024;17(1):72-78.

Existence of Quantum Pharmacology in Sartans: Evidence in Isolated Rabbit Iliac Arteries

Quantum pharmacology introduces theoretical models to describe the possibility of ultra-high dilutions to produce biological effects, which may help to explain the placebo effect observed in hypertensive clinical trials. To determine this within physiology and to evaluate novel ARBs, we tested the ability of known angiotensin II receptor blockers (ARBs) (candesartan and telmisartan) used to treat hypertension and other cardiovascular diseases, as well as novel ARBs (benzimidazole-N-biphenyl tetrazole (ACC519T), benzimidazole-bis-N,N'-biphenyl tetrazole (ACC519T(2)) and 4-butyl-N,N0-bis[[20-2Htetrazol-5-yl)biphenyl-4-yl]methyl)imidazolium bromide (BV6(K+)2), and nirmatrelvir (the active ingredient in Paxlovid) to modulate vascular contraction in iliac rings from healthy male New Zealand White rabbits in responses to various vasopressors (angiotensin A, angiotensin II and phenylephrine). Additionally, the hemodynamic effect of ACC519T and telmisartan on mean arterial pressure in conscious rabbits was determined, while the ex vivo ability of BV6(K+)2 to activate angiotensin-converting enzyme-2 (ACE2) was also investigated. We show that commercially available and novel ARBs can modulate contraction responses at ultra-high dilutions to different vasopressors. ACC519T produced a dose-dependent reduction in rabbit mean arterial pressure while BV6(K+)2 significantly increased ACE2 metabolism. The ability of ARBs to inhibit contraction responses even at ultra-low concentrations provides evidence of the existence of quantum pharmacology. Furthermore, the ability of ACC519T and BV6(K+)2 to modulate blood pressure and ACE2 activity, respectively, indicates their therapeutic potential against hypertension.

Placebo and nocebo in the treatment of migraine: How much does real world effectiveness depend on contextual effects?

PURPOSE

Treatments in medicine impact individuals beyond their intended effects, due to phenomena such as the placebo and nocebo effects. The placebo effect arises from the positive expectation of a treatment being beneficial, while the nocebo effect stems from the negative expectation of a treatment causing harm. Both in real-world practice and clinical trials, treatments can lead to outcomes unrelated to their intended mechanism of action, which we categorize as placebo and nocebo responses. These responses, combined with the inherent fluctuation in a condition's natural progression, regression to the mean, and random comorbidities, make up a significant part of the therapeutic experience. Particularly in pain management, placebo and nocebo effects play a substantial role. By addressing modifiable contextual factors such as patient expectations, lifestyle choices, and the therapeutic relationship, healthcare providers can enhance the effectiveness of migraine treatments, paving the way for a more comprehensive, individualized approach to patient care. We must also consider non-modifiable factors like personal experiences, beliefs, and information from social media and the internet.

CONCLUSION

This review offers a summary of our current understanding of the placebo and nocebo effects in migraine management.

The relationship between expectancy, anxiety, and the nocebo effect: a systematic review and meta-analysis with recommendations for future research

Despite the theoretical prominence of expectancy and anxiety as potential mechanisms of the nocebo effect, not all studies measure expectancy and/or anxiety, and there are inconsistent findings among those that do. The present study sought to systematically review and meta-analyse available data to evaluate the relationship between expectancy, anxiety and the nocebo effect. The two key questions were: (1) whether nocebo manipulations influence expectancy and anxiety; and (2) whether expectancy and anxiety are associated with the subsequent nocebo effect. Fifty-nine independent studies (n = 3129) were identified via database searches to 1st August 2021. Nocebo manipulations reliably increased negative expectancy with a large effect (g = .837) and state anxiety with a small effect (g = .312). Changes in expectancy and state anxiety due to the nocebo manipulation were associated with larger nocebo effects (r = .376 and .234, respectively). However, there was no significant association between dispositional anxiety and the nocebo effect. These findings support theories that rely on situationally-induced expectancy and anxiety, but not dispositional anxiety, to explain nocebo effects. Importantly, being malleable, these findings suggest that interventions that target maladaptive negative expectancies and state anxiety could be beneficial for reducing the harm nocebo effects cause across health settings. Recommendations for future research are discussed.

Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review

OBJECTIVES

This review aimed to summarise the existing knowledge about placebo and nocebo effects associated with pharmacological interventions and their mechanisms.

DESIGN

Umbrella review, adopting the Assessment of Multiple Systematic Reviews 2 tool for critical appraisal.

DATA SOURCES

MEDLINE/PubMed, Scopus, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trial were searched in September 2022, without any time restriction, for systematic reviews, narrative reviews, original articles. Results were summarised through narrative synthesis, tables, 95% CI.

OUTCOME MEASURES

Mechanisms underlying placebo/nocebo effects and/or their effect sizes.

RESULTS

The databases search identified 372 studies, for a total of 158 312 participants, comprising 41 systematic reviews, 312 narrative reviews and 19 original articles. Seventy-three per cent of the examined systematic reviews were of high quality.Our findings revealed that mechanisms underlying placebo and/or nocebo effects have been characterised, at least in part, for: pain, non-noxious somatic sensation, Parkinson's disease, migraine, sleep disorders, intellectual disability, depression, anxiety, dementia, addiction, gynaecological disorders, attention-deficit hyperactivity disorder, immune and endocrine systems, cardiovascular and respiratory systems, gastrointestinal disorders, skin diseases, influenza and related vaccines, oncology, obesity, physical and cognitive performance. Their magnitude ranged from 0.08 to 2.01 (95% CI 0.37 to 0.89) for placebo effects and from 0.32 to 0.90 (95% CI 0.24 to 1.00) for nocebo effects.

CONCLUSIONS

This study provides a valuable tool for clinicians and researchers, identifying both results ready for clinical practice and gaps to address in the near future.

FUNDING

Università Cattolica del Sacro Cuore, Milan, Italy with the 'Finanziamento Ponte 2022' grant.

PROSPERO REGISTRATION NUMBER

CRD42023392281.

