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

Behaviorally conditioned effects of psychoactive drugs in experimental animals: What we have learned from nearly a century of research and what remains to be learned

Continuous treatment with drugs is a crucial requirement for managing various clinical conditions, including chronic pain and neuropsychiatric disorders such as depression or schizophrenia. Associative learning processes, i.e. Pavlovian conditioning, can play an important role for the effects of drugs and could open new avenues for optimizing patient treatment. In this narrative literature review, we summarize available data in experimental animals regarding the behaviorally conditioned effects of psychostimulants such as d-amphetamine and cocaine, the dopamine receptor agonist apomorphine, the dopamine receptor antagonist haloperidol, morphine and antidepressant drugs. In each section, the drug under discussion is briefly introduced, followed by a detailed examination of conditioning features, including doses and dosing regimens, characteristics of the conditioning process such as test environments or specific conditioned stimuli, testing and conditioned response characteristics, possible extinction or reconditioning or reversal training, neural mechanisms, and finally, the potential clinical relevance of the research area related to the drug. We focus on key outcomes, delve into methodical issues, identify gaps in current knowledge, and suggest future research directions.

Expectation of pain and relief: A dynamical model of the neural basis for pain-trauma co-morbidity

Posttraumatic Stress Disorder (PTSD) is highly co-morbid with chronic pain conditions. When present, PTSD significantly worsens chronic pain outcomes. Likewise, pain contributes to a more severe PTSD as evidenced by greater disability, more frequent use of harmful opioid analgesics and increased pain severity. The biomechanism behind this comorbidity is incompletely understood, however recent work strongly supports the widely-accepted role of expectation, in the entanglement of chronic pain and trauma symptoms. This work has shown that those with trauma have a maladaptive brain response while expecting stress and pain, whereas those with chronic pain may have a notable impairment in brain response while expecting pain relief. This dynamical expectation model of the interaction between neural systems underlying expectation of pain onset (traumatic stress) and pain offset (chronic pain) is biologically viable and may provide a biomechanistic insight into pain-trauma comorbidity. These predictive mechanisms work through interoceptive pathways in the brain critically the insula cortex. Here we highlight how the neural expectation-related mechanisms augment the existing models of pain and trauma to better understand the dynamics of pain and trauma comorbidity. These ideas will point to targeted complementary clinical approaches, based on mechanistically separable neural biophenotypes for the entanglement of chronic pain and trauma symptoms.

Assessing expectancy and suggestibility in a trial of escitalopram v. psilocybin for depression

BACKGROUND

To investigate the association between pre-trial expectancy, suggestibility, and response to treatment in a trial of escitalopram and investigational drug, COMP360, psilocybin, in the treatment of major depressive disorder (ClinicalTrials.gov registration: NCT03429075).

METHODS

We used data (n = 55) from our recent double-blind, parallel-group, randomized head-to-head comparison trial of escitalopram and investigational drug, COMP360, psilocybin. Mixed linear models were used to investigate the association between pre-treatment efficacy-related expectations, as well as baseline trait suggestibility and absorption, and therapeutic response to both escitalopram and COMP360 psilocybin.

RESULTS

Patients had significantly higher expectancy for psilocybin relative to escitalopram; however, expectancy for escitalopram was associated with improved therapeutic outcomes to escitalopram, expectancy for psilocybin was not predictive of response to psilocybin. Separately, we found that pre-treatment trait suggestibility was associated with therapeutic response in the psilocybin arm, but not in the escitalopram arm.

CONCLUSIONS

Overall, our results suggest that psychedelic therapy may be less vulnerable to expectancy biases than previously suspected. The relationship between baseline trait suggestibility and response to psilocybin therapy implies that highly suggestible individuals may be primed for response to this treatment.

Patient Expectations and Therapeutic Alliance Affect Pain Reduction Following Lidocaine Infusion in an Interdisciplinary Chronic Pain Clinic

Pain experience is affected by both ascending nociceptive signals and descending modulation. Expectations can affect pain experience and augment treatment-induced analgesia through descending inhibitory modulation of pain. This open-label, prospective cohort study examined the association between participant expectation ratings and pain reduction in adult participants with chronic pain receiving an intravenous lidocaine infusion. We aimed to explore whether: 1) participants' expectations of treatment efficacy were associated with pain reduction over 8 weeks after infusion; and 2) participants' therapeutic alliance was associated with expectations and/or pain reduction. We recruited 70 participants with chronic pain scheduled for lidocaine infusion. Study measures included pain intensity (pre-treatment, post-treatment, and daily for 8 weeks), treatment expectations (EXPECT), and therapeutic alliance (Trust in Physician and Working Alliance Inventory-Short Revised). Baseline treatment expectations were significantly correlated with pain reduction (r = .42, P < .01). Therapeutic alliance was significantly correlated with expectations (r = .27, P < .05) and pain reduction (r = .38, P < .01). This study quantifies the contribution of: 1) treatment expectations; and 2) therapeutic alliance to the magnitude of lidocaine-induced pain reduction. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes. PERSPECTIVE: This study evaluates the relationship between pain reduction and ratings of: 1) treatment expectations; and 2) therapeutic alliance following an intravenous lidocaine infusion. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes.

Neuroimaging of opioid effects in humans across conditions of acute administration, chronic pain therapy, and opioid use disorder

Evidence of central nervous system (CNS) exogenous opioid effects in humans has been primarily gained through neuroimaging of three participant populations: individuals after acute opioid administration, those with opioid use disorder (OUD), and those with chronic pain receiving opioid therapy. In both the brain and spinal cord, opioids alter processes of pain, cognition, and reward. Opioid-related CNS effects may persist and accumulate with longer opioid use duration. Meanwhile, opioid-induced benefits versus risks to brain health remain unclear. This review article highlights recent accumulating evidence for how exogenous opioids impact the CNS in humans. While investigation of CNS opioid effects has remained largely disparate across contexts of opioid acute administration, OUD, and chronic pain opioid therapy, integration across these contexts may enable advancement toward effective interventions.

Reframing pain: the power of individual and societal factors to enhance pain treatment

The effectiveness of analgesics can be increased if synergistic behavioural, psychological, and pharmacological interventions are provided within a supportive environment.

Working with patients' treatment expectations - what we can learn from homeopathy

The usual homeopathic remedy, "globules," does not contain any pharmacologically active ingredient. However, many patients and practitioners report beneficial effects of homeopathic treatment on various health outcomes. Experimental and clinical research of the last two decades analyzing the underlying mechanisms of the placebo effect could explain this phenomenon, with patients' treatment expectations as the predominant mechanism. Treatment expectations can be optimized through various factors, such as prior information, communication, and treatment context. This narrative review analyses how homeopathy successfully utilizes these factors. Subsequently, it is discussed what evidence-based medicine could learn from homeopathic practice to optimize treatment expectations (e.g., using an empathic, patient-centered communication style, deliberately selecting objects in practice rooms, or using clear treatment rituals and salient contextual stimuli) and thereby treatment effectiveness. Homeopathic remedy does not work beyond the placebo effect but is recommended or prescribed as an active treatment by those who believe in it. Thus, practitioners need to understand the manner in which homeopathy (as an example of inert treatment) works and are advised to reintegrate its underlying effective placebo mechanisms into evidence-based medicine. This promises to increase treatment efficacy, tolerability, satisfaction, and compliance with evidence-based treatments, and addresses the desires patients are trying to satisfy in homeopathy in an ethical, fully informed way that is grounded in evidence-based medicine.

The downside to choice: instrumental control increases conditioned nocebo hyperalgesia

ABSTRACT

Nocebo hyperalgesia is a pervasive problem in which the treatment context triggers negative expectations that exacerbate pain. Thus, developing ethical strategies to mitigate nocebo hyperalgesia is crucial. Emerging research suggests that choice has the capacity to reduce nocebo side effects, but choice effects on nocebo hyperalgesia have not been explored. This study investigated the impact of choice on conditioned nocebo hyperalgesia using a well-established electrocutaneous pain paradigm where increases in noxious stimulation were surreptitiously paired with the activation of a sham device. In study 1, healthy volunteers (N = 104) were randomised to choice over (nocebo) treatment administration, nocebo administration without choice, or a natural history control group. Nocebo hyperalgesia was greater for those with choice than no choice, suggesting that choice increased rather than diminished nocebo hyperalgesia. Study 2 tested whether providing positive information about the benefits of choice in coping with pain could counteract heightened nocebo hyperalgesia caused by choice. A different sample of healthy adults (N = 137) were randomised to receive nocebo treatment with choice and positive choice information, choice only, or no choice. The positive choice information failed to attenuate the effect of choice on nocebo hyperalgesia. The current results suggest that, rather than decreasing nocebo hyperalgesia, treatment choice may exacerbate pain outcomes when a painful procedure is repeatedly administered. As such, using choice as a strategy to mitigate nocebo outcomes should be treated with caution.