Functional connectivity modifications in monoaminergic circuits occur in fatigued MS patients treated with fampridine and amantadine

BACKGROUND

Monoaminergic network dysfunction may have a role in multiple sclerosis (MS) fatigue pathogenesis.

OBJECTIVE

To investigate modifications of fatigue severity and resting state (RS) functional connectivity (FC) in monoaminergic networks of 45 fatigued MS patients after different symptomatic treatments.

METHODS

Patients were randomly, blindly assigned to fampridine (n = 15), amantadine (n = 15) or placebo (n = 15) treatment and underwent clinical and 3T-MRI evaluations at baseline (t0) and week 4 (w4), i.e. after four weeks of treatment. Fifteen healthy controls (HC) were enrolled. Dopamine-, noradrenaline- and serotonin-related RS FC was assessed by PET-guided constrained independent component analysis.

RESULTS

At t0, MS patients showed widespread monoamine-related RS FC abnormalities. At w4, fatigue scores decreased in all groups (p = range < 0.001-0.002). Concomitantly, fampridine and amantadine patients showed increased insular RS FC in dopamine-related and noradrenaline-related networks (p < 0.001, uncorrected). Amantadine patients also showed increased RS FC of anterior cingulate cortex in dopamine-related and noradrenaline-related networks (p < 0.001, uncorrected). Placebo patients showed increased precuneus/middle cingulate RS FC in the noradrenaline-related network (p < 0.001, uncorrected). In fampridine and placebo patients, just tendencies towards correlations between RS FC and fatigue modifications were found.

CONCLUSIONS

In MS patients, specific RS FC modifications in PET-guided monoaminergic networks were observed, concomitantly with fatigue improvements following treatment.

TRIAL REGISTRATION NUMBER

EudraCT 2010-023678-38.

Placebo effects in osteoarthritis: implications for treatment and drug development

Osteoarthritis (OA) is the most common form of arthritis worldwide, affecting ~500 million people, yet there are no effective treatments to halt its progression. Without any structure-modifying agents, management of OA focuses on ameliorating pain and improving function. Treatment approaches typically have modest efficacy, and many patients have contraindications to recommended pharmacological treatments. Drug development for OA is hindered by the gradual and progressive nature of the disease and the targeting of established disease in clinical trials. Additionally, new medications for OA cannot receive regulatory approval without demonstrating improvements in both structure (pathological features of OA) and symptoms (reduced pain and/or improved function). In clinical trials, people with OA show high 'placebo responses', which hamper the ability to identify new effective treatments. Placebo responses refer to the individual variability in response to placebos given in the context of clinical trials and other settings. Placebo effects refer specifically to short-lasting improvements in symptoms that occur because of physiological changes. To mitigate the effects of the placebo phenomenon, we must first understand what it is, how it manifests, how to identify placebo responders in OA trials and how these insights can be used to improve clinical trials in OA. Leveraging placebo responses and effects in clinical practice might provide additional avenues to augment symptom management of OA.

How familiar are German dermatologists with placebo and nocebo effects and to what extent are these targeted in clinical practice: A survey within the dermatological community

BACKGROUND

Every medical treatment inevitably comprises not only physiological, but also psychological components, reflected by placebo and nocebo effects, which significantly affect treatment outcome. However, the extent of knowledge on the mechanisms steering placebo and nocebo effects in the dermatological community in Germany is currently unclear.

OBJECTIVES

To assess the state of knowledge about placebo and nocebo effects in the German dermatological community, to evaluate whether this knowledge is already being used in clinical practice, and to investigate whether German dermatologists are interested in learning more about the topic.

METHODS

German Dermatologists, the majority working in their own practice, were asked to fill in an online survey addressing the knowledge about placebo and nocebo effects and the feasibility of special techniques to enhance placebo and minimize nocebo effects within the clinical routine.

RESULTS

N = 154 complete (79%) or partial (21%) responses to the survey were recorded in the online database and included in the analysis. All participants reported to know what the placebo effect is and 59.7% (74/124) indicated that they already had experience with prescribing or recommending a treatment without active substances. In contrast, only 62.0% (80/129) stated to know what the nocebo effect is. Participants showed a rather superficial knowledge regarding placebo and nocebo mechanisms. The majority of participants (76.7%, 99/129) expressed their willingness to be further educated about the underlying mechanisms mediating placebo and nocebo effects and the possible application in clinical practice.

CONCLUSIONS

The current survey offers a so far unique insight into the state of knowledge of German dermatologists on placebo and nocebo effects. The results indicate a need for education about this topic. Encouragingly, however, German dermatologists considered communication strategies to maximize placebo and reduce nocebo effects and expressed motivation to be trained to implement these strategies in everyday clinical practice.

Placebos in pediatrics: A cross-sectional survey investigating physicians' perspectives

OBJECTIVE

Placebo responses are significantly higher in children than in adults, suggesting a potential underused treatment option in pediatric care. To facilitate the clinical translation of these beneficial effects, we explored physicians' current practice, opinions, knowledge, and likelihood of recommending placebos in the future.

METHODS

A cross-sectional web-based survey administered by REDCap was conducted at Boston Children's Hospital between October 2021 and March 2022. Physicians (n = 1157) were invited to participate through an email containing a link to a 23-item survey designed to assess physicians' attitudes and perceptions towards the clinical use of placebo in pediatrics.

RESULTS

From 207 (18%) returned surveys, 109 (9%) were fully completed. Most respondents (79%) believed that enhancing the therapeutic components that contribute to the placebo response may be a way of improving pediatric care. However, whereas most (62%) found placebo treatments permissible, only one-third reported recommending them. In pediatrics, placebos are typically introduced as a medicine that "might help" (43%). The most common treatments recommended to enhance placebo effects are physical therapy, vitamins, and over-the-counter analgesics. Physicians most frequently recommend placebos for occasional pain, headaches, and anxiety disorders. Finally, the great majority of physicians (87%) stated they would be more likely to recommend placebo treatments if there were safety and ethical guidelines for open-label placebos.

CONCLUSIONS

Placebo treatments seem permissible to physicians in pediatric care, but the development of safety and ethical guidelines may be necessary before physicians systematically incorporate the benefits of the placebo effect in pediatrics.

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.

Neural underpinnings of open-label placebo effects in emotional distress

While placebo effects are well-known, research in the last decade revealed intriguing effects that placebos may have beneficial effects even when given without deception. At first glance, this seems paradoxical, but several studies have reported improvements in pain, depression, or anxiety. However, it still remains unclear whether these results represent objective biological effects or simply a bias in response and what neural underpinnings are associated with the open-label placebo effects. In two studies, we address this gap by demonstrating that open-label placebos reduce self-reported emotional distress when viewing highly arousing negative pictures. This reduced emotional distress was associated with an activation of brain areas known to modulate affective states such as the periaqueductal gray, the bilateral anterior hippocampi, and the anterior cingulate cortex. We did not find any prefrontal brain activation. Furthermore, brain activation was not associated with expectation of effects. In contrast, we found that brain responses were linked to general belief in placebos. The results demonstrate that the neural mechanisms of open-label placebo effects are partly identical to the neurobiological underpinnings of conventional placebos, but our study also highlights important differences with respect to a missing engagement of prefrontal brain regions, suggesting that expectation of effects may play a less prominent role in open-label placebos.

Effects of Wearable Fitness Trackers and Activity Adequacy Mindsets on Affect, Behavior, and Health: Longitudinal Randomized Controlled Trial

BACKGROUND

There is some initial evidence suggesting that mindsets about the adequacy and health consequences of one's physical activity (activity adequacy mindsets [AAMs]) can shape physical activity behavior, health, and well-being. However, it is unknown how to leverage these mindsets using wearable technology and other interventions.

OBJECTIVE

This research examined how wearable fitness trackers and meta-mindset interventions influence AAMs, affect, behavior, and health.

METHODS

A total of 162 community-dwelling adults were recruited via flyers and web-based platforms (ie, Craigslist and Nextdoor; final sample size after attrition or exclusion of 45 participants). Participants received an Apple Watch (Apple Inc) to wear for 5 weeks, which was equipped with an app that recorded step count and could display a (potentially manipulated) step count on the watch face. After a baseline week of receiving no feedback about step count, participants were randomly assigned to 1 of 4 experimental groups: they received either accurate step count (reference group; 41/162, 25.3%), 40% deflated step count (40/162, 24.7%), 40% inflated step count (40/162, 24.7%), or accurate step count+a web-based meta-mindset intervention teaching participants the value of adopting more positive AAMs (41/162, 25.3%). Participants were blinded to the condition. Outcome measures were taken in the laboratory by an experimenter at the beginning and end of participation and via web-based surveys in between. Longitudinal analysis examined changes within the accurate step count condition from baseline to treatment and compared them with changes in the deflated step count, inflated step count, and meta-mindset conditions.

RESULTS

Participants receiving accurate step counts perceived their activity as more adequate and healthier, adopted a healthier diet, and experienced improved mental health (Patient-Reported Outcomes Measurement Information System [PROMIS]-29) and aerobic capacity but also reduced functional health (PROMIS-29; compared with their no-step-count baseline). Participants exposed to deflated step counts perceived their activity as more inadequate; ate more unhealthily; and experienced more negative affect, reduced self-esteem and mental health, and increased blood pressure and heart rate (compared with participants receiving accurate step counts). Inflated step counts did not change AAM or most other outcomes (compared with accurate step counts). Participants receiving the meta-mindset intervention experienced improved AAM, affect, functional health, and self-reported physical activity (compared with participants receiving accurate step counts only). Actual step count did not change in either condition.

CONCLUSIONS

AAMs--induced by trackers or adopted deliberately--can influence affect, behavior, and health independently of actual physical activity.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03939572; https://www.clinicaltrials.gov/ct2/show/NCT03939572.

[Placebo effects in analgesia : Influence of expectations on the efficacy and tolerability of analgesic treatment]

Expectations of patients influence the perception and neuronal processing of acute and chronic pain and modulate the effectiveness of analgesic treatment. The expectation of treatment is not only the most important determinant of placebo analgesia. Expectations of treatment also influence the efficacy and tolerability of "active" pharmacological and non-pharmacological treatment of pain. Recent insights into the psychological and neurobiological mechanisms underlying the clinically relevant effects of treatment expectations enable and call for the systematic integration and modulation of treatment expectations into analgesic treatment concepts. Such a strategy promises to optimize analgesic treatment and to prevent or reduce the burden of unwanted side effects and the misuse of analgesics, particularly of opioids. This review highlights the current concepts, recent achievements and also challenges and key open research questions.

Can Translational Social Neuroscience Research Offer Insights to Mitigate Structural Racism in the United States?

Social isolation and conflict due to structural racism may result in human suffering and loneliness across the life span. Given the rising prevalence of these problems in the United States, combined with disruptions experienced during the COVID-19 pandemic, the neurobiology of affiliative behaviors may offer practical solutions to the pressing challenges associated with structural racism. Controlled experiments across species demonstrate that social connections are critical to survival, although strengthening individual resilience is insufficient to address the magnitude and impact of structural racism. In contrast, the multilevel construct of social resilience, defined by the power of groups to cultivate, engage in, and sustain positive relationships that endure and recuperate from social adversities, offers unique insights that may have greater impact, reach, and durability than individual-level interventions. Here, we review putative social resilience-enhancing interventions and, when available, their biological mediators, with the hope to stimulate discovery of novel approaches to mitigate structural racism. We first explore the social neuroscience principles underlying psychotherapy and other psychiatric interventions. Then, we explore translational efforts across species to tailor treatments that increase social resilience, with context and cultural sensitivity in mind. Finally, we conclude with some practical future directions for understudied areas that may be essential for progress in biological psychiatry, including ethical ways to increase representation in research and developing social paradigms that inform dynamics toward or away from socially resilient outcomes.