Expectancy Effects in Psychedelic Trials

Clinical trials of psychedelic compounds like psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltrptamine (DMT) have forced a reconsideration of how nondrug factors, such as participant expectations, are measured and controlled in mental health research. As doses of these profoundly psychoactive substances increase, so does the difficulty in concealing the treatment condition in the classic double-blind, placebo-controlled trial design. As widespread public enthusiasm for the promise of psychedelic therapy grows, so do questions regarding whether and how much trial results are biased by positive expectancy. First, we review the key concepts related to expectancy and its measurement. Then, we review expectancy effects that have been reported in both micro- and macrodose psychedelic trials from the modern era. Finally, we consider expectancy as a discrete physiological process that can be independent of, or even interact with, the drug effect. Expectancy effects can be harnessed to improve treatment outcomes and can also be actively managed in controlled studies to enhance the rigor and generalizability of future psychedelic trials.

Learning by observing: a systematic exploration of modulatory factors and the impact of observationally induced placebo and nocebo effects on treatment outcomes

Introduction

Observational learning (OL) refers to learning through observing other people's behavior. OL has been suggested as an effective and simple tool to evoke treatment expectations and corresponding placebo and nocebo effects. However, the exact mechanisms by which OL shapes treatment outcomes, its moderating factors and possible areas of application remain unclear. We thus reviewed the existing literature with two different literature searches to answer the following questions: Which influencing factors contribute to OL-induced placebo and nocebo effects (in healthy volunteers and patients) and how large are these effects (search 1)? In which medical fields has OL been used so far to modulate treatment expectancy and treatment outcomes in patients, their caregivers, and at-risk groups (search 2)? We also aimed to explore whether and how the assessment of treatment expectations has been incorporated.

Methods

We conducted two independent and comprehensive systematic literature searches, both carried out on September 20, 2022.

Results

We identified 21 studies that investigated OL-mediated placebo and nocebo effects for pain and itch, the (placebo) efficacy of sham treatment on anxiety, and the (nocebo) induction of medication side effects (search 1). Studies showed that OL can efficiently induce placebo and nocebo effects across different presentation modes, with medium effect sizes on average: placebo effects, d = 0.79 (range: d = -0.36-1.58), nocebo effects, d = 0.61 (range: d = 0.04-1.5). Although several moderating factors have been investigated, their contribution to OL-induced effects remains unclear because of inconsistent results. Treatment expectation was assessed in only four studies. Regarding medical applications of OL (search 2), we found 12 studies. They showed that OL was effectively applied in preventive, therapeutic and rehabilitative interventions and that it was mainly used in the field of psychosomatics.

Discussion

OL effects on treatment outcomes can be both positive and negative. Future research should investigate which individuals would benefit most from OL and how OL can be implemented most effectively to induce placebo and avoid nocebo effects in clinical settings.

Systematic review registration

This work was preregistered at the Center for Open Science as open-ended registration (doi: 10.17605/OSF.IO/FVHKE). The protocol can be found here: https://archive.org/details/osf-registrations-fvhke-v1.

The radiologist as a physician - artificial intelligence as a way to overcome tension between the patient, technology, and referring physicians - a narrative review

BACKGROUND

 Large volumes of data increasing over time lead to a shortage of radiologists' time. The use of systems based on artificial intelligence (AI) offers opportunities to relieve the burden on radiologists. The AI systems are usually optimized for a radiological area. Radiologists must understand the basic features of its technical function in order to be able to assess the weaknesses and possible errors of the system and use the strengths of the system. This "explainability" creates trust in an AI system and shows its limits.