Savor the flavor: A randomized double-blind study assessing taste-enhanced placebo analgesia in healthy volunteers

Placebo effects substantially contribute to analgesic treatment outcomes and might be leveraged to enhance gold-standard treatments. The taste of oral medications has been proposed to boost placebo effects. Here, we aimed at estimating how far the taste of an oral medication enhances placebo analgesia. We conducted a randomized, double-blind, between-group, single-visit study, with pre-treatment baseline. Over the course of three substudies, 318 healthy volunteers (297 included) were tested in a clinical trial setting. Participants were subjected to experimental tonic cold water pain (cold pressor test) before and after receiving taste-neutral (water), or bitter (quinine), or sweet (saccharin), or no placebo drops. Pre- versus post-treatment changes in area under the pain rating curve, the main outcome, indicated that placebo treatment showed a small analgesic effect versus no treatment. Added taste induced placebo enhancement in the very small effect size range, but accounted for a substantial portion of the overall placebo effect. No noteworthy advantage of sweet over bitter placebo was observed. An exploration of heart rate (HR) recordings indicated that placebo treatments were associated with an increase in peak HR-response to cold water, but these were not associated with placebo analgesia at an individual level. Placebo treatments were associated with minimal side effects. These results indicate that added taste may be an easy-to-implement, cost-effective, and safe way to optimize treatment outcomes and that taste-neutral preparations may reduce placebo-related outcome variance in clinical trials. Further studies are needed to test if these findings can be translated into clinical scenarios.

Feasibility of Using Detuned Laser as a Placebo In Manual Therapy Research: An Analysis of Participant Perceptions

OBJECTIVE

The purpose of this study was to determine the feasibility of using detuned laser as a placebo intervention in manual therapy research.

METHODS

We performed a secondary data analysis of a randomized controlled trial. In our analysis, 30 participants with chronic ankle instability (manual therapy group: n = 13, age = 33.1 ± 8.1 years, female participants = 50%; detuned laser group: n = 17, age = 31.9 ± 11.8 years, female participants = 72%) were asked to indicate which intervention (manual therapy [active] or detuned laser [placebo]), they thought they had received and to give a confidence rating on their response regarding the received intervention at the conclusion of the course of intervention. Independent t tests were used to compare the groups. Participants in both groups were asked the following open-ended question: "What did you think of the intervention?".

RESULTS

There were 52.9% participants in the detuned laser group and 53.8% participants in the manual therapy group who perceived that they had received the active intervention. The confidence ratings about their perceptions (6.7 ± 2.0, detuned laser group; 6.3 ± 2.4, manual therapy group) (P = .66) and the self-reported recovery ratings (1.9 ± 1.5 and 1.8 ± 1.2, respectively) (P = .77) were similar.

CONCLUSIONS

Participants in this study confidently perceived that detuned laser was an active intervention. They positively rated their recovery following the course of the placebo intervention and perceived that detuned laser was effective in treating their condition. Therefore, it is feasible for detuned laser to be used as a placebo for manual therapy trials.

A systematic review and meta-analysis of placebo effect in clinical trials on chronic prostatitis/chronic pelvic pain syndrome

BACKGROUND

It is a common practice to control efficacy of pharmacological treatment with a placebo group. However, placebo itself may affect subjective and even objective results. The purpose of this study was to evaluate the placebo effect on symptoms of CP/CPPS to improve future clinical trials.

METHODS

A search at three databases (Scopus, MEDLINE, and Web of Science) was conducted to identify double-blind placebo-controlled clinical trials on the treatment of CP/CPPS published until April 2021. The primary outcome - National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) score.

SECONDARY OUTCOMES

Qmax, PVR, IPSS, and prostate volume.

RESULTS

A total of 3502 studies were identified. Placebo arms of 42 articles (5512 patients, median 31 patients) were included in the systematic review. Systematic review identified positive changes in the primary endpoint, meta-analysis of 10 articles found that NIH-CPSI total score results were significantly influenced by placebo, mean difference -4.2 (95% confidence interval [CI]: -6.31, -2.09). Mean difference of NIH-CPSI pain domain was -2.31 (95% CI: -3.4, -1.21), urinary domain -1.12 (95% CI: -1.62, -0.62), quality of life domain -1.67 (95% CI: -2.38, -0.96); p < 0.001 for all. In case of the objective indicator - Qmax, there were three articles included in the meta-analysis. Qmax mean change from baseline was 0.68 (95% CI: -0.85, 2.22, p = 0.38). Systematic review showed no significant changes in pain, measured by VAS or other scores, IPSS and PVR.

CONCLUSIONS

Placebo significantly affected the subjective parameters (NIH-CPSI) and limitedly affected various other measurements of pain (visual analog scale, McGill pain questionnaire). There was no long-term effect on IPSS and objective measurements (Qmax, PVR). This study can be used in further clinical trials to develop general rules of CPPS treatment assessment.

Opicapone versus placebo in the treatment of Parkinson’s disease patients with end-of-dose motor fluctuation-associated pain: rationale and design of the randomised, double-blind OCEAN (OpiCapone Effect on motor fluctuations and pAiN) trial

Background

Optimisation of dopaminergic therapy may alleviate fluctuation-related pain in Parkinson’s disease (PD). Opicapone (OPC) is a third-generation, once-daily catechol-O-methyltransferase inhibitor shown to be generally well tolerated and efficacious in reducing OFF-time in two pivotal trials in patients with PD and end-of-dose motor fluctuations. The OpiCapone Effect on motor fluctuations and pAiN (OCEAN) trial aims to investigate the efficacy of OPC 50 mg in PD patients with end-of-dose motor fluctuations and associated pain, when administered as adjunctive therapy to existing treatment with levodopa/dopa decarboxylase inhibitor (DDCi).

Methods

OCEAN is a Phase IV, international, multicentre, randomised, double-blind, placebo-controlled, parallel-group, interventional trial in PD patients with end-of-dose motor fluctuations and associated pain. It consists of a 1-week screening period, 24-week double-blind treatment period and 2-week follow-up period. Eligible patients will be randomised 1:1 to OPC 50 mg or placebo once daily while continuing current treatment with levodopa/DDCi and other chronic, stable anti-PD and/or analgesic treatments. The primary efficacy endpoint is change from baseline in Domain 3 (fluctuation-related pain) of the King’s Parkinson’s disease Pain Scale (KPPS). The key secondary efficacy endpoint is change from baseline in Domain B (anxiety) of the Movement Disorder Society-sponsored Non-Motor rating Scale (MDS-NMS). Additional secondary efficacy assessments include other domains and total scores of the KPPS and MDS-NMS, the Parkinson’s Disease Questionnaire (PDQ-8), the MDS-sponsored Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Parts III and IV, Clinical and Patient’s Global Impressions of Change, and change in functional status via Hauser’s diary. Safety assessments include the incidence of treatment-emergent adverse events. The study will be conducted in approximately 140 patients from 50 clinical sites in Germany, Italy, Portugal, Spain and the United Kingdom. Recruitment started in February 2021 and the last patient is expected to complete the study by late 2022.

Discussion

The OCEAN trial will help determine whether the use of adjunctive OPC 50 mg treatment can improve fluctuation-associated pain in PD patients with end-of-dose motor fluctuations. The robust design of OCEAN will address the current lack of reliable evidence for dopaminergic-based therapy in the treatment of PD-associated pain.

Trial registration

EudraCT number 2020–001175-32; registered on 2020-08-07.

Experience with opioids does not modify the brain network involved in expectations of placebo analgesia

Placebo analgesia (PA) is defined as a psychobiological phenomenon triggered by the information surrounding an analgesic drug instead of its inherent pharmacological properties. PA is hypothesized to be formed through either verbal suggestions or conditioning. The present study aims at disentangling the neural correlates of expectations effects with or without conditioning through prior experience using the model of PA.

We addressed this question by recruiting two groups of individuals holding comparable verbally‐induced expectations regarding morphine analgesia but either (i) with or (ii) without prior experience with opioids. We then contrasted the two groups' neurocognitive response to acute heat‐pain induction following the injection of sham morphine using electroencephalography (EEG). Topographic ERP analyses of the N2 and P2 pain evoked potential components allowed to test the hypothesis that PA involves distinct neural networks when induced by expectations with or without prior experience.

First, we confirmed that the two groups showed corresponding expectations of morphine analgesia (Hedges' g_s < .4 positive control criteria, g_s = .37 observed difference), and that our intervention induced a medium‐sized PA (Hedges' g_av ≥ .5 positive control, g_av = .6 observed PA). We then tested our hypothesis on the recruitment of different PA‐associated brain networks in individuals with versus without prior experience with opioids and found no evidence for a topographic N2 and P2 ERP components difference between the two groups. Our results thus suggest that in the presence of verbally‐induced expectations, modifications in the PA‐associated brain activity by conditioning are either absent or very small.

Temporal expectancy induced by the mere possession of a placebo analgesic affects placebo analgesia: preliminary findings from a randomized controlled trial

Research on placebo analgesia usually shows that people experienced a reduction in pain after using a placebo analgesic. An emerging line of research argues that, under some circumstances, merely possessing (but not using) a placebo analgesic could induce placebo analgesia. The current study investigates how temporary expectation of pain reduction associated with different forms of possessing a placebo analgesic affects pain outcomes. Healthy participants (n = 90) were presented with a vial of olive oil (placebo), described as a blended essential oil that blocks pain sensations upon nasal inhalation, and were asked to anticipate the benefits of such analgesic oil to the self (such as anticipating the analgesic oil to reduce their pain). Participants were randomized into one of three different possession conditions: physical-possession condition (participants possessed a tangible placebo analgesic oil, inducing an expectation to acquire analgesic benefit early upon the experience of pain), psychological-possession condition (participants possessed a coupon, which can be redeemed for a placebo analgesic oil, inducing an expectation to acquire analgesic benefit later upon the experience of pain), or no-possession condition. Participants did a cold pressor test (CPT) to experience experimentally-induced pain on their non-dominant hand. Their objective physical pain responses (pain-threshold and pain-tolerance), and subjective psychological pain perception (pain intensity, severity, quality, and unpleasantness) were measured. Results revealed that participants in the physical-possession condition reported greater pain-threshold, F(2, 85) = 6.65, p = 0.002, and longer pain-tolerance, F(2, 85) = 7.19, p = 0.001 than participants in the psychological-possession and no-possession conditions. No significant group difference was found in subjective pain perception. The results of this study can advance knowledge about pain mechanisms and novel pain management.

Placebo and hypnosis in the clinical setting: Contextual factors in hypnotic analgesia

The assumption that hypnotic analgesia produces placebo effects is controversial. The cognitive dimension that can distinguish hypnosis from placebo analgesia has been suggested as hypnotic susceptibility. The aim of this study is to investigate the role of the relationship between patient and therapist, assumed to produce the placebo effect, in the clinical context of hypnotic treatment for pain. Seventy subjects were given hypnosis administered by the therapist in person (Group A) and 37 practiced self-hypnosis (Group B) for 8 weeks. The Somatosensory Amplification Scale (SSAS), Stanford hypnotic susceptibility scale type A, Cold pressor test (CPT) and SCL-90 were administered at baseline, and Italian Pain Questionnaire (IPQ) dimensions were used as outcome measures. The SSAS did appear to reflect the efficacy of hypnotic analgesia in all pain variables explored, but only in Group B. An improvement in pain intensity and all IPQ dimensions were found at 8 weeks. In particular, an improvement in the affective dimension of pain, with a medium-high effect size (η2 = .774), was recorded after hypnotic analgesia, with the outcome being better in Group A than in Group B (p = .001). This outcome was independent of hypnotic susceptibility in both groups. Considering our hypothesis that, given the administration of the same suggestions, the therapist could promote the placebo response, contributing to the improvement in the affective dimension of pain outcome, which exhibited a response to the hypnotic treatment independently of hypnotic susceptibility.

Benchmarking occupational exoskeletons: An evidence mapping systematic review

OBJECTIVES

To provide an overview of protocols assessing the effect of occupational exoskeletons on users and to formulate recommendations towards a literature-based assessment framework to benchmark the effect of occupational exoskeletons on the user.