METHOD

 Based on an expanded Medline search for the key words "radiology, artificial intelligence, referring physician interaction, patient interaction, job satisfaction, communication of findings, expectations", subjective additional relevant articles were considered for this narrative review.

RESULTS

 The use of AI is well advanced, especially in radiology. The programmer should provide the radiologist with clear explanations as to how the system works. All systems on the market have strengths and weaknesses. Some of the optimizations are unintentionally specific, as they are often adapted too precisely to a certain environment that often does not exist in practice - this is known as "overfitting". It should also be noted that there are specific weak points in the systems, so-called "adversarial examples", which lead to fatal misdiagnoses by the AI even though these cannot be visually distinguished from an unremarkable finding by the radiologist. The user must know which diseases the system is trained for, which organ systems are recognized and taken into account by the AI, and, accordingly, which are not properly assessed. This means that the user can and must critically review the results and adjust the findings if necessary. Correctly applied AI can result in a time savings for the radiologist. If he knows how the system works, he only has to spend a short amount of time checking the results. The time saved can be used for communication with patients and referring physicians and thus contribute to higher job satisfaction.

CONCLUSION

 Radiology is a constantly evolving specialty with enormous responsibility, as radiologists often make the diagnosis to be treated. AI-supported systems should be used consistently to provide relief and support. Radiologists need to know the strengths, weaknesses, and areas of application of these AI systems in order to save time. The time gained can be used for communication with patients and referring physicians.

KEY POINTS

  · Explainable AI systems help to improve workflow and to save time.. · The physician must critically review AI results, under consideration of the limitations of the AI.. · The AI system will only provide useful results if it has been adapted to the data type and data origin.. · The communicating radiologist interested in the patient is important for the visibility of the discipline..

CITATION FORMAT

· Stueckle CA, Haage P. The radiologist as a physician - artificial intelligence as a way to overcome tension between the patient, technology, and referring physicians - a narrative review. Fortschr Röntgenstr 2024; DOI: 10.1055/a-2271-0799.

Treatment guesses in the Treatment for Adolescents with Depression Study: Accuracy, unblinding and influence on outcomes

OBJECTIVE

We evaluated the presence and impact of unblinding during the influential Treatment for Adolescents with Depression Study (ClinicalTrials.gov Identifier: NCT00006286).

METHOD

Our analysis was part of a Restoring Invisible and Abandoned Trials reanalysis. Treatment for Adolescents with Depression Study trialled fluoxetine, placebo, cognitive behaviour therapy or their combination, in treating adolescents with major depressive disorder. We analysed the accuracy of guesses of fluoxetine or placebo allocation, and their effects on change in Children's Depression Rating Scale-Revised at 12 weeks.

RESULTS

Of 221 participants allocated to fluoxetine or placebo, 151 adolescents (68%) had their guess about pill-treatment-arm allocation recorded at week 6, and guesses were recorded for 154 independent evaluators, 159 parents and 164 pharmacotherapists. All of these groups guessed treatment allocation more accurately than would be expected by chance (60-66% accuracy; all p-values ⩽ 0.004). Guesses did not become more accurate between 6 and 12 weeks and were not predicted by adverse events, though event documentation was poor. Treatment guess had a substantial and statistically significant effect on outcome (Children's Depression Rating Scale-Revised change mean difference 9.12 [4.69; 13.55], β = 0.334, p < 0.001), but actual treatment arm did not (1.53 [-2.83; 5.89], β = 0.056, p = 0.489). Removing guess from the analysis increased the apparent effect of treatment arm, making it almost statistically significant at the conventional alpha-level of 0.05 (p = 0.06).

CONCLUSIONS

For Treatment for Adolescents with Depression Study, treatment guesses strongly predicted outcomes and may have led to the exaggeration of drug effectiveness in the absence of actual effects. The integrity of double-blinding in trials should be routinely assessed and reported.

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.

Paradigms matter: why persistent pain is different and how dentists can help

Dental professionals often expect, and are used to treating, pain that has a clear, organic and likely pathological cause. Patients visiting the dentist are also likely to share this expectation. However, in addition to potential organic contributions to the experience of pain, the nociceptive system (pain signalling system) also plays an important role. Alongside organic contributions, it is important to also consider that persistent pain is different to acute pain and requires different explanations and different management. Dental professionals need to be equipped to understand and explain persistent pain and to incorporate this understanding into their ongoing patient management so that patients can be educated in why the two are different and therefore require different approaches.