METHODS

PubMed (MEDLINE), Web of Science database and Scopus were searched (March 2, 2021). Studies were included if they investigated the effect of one or more occupational exoskeletons on the user.

RESULTS

In total, 139 eligible studies were identified, encompassing 33, 25 and 18 unique back, shoulder and other exoskeletons, respectively. Device validation was most frequently conducted using controlled tasks while collecting muscle activity and biomechanical data. As the exoskeleton concept matures, tasks became more applied and the experimental design more representative. With that change towards realistic testing environments came a trade-off with experimental control, and user experience data became more valuable.

DISCUSSION

This evidence mapping systematic review reveals that the assessment of occupational exoskeletons is a dynamic process, and provides literature-based assessment recommendations. The homogeneity and repeatability of future exoskeleton assessment experiments will increase following these recommendations. The current review recognises the value of variability in evaluation protocols in order to obtain an overall overview of the effect of exoskeletons on the users, but the presented framework strives to facilitate benchmarking the effect of occupational exoskeletons on the users across this variety of assessment protocols.

The Placebo Response in Double-Blind Randomised Trials Evaluating Regenerative Therapies for Parkinson's Disease: A Systematic Review and Meta-Analysis

In the field of stem cell technologies, exciting advances are taking place leading to translational research to develop cell-based therapies which may replace dopamine releasing neurons lost in patients with Parkinson's disease (PD). A major influence on trial design has been the assumption that the use of sham operated comparator groups is required in the implementation of randomised double-blind trials to evaluate the placebo response and effects associated with the surgical implantation of cells. The aim of the present review is to identify the improvements in motor functioning and striatal dopamine release in patients with PD who have undergone sham surgery. Of the nine published trials, there was at the designated endpoints, a pooled average improvement of 4.3 units, with 95% confidence interval of 3.1 to 5.6 on the motor subscale of the Unified Parkinson's Disease Scale in the 'OFF' state. This effect size indicates a moderate degree of improvement in the motor functioning of the patients in the sham surgical arms of the trials. Four of the nine trials reported the results of 18F-Fluorodopa PET scans, indicating no improvements of dopaminergic nigrostriatal neurones following sham surgery. Therefore, while the initial randomised trials relying on the use of sham operated controls were justified on methodological grounds, we suggest that the analysis of the evidence generated by the completed and published trials indicates that placebo controlled trials are not necessary to advance and evaluate the safety and efficacy of emerging regenerative therapies for PD.

The placebo and nocebo effects in functional urology

A placebo is an inert substance normally used in clinical trials for comparison with an active substance. However, a placebo has been shown to have an effect on its own; commonly known as the placebo effect. A placebo is an essential component in the design of conclusive clinical trials but has itself become the focus of intense research. The placebo effect is partly the result of positive expectations of the recipient on the state of health. Conversely, a nocebo effect is when negative expectations from a substance lead to poor treatment outcomes and/or adverse events. Randomized controlled trials in functional urology have demonstrated the importance of the placebo and nocebo effects across different diseases such as overactive bladder, urinary incontinence, lower urinary tract symptoms and interstitial cystitis/painful bladder syndrome, as well as male and female sexual dysfunction. Understanding the true nature of the placebo-nocebo complex and the scope of its effect in functional urology could help urologists to maximize the positive effects of this phenomenon while minimizing its potentially negative effects.

Do manual therapies have a specific autonomic effect? An overview of systematic reviews

Background

The impact of manual therapy interventions on the autonomic nervous system have been largely assessed, but with heterogeneous findings regarding the direction of these effects. We conducted an overview of systematic reviews to describe if there is a specific autonomic effect elicited by manual therapy interventions, its relation with the type of technique used and the body region where the intervention was applied.

Methods

We conducted an overview according to a publicly registered protocol. We searched the Cochrane Database of Systematic Reviews, MEDLINE, EPISTEMONIKOS and SCOPUS, from their inception to march 2021. We included systematic reviews for which the primary aim of the intervention was to assess the autonomic effect elicited by a manual therapy intervention in either healthy or symptomatic individuals. Two authors independently applied the selection criteria, assessed risk of bias from the included reviews and extracted data. An established model of generalisation guided the data analysis and interpretation.

Results

We included 12 reviews (5 rated as low risk of bias according the ROBIS tool). The findings showed that manual therapies may have an effect on both sympathetic and parasympathetic systems. However, the results from included reviews were inconsistent due to differences in their methodological rigour and how the effects were measured. The reviews with a lower risk of bias could not discriminate the effects depending on the body region to which the technique was applied.

Conclusion

The magnitude of the specific autonomic effect elicited by manual therapies and its clinical relevance is uncertain. We point out some specific recommendations in order to improve the quality and relevance of future research in this field.

Real Bodies Not Required? Placebo Analgesia and Pain Perception in Immersive Virtual and Augmented Reality

Pain represents an embodied experience, wherein inferences are not only drawn from external sensory inputs, but also from bodily states. Previous research has demonstrated that a placebo administered to an embodied rubber hand can effectively induce analgesia, providing first evidence that placebos can work even when applied to temporarily embodied, artificial body parts. Using a heat pain paradigm, the present study investigates placebo analgesia and pain perception during virtual embodiment. We examined whether a virtual placebo (a sham heat protective glove) can successfully induce analgesia, even when administered to a virtual body. The analgesic efficacy of the virtual placebo to the real hand (augmented reality setting) or virtual hand (virtual reality setting) was compared to a physical placebo administered to the own, physical body (physical reality setting). Furthermore, pain perception and subjective embodiment were compared between settings. In this mixed design experiment, healthy participants (n=48) were assigned to either an analgesia-expectation or control-expectation group, where subjective and objective pain was measured at pre- and post-intervention time points. Results demonstrated that pre-intervention pain intensity was lower in the virtual reality setting, and that participants in the analgesia-expectation condition, after the intervention, exhibited significantly higher pain thresholds, and lower pain intensity and unpleasantness ratings than control-expectation participants, independent of the setting. Our findings show that a virtual placebo can elicit placebo analgesia comparable to that of a physical placebo, and that administration of a placebo does not necessitate physical bodily interaction to produce analgesic responses.

Effectiveness of self-help plus (SH+) in reducing anxiety and post-traumatic symptomatology among care home workers during the COVID-19 pandemic: a randomized controlled trial

This article describes a randomized controlled trial to evaluate the effectiveness of a supervised online delivery of self-help plus (SH+), during the second wave of COVID-19 contagions in Northern Italy. The SH+ is a psychological intervention developed by the World Health Organization to increase a person's ability to deal with stress. In this trial, it was tested primarily as a tool to reduce anxiety and post-traumatic symptomatology in workers of residential nursing and care homes. In order to partial out non-specific effects of the intervention, the SH+ was compared to an equally supervised and structured alternative activity. Secondarily, in view of future emergencies, the potential of SH+ as a tool to reduce perceived stress, increase subjective well-being and foster individual resilience was explored. At post-intervention, the preregistered analysis revealed no difference in self-reported anxiety and/or post-traumatic symptomatology between the group receiving the SH+ and the group engaged in an alternative activity. Some specific and positive effects of the SH+ intervention were only found on self-reported intervention effectiveness and engagement in exploratory analyses. These findings raise the question whether the previously documented effectiveness of the SH+ on self-reported symptomatology and on the prevention of psychiatric conditions could be attributed mostly to non-specific rather than specific factors connected with participant enrolment in a psychological intervention. Indeed, the effects of the SH+ had been previously compared only to the effects of not being engaged in any alternative activity (often described in the literature as 'treatment as usual'-or 'enhanced treatment as usual', when some relevant information is given to the control group as a one-off). Given the negative findings of this study, before the SH+ is implemented in clinical practice, further studies should be conducted to examine its short- and long-term beneficial effects, by means of randomized studies that employ alternative but similarly structured interventions as control conditions, aiming to minimize the confounding effect of non-specific factors.

Differential power of placebo across major psychiatric disorders: a preliminary meta-analysis and machine learning study

The placebo effect across psychiatric disorders is still not well understood. In the present study, we conducted meta-analyses including meta-regression, and machine learning analyses to investigate whether the power of placebo effect depends on the types of psychiatric disorders. We included 108 clinical trials (32,035 participants) investigating pharmacological intervention effects on major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SCZ). We developed measures based on clinical rating scales and Clinical Global Impression scores to compare placebo effects across these disorders. We performed meta-analysis including meta-regression using sample-size weighted bootstrapping techniques, and machine learning analysis to identify the disorder type included in a trial based on the placebo response. Consistently through multiple measures and analyses, we found differential placebo effects across the three disorders, and found lower placebo effect in SCZ compared to mood disorders. The differential placebo effects could also distinguish the condition involved in each trial between SCZ and mood disorders with machine learning. Our study indicates differential placebo effect across MDD, BD, and SCZ, which is important for future neurobiological studies of placebo effects across psychiatric disorders and may lead to potential therapeutic applications of placebo on disorders more responsive to placebo compared to other conditions.

[The effect of treatment expectations on pruritus and skin pain]

Hintergrund

Patientenerwartungen in Bezug auf den Nutzen einer medizinischen Behandlung stellen eine wichtige Determinante für die Placeboantwort dar. Sie können Entwicklung und Verlauf von Erkrankungen sowie Wirksamkeit und Verträglichkeit von Therapien maßgeblich beeinflussen. Die Mechanismen, die diese Placebo- und Noceboeffekte vermitteln, wurden bislang am besten auf dem Gebiet der Placeboanalgesie beschrieben. Aber auch in der Dermatologie findet sich eine zunehmende Evidenz dafür, dass verschiedene Symptome wie Schmerzen an der Haut und Pruritus (Jucken) sowie verschiedene dermatologische Erkrankungen durch die Behandlungserwartungen von Patienten moduliert werden können.

Ziel der Arbeit

Das Ziel dieser Arbeit ist die Darstellung der aktuellen Datenlage in Bezug auf den Einfluss von Erwartungseffekten auf dermatologische Symptome wie Pruritus und Hautschmerzen sowie auf verschiedene dermatologische Erkrankungen. Schließlich soll die Bedeutung dieses Themas für Ärzte, die Patienten mit Hautsymptomen behandeln, vermittelt werden.

Material und Methoden

Es handelt sich um eine narrative Übersichtsarbeit.

Ergebnisse und Diskussion

Eine zunehmende Anzahl von Studien an gesunden Probanden und dermatologischen Patienten zeigt, dass Hautsymptome wie Pruritus und Schmerzen durch die Induktion positiver Erwartungen verringert und durch die Induktion negativer Erwartungen verstärkt werden können. Vorherige Behandlungserfahrungen der Patienten sowie die Qualität und Quantität der Arzt-Patienten-Kommunikation spielen für die Induktion der Behandlungserwartung eine zentrale Rolle.

Schlussfolgerung

Techniken, die darauf abzielen, positive Erwartungseffekte von Patienten mit Hautsymptomen zu maximieren und negative zu minimieren, sollten in die klinische Routine implementiert werden.

Sham-derived effects and the minimal reliability of theta burst stimulation

Theta-burst stimulation (TBS) is a patterned form of repetitive transcranial magnetic stimulation (rTMS) that has been used to induce long-term modulation (plasticity) of corticospinal excitability in a drastically shorter duration protocol than conventional rTMS protocols. In this study we tested the reliability of the effects of two well defined TBS protocols, continuous TBS (cTBS) and intermittent TBS (iTBS), especially in relation to sham TBS, within and across the same 24 participants. All TBS protocols were repeated after approximately 1 month to assess the magnitude and reliability of the modulatory effects of each TBS protocol. Baseline and post-TBS changes in motor evoked potentials (MEP—measure of corticospinal excitability) amplitudes were compared across the cTBS, iTBS and sham TBS protocols and between the initial and retest visits. Overall, across participants, at the initial visit, iTBS facilitated MEPs as compared to baseline excitability, with sham eliciting the same effect. cTBS did not show a significant suppression of excitability compared to baseline MEPs at either visit, and even facilitated MEPs above baseline excitability at a single time point during the repeat visit. Otherwise, effects of TBS were generally diminished in the repeat visit, with iTBS and sham TBS replicating facilitation of MEPs above baseline excitability at similar time points. However, no protocol demonstrated consistent intra-individual modulation of corticospinal excitability upon retest. As the first study to test both iTBS and cTBS against sham TBS across repeat visits, our findings challenge the efficacy and reliability of TBS protocols and emphasize the importance of accounting for sham effects of TBS. Furthermore, given that therapeutic effects of TBS are hypothetically derived from consistent and repeated modulation of brain activity, the non-replicability of plasticity and sham effects call into question these basic mechanisms.