Negative expectations (nocebo phenomenon) in clinical interventions: A scoping review

Unpredictable, undesirable, and confusing reactions in the face of psychological or medical interventions make the clinical presentation more complicated and may represent clinically unexplained symptoms and also disturbed the doctor-patients relationship and decrease patients' benefits of treatment. It seems that negative expectations from the treatment (nocebo phenomenon) can explain such reactions. The aim of the current study is a scoping review and investigate different aspects of the nocebo phenomenon (negative expectations) in clinical interventions. This paper follows a scoping review of the existence, importance, and multidimensions of the nocebo phenomenon in medical and psychological interventions. Data sources include literature databases (ProQuest, PubMed, Google Scholar, and Scopus) reviewed from inception dates to 2023, and the terms negative expectations, nocebo effect, placebo effect, negative placebo, and clinical interventions were searched. The review of the available articles showed that negative expectations play an important role in the process and effectiveness of clinical interventions. Negative expectations (here named nocebo effect) can significantly interfere with rapport and treatment processes. Some underlying components of the nocebo effect include negative expectancies, conditioning, social learning, memory, cognitive distortions, meaning, motivation, somatic focus, negative reinforcements, personality, anxiety, and neurophysiological factors such as CCK, dopamine, and cortisol are proposed for development and presence of nocebo phenomenon in clinical practice. Negative expectations with its biopsychosocial aspects play an important and amazing role in disorganizing medical and psychological interventions. Using appropriate methods to reduce nocebo effects in therapeutic interventions may increase treatment compliance and adherence and increase the effectiveness of interventions.

When does the placebo effect have an impact on network meta-analysis results?

The placebo effect is the 'effect of the simulation of treatment that occurs due to a participant's belief or expectation that a treatment is effective'. Although the effect might be of little importance for some conditions, it can have a great role in others, mostly when the evaluated symptoms are subjective. Several characteristics that include informed consent, number of arms in a study, the occurrence of adverse events and quality of blinding may influence response to placebo and possibly bias the results of randomised controlled trials. Such a bias is inherited in systematic reviews of evidence and their quantitative components, pairwise meta-analysis (when two treatments are compared) and network meta-analysis (when more than two treatments are compared). In this paper, we aim to provide red flags as to when a placebo effect is likely to bias pairwise and network meta-analysis treatment effects. The classic paradigm has been that placebo-controlled randomised trials are focused on estimating the treatment effect. However, the magnitude of placebo effect itself may also in some instances be of interest and has also lately received attention. We use component network meta-analysis to estimate placebo effects. We apply these methods to a published network meta-analysis, examining the relative effectiveness of four psychotherapies and four control treatments for depression in 123 studies.

Identification of group differences in predictive anticipatory biasing of pain during uncertainty: preparing for the worst but hoping for the best

ABSTRACT

Pain anticipation during conditions of uncertainty can unveil intrinsic biases, and understanding these biases can guide pain treatment interventions. This study used machine learning and functional magnetic resonance imaging to predict anticipatory responses in a pain anticipation experiment. One hundred forty-seven participants that included healthy controls (n = 57) and individuals with current and/or past mental health diagnosis (n = 90) received cues indicating upcoming pain stimuli: 2 cues predicted high and low temperatures, while a third cue introduced uncertainty. Accurate differentiation of neural patterns associated with specific anticipatory conditions was observed, involving activation in the anterior short gyrus of the insula and the nucleus accumbens. Three distinct response profiles emerged: subjects with a negative bias towards high pain anticipation, those with a positive bias towards low pain anticipation, and individuals whose predictions during uncertainty were unbiased. These profiles remained stable over one year, were consistent across diagnosed psychopathologies, and correlated with cognitive coping styles and underlying insula anatomy. The findings suggest that individualized and stable pain anticipation occurs in uncertain conditions.

Systematic review and co-ordinate based meta-analysis to summarize the utilization of functional brain imaging in conjunction with human models of peripheral and central sensitization

BACKGROUND AND OBJECTIVE

Functional magnetic resonance imaging, in conjunction with models of peripheral and/or central sensitization, has been used to assess analgesic efficacy in healthy humans. This review aims to summarize the use of these techniques to characterize brain mechanisms of hyperalgesia/allodynia and to evaluate the efficacy of analgesics.

DATABASES AND DATA TREATMENT

Searches were performed (PubMed-Medline, Cochrane, Web of Science and Clinicaltrials.gov) to identify and review studies. A co-ordinate based meta-analysis (CBMA) was conducted to quantify neural activity that was reported across multiple independent studies in the hyperalgesic condition compared to control, using GingerALE software.

RESULTS

Of 217 publications, 30 studies met the inclusion criteria. They studied nine different models of hyperalgesia/allodynia assessed in the primary (14) or secondary hyperalgesia zone (16). Twenty-three studies focused on neural correlates of hyperalgesic conditions and showed consistent changes in the somatosensory cortex, prefrontal cortices, insular cortex, anterior cingulate cortex, thalamus and brainstem. The CBMA on 12 studies that reported activation coordinates for a contrast comparing the hyperalgesic state to control produced six activation clusters (significant at false discovery rate of 0.05) with more peaks for secondary (17.7) than primary zones (7.3). Seven studies showed modulation of brain activity by analgesics in five of the clusters but also in four additional regions.

CONCLUSIONS

This meta-analysis revealed substantial but incomplete overlap between brain areas related to neural mechanisms of hyperalgesia and those reflecting the efficacy of analgesic drugs. Studies testing in the secondary zone were more sensitive to evaluate analgesic efficacy on central sensitization at brainstem or thalamocortical levels.

SIGNIFICANCE

Experimental pain models that provide a surrogate for features of pathological pain conditions in healthy humans and functional imaging techniques are both highly valuable research tools. This review shows that when used together, they provide a wealth of information about brain activity during pain states and analgesia. These tools are promising candidates to help bridge the gap between animal and human studies, to improve translatability and provide opportunities for identification of new targets for back-translation to animal studies.

The prevalence of chronic pain in adolescents in Central Switzerland: A cross- sectional school-based study protocol

BACKGROUND

Chronic pain is associated with substantial personal suffering and societal costs and is a growing healthcare concern worldwide. While chronic pain has been extensively studied in adults, limited data exists on its prevalence and impact in adolescents. Understanding the prevalence and impact of chronic pain and pain beliefs in adolescents is crucial for developing effective prevention and treatment strategies. This study aims to estimate the prevalence, characteristics, and impact of chronic pain, and explore adolescents' knowledge and beliefs about pain.

METHODS

This is an observational cohort study of school-going adolescents aged 11 to 17 years in Central Switzerland. The study will estimate the point prevalence, characteristics (location, intensity, frequency, duration) and impact (PROMIS Pediatric Short Form v2.0 -Pain Interference Scale, PPIS) of chronic pain in school-going adolescents. We will also measure and investigate pupils' beliefs about pain (Concept of Pain Inventory (COPI)). Data will be collected through manual and digital self-report questionnaires and from participants in primary, secondary, and high schools between September 2023 and January 2024.

ANALYSES

The primary analyses will utilise descriptive statistics to estimate the point prevalence, characteristics, and impact of chronic pain. Secondary analyses will analyse associations and correlations between chronic pain, impact of pain and beliefs about pain.

OUTCOMES

This study will provide an estimate of the prevalence, characteristics and impact of chronic pain in adolescents in Central Switzerland and a measure of adolescents' understanding and beliefs about pain. In doing so, this study will provide insights into the scale of chronic pain as a public health concern. By understanding adolescents' pain beliefs and their influence on pain experience, this study can contribute to the development of educational approaches to enhance adolescents' knowledge and understanding of pain in order to optimise the prevention and treatment of chronic pain in adolescents. The findings may be useful to healthcare professionals and funders, policymakers, and researchers involved in the prevention, assessment, and treatment of pain in adolescents.

Assessing cognitive biases induced by acute formalin or hotplate treatment: an animal study using affective bias test

Pain, a universal and burdensome condition, influences numerous individuals worldwide. It encompasses sensory, emotional, and cognitive facets, with recent research placing a heightened emphasis on comprehending pain's impact on emotion and cognition. Cognitive bias, which encompasses attentional bias, interpretation bias, and memory bias, signifies the presence of cognitive distortions influenced by emotional factors. It has gained significant prominence in pain-related research. Human studies have shown that individuals experiencing pain exhibit cognitive bias. Similarly, animal studies have demonstrated cognitive bias in pain-induced states across various species and disease models. In this study, we aimed to investigate the memory bias displayed by rats experiencing acute pain, using the affective bias test (ABT) as a tool and administering either hotplate or formalin to induce acute pain. Our data showed that rats demonstrated a significant preference for the control treatment-related substrate over the substrate associated with formalin treatment (p < 0.001), an indication of the prominent memory bias stimulated by acute formalin injections. However, when exposed to substrates related to hotplate treatment and control treatment, the acute pain induced by the hotplate treatment failed to generate a statistically significant choice bias in rats (p = 0.674). Our study demonstrates that the negative emotions associated with acute pain can be reflected by memory bias in ABT, at least for formalin-induced acute pain. This finding will augment our comprehension of the emotional and cognitive aspects of acute pain.

The Nocebo Effect

Adverse nocebo responses can cause harm to patients and interfere with treatment adherence and effects in both clinic practice and clinical trials. Nocebo responses refer to negative outcomes to active medical treatments in clinical trials or practice that cannot be explained by the treatment's pharmacologic effects. Negative expectancies and nocebo effects are less known than placebo responses. Nocebo effects can be triggered by verbal suggestions, prior negative experiences, observation of others experiencing negative outcomes, and other contextual and environmental factors. As research advances over the years, mechanistic knowledge is accumulating on the neurobiological mechanisms of nocebo effects. This review summarizes studies on different facets of nocebo effects and responses and discusses clinical implications, ethical considerations, and future directions.

Flexibility Retained: Unimpaired Updating of Expectations in Schizophrenia

Flexibly and actively updating expectations based on feedback is crucial for navigating daily life. Previous research has shown that people with schizophrenia (PSZ) have difficulty adjusting their expectations. However, there are studies suggesting otherwise. To explore this further, we used a novel trial-based expectation updating paradigm called attribute amnesia. In the task, the participants needed to report the location of a target stimulus among distractors in pre-surprise trials. In the surprise trial, they were unexpectedly asked to report the identity of the target before reporting its location. Afterward, control trials were conducted whereby the participants were asked the same questions as in the surprise trial. Notably, the surprise trial and control trials were nearly identical, except that the participants expected to be asked about identity information in the control trials but not in the surprise trial. Thus, an improvement in identity reporting accuracy in the control trials in comparison with the surprise trial indicated active updating of expectations. In the current study, a total of 63 PSZ and 60 healthy control subjects (HCS) were enrolled. We found that both the PSZ and the HCS were unable to report information that they had fully attended to (i.e., identity) in the surprise trial. However, both groups showed a significant improvement in reporting identity information even in the first control trial. Critically, there was no significant difference in the magnitude of improvement between the two groups. The current findings indicate that PSZ have the ability to update their expectations as quickly and flexibly as HCS, at least in the context of the current task. The possible factors that might contribute to the discrepancy regarding expectation updating are discussed.

Pre-treatment expectations and their influence on subjective symptom change in Crohn's disease

BACKGROUND

Treatment expectations reportedly shape treatment outcomes, but have not been studied in the context of multimodal therapy in Crohn's disease (CD). Therefore, the current study investigated the role of treatment expectations for subjective symptom changes in CD patients who have undergone an integrative multimodal therapy program.

METHODS

Validated questionnaires were completed at the start of the treatment program and post intervention. Pre-treatment expectations and experienced symptom change were assessed with the Generic Rating Scale for Previous Treatment Experiences, Treatment Expectations, and Treatment Effects (GEEE); stress levels were quantified with the Perceived Stress Scale (PSS-10) and disease specific quality of life was quantified with the disease-specific Inflammatory Bowel Disease Questionnaire (IBDQ). We performed multiple linear and Bayesian regression to determine how expectations related to symptom change.

RESULTS

N = 71 CD patients (66.2% female) were included. Stronger expectations regarding symptom improvement (b = 0.422, t = 3.70, p < .001) were associated with higher experienced symptom improvement. Additionally, Bayesian analysis provided strong evidence for including improvement expectations as a predictor of improvement experience (BFinclusion = 13.78).

CONCLUSIONS

In line with research in other disorders, we found that positive treatment expectations were associated with experienced symptom improvement. In contrast, we found no indication that an experience of symptom worsening was associated with positive or negative baseline treatment expectations. Induction of positive expectations might be a potential avenue for improving treatment outcomes in CD therapy.

Personality change in a trial of psilocybin therapy v. escitalopram treatment for depression

BACKGROUND

Psilocybin Therapy (PT) is being increasingly studied as a psychiatric intervention. Personality relates to mental health and can be used to probe the nature of PT's therapeutic action.

METHODS

In a phase 2, double-blind, randomized, active comparator controlled trial involving patients with moderate-to-severe major depressive disorder, we compared psilocybin with escitalopram, over a core 6-week trial period. Five-Factor model personality domains, Big Five Aspect Scale Openness aspects, Absorption, and Impulsivity were measured at Baseline, Week 6, and Month 6 follow-up.

RESULTS

PT was associated with decreases in neuroticism (B = -0.63), introversion (B = -0.38), disagreeableness (B = -0.47), impulsivity (B = -0.40), and increases in absorption (B = 0.32), conscientiousness (B = 0.30), and openness (B = 0.23) at week 6, with neuroticism (B = -0.47) and disagreeableness (B = -0.41) remaining decreased at month 6. Escitalopram Treatment (ET) was associated with decreases in neuroticism (B = -0.38), disagreeableness (B = -0.26), impulsivity (B = -0.35), and increases in openness (B = 0.28) at week 6, with neuroticism (B = -0.46) remaining decreased at month 6. No significant between-condition differences were observed.

CONCLUSIONS

Personality changes across both conditions were in a direction consistent with improved mental health. With the possible exception of trait absorption, there were no compelling between-condition differences warranting conclusions regarding a selective action of PT (v. ET) on personality; however, post-ET changes in personality were significantly moderated by pre-trial positive expectancy for escitalopram, whereas expectancy did not moderate response to PT.

Graded brain fMRI response to somatic and visual acupuncture stimulation

Increased stimulation can enhance acupuncture clinical response; however, the impact of acupuncture stimulation as "dosage" has rarely been studied. Furthermore, acupuncture can include both somatic and visual components. We assessed both somatic and visual acupuncture dosage effects on sensory ratings and brain response. Twenty-four healthy participants received somatic (needle inserted, manually stimulated) and visual (needle video, no manual stimulation) acupuncture over the leg at three different dosage levels (control, low-dose, and high-dose) during functional magnetic resonance imaging (fMRI). Participants reported the perceived deqi sensation for each acupuncture dose level. Blood-oxygen-level dependent imaging data were analyzed by general linear model and multivariate pattern analysis. For both somatic and visual acupuncture, reported deqi sensation increased with increased dosage of acupuncture stimulation. Brain fMRI analysis demonstrated that higher dosage of somatic acupuncture produced greater brain responses in sensorimotor processing areas, including anterior and posterior insula and secondary somatosensory cortex. For visual acupuncture, higher dosage of stimulation produced greater brain responses in visual-processing areas, including the middle temporal visual areas (V5/MT+) and occipital cortex. Psychophysical and psychophysiological responses to both somatic and visual acupuncture were graded in response to higher doses. Our findings suggest that acupuncture response may be enhanced by the dosage of needling-specific and nonspecific components, represented by different neural mechanisms.

Fibromyalgia pain management effectiveness from the patient perspective: a qualitative evidence synthesis

PURPOSE

This qualitative evidence synthesis aimed to identify and integrate findings where adults with fibromyalgia discussed how they managed their pain, and their perceptions of prescribed treatments from healthcare professionals.

MATERIALS AND METHODS

A comprehensive search strategy was implemented in PubMed, Scopus, ISI Web of Science, and Cinahl Plus databases. The GRADE-CERQual framework was used to evaluate the findings confidence. The findings were analyzed using an inductive thematic analysis approach.

RESULTS