Expectation-induced enhancement of pain, itch and quality of life in psoriasis patients: study protocol of a randomised controlled trial

INTRODUCTION

Experimental and clinical data demonstrate that skin diseases like psoriasis are affected by psychological factors and can be modulated by interventions other than conventional drug therapy. The expectation of patients towards the benefit of a forthcoming treatment as well as treatment pre-experiences have been demonstrated as crucial factors mediating placebo responses in inflammatory skin diseases. However, it is unknown whether and to what extent treatment outcomes of psoriasis patients under therapy with monoclonal antibodies like secukinumab can be experimentally modulated at subjective and physiological levels by modifying the expectation of patients via verbal instruction or prior experience.

METHODS AND ANALYSIS

Treatment expectations will be modulated in patients with moderate-to-severe psoriasis undergoing treatment with the anti-interleukin-17A monoclonal antibody secukinumab. Patients with a Psoriasis Area and Severity Index (PASI) >12 will be randomly allocated to one of three groups (N=40 each). As a standard schedule, patients in the pharmacological control group (group 1) will be treated weekly with 300 mg secukinumab, while patients in groups 2 and 3 will receive only 75 mg secukinumab (75% dose reduction) during all treatment weeks. In addition to the injections, patients in group 3 will ingest a novel tasting drink, with a cover story explaining that previous studies showed additional beneficial effects of this combination (drug and drink). Patients will be assessed and treated at nine visits over a 16-week period, during which the severity of pain and itch symptoms, skin lesions and quality of life will be analysed with standardised questionnaires and the PASI.

ETHICS AND DISSEMINATION

This study was approved by the Ethics committee of the Medical Faculty of the University Duisburg-Essen. Study outcomes will be published in peer-reviewed scientific journals.

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.

Blinding and expectancy confounds in psychedelic randomized controlled trials

Introduction: There is increasing interest in the potential for psychedelic drugs such as psilocybin, LSD and ketamine to treat several mental health disorders, with a growing number of randomized controlled trials (RCTs) being conducted to investigate the therapeutic effectiveness of psychedelics.Areas covered: We review previous literature on expectancy effects and blinding in the context of psychedelic RCTs - literature which strongly suggest that psychedelic RCTs might be confounded by de-blinding and expectancy. We conduct systematic reviews of psychedelic RCTs using Medline, PsychInfo and EMBASE (Jan 1990 - Nov 2020) and show that currently reported psychedelic RCTs have generally not reported pre-trial expectancy, nor the success of blinding procedures.Expert opinion: While psychedelic RCTs have generally shown promising results, with large effect sizes reported, we argue that treatment effect sizes in psychedelic RCTs are likely over-estimated due to de-blinding of participants and high levels of response expectancy. We suggest that psychedelic RCTs should routinely measure de-blinding and expectancy. Careful attention should be paid to clinical trial design and the instructions given to participants to allow these confounds to be reduced, estimated and removed from effect size estimates. We urge caution in interpreting effect size estimates from extant psychedelic RCTs.

Placebos and Movies: What Do They Have in Common?

Placebos are fake therapies that can induce real therapeutic effects, called placebo effects. It goes without saying that what matters for inducing a placebo effect is not so much the fake treatment itself, but rather the therapeutic ritual that is carried out, which is capable of triggering psychobiological mechanisms in the patient’s brain. Both laypersons and scientists often accept the phenomenon of the placebo effect with reluctance, as fiction-induced clinical improvements are at odds with common sense. However, it should be emphasized that placebo effects are not surprising after all if one considers that fiction-induced physiological effects occur in everyday life. Movies provide one of the best examples of how fictitious reality can induce psychological and physiological responses, such as fear, love, and tears. In the same way that a horror movie induces fear-related physiological responses, even though the viewer knows everything is fake, so the sight of a syringe may trigger the release of pain-relieving chemicals in the patient’s brain, even if the patient knows there is a fake painkiller inside. From this perspective, placebos can be better conceptualized as rituals, actions, and fictions within a more general framework that emphasizes the power of psychological factors in everyday life, including the healing context.

Digital Technology in Clinical Trials for Multiple Sclerosis: Systematic Review

Clinical trials in multiple sclerosis (MS) have been including digital technology tools to overcome limitations in treatment delivery and disease monitoring. In March 2020, we conducted a systematic search on pubmed.gov and clinicaltrials.gov databases (with no restrictions) to identify all relevant published and unpublished clinical trials, in English language, including MS patients, in which digital technology was applied. We used “multiple sclerosis” and “clinical trial” as the main search words, and “app”, “digital”, “electronic”, “internet” and “mobile” as additional search words, separately. Digital technology is part of clinical trial interventions to deliver psychotherapy and motor rehabilitation, with exergames, e-training, and robot-assisted exercises. Digital technology has been used to standardise previously existing outcome measures, with automatic acquisitions, reduced inconsistencies, and improved detection of symptoms (e.g., electronic recording of motor performance). Other clinical trials have been using digital technology for monitoring symptoms that would be otherwise difficult to detect (e.g., fatigue, balance), for measuring treatment adherence and side effects, and for self-assessment purposes. Collection of outcome measures is progressively shifting from paper-based on site, to internet-based on site, and, in the future, to internet-based at home, with the detection of clinical and treatment features that would have remained otherwise invisible. Similarly, remote interventions provide new possibilities of motor and cognitive rehabilitation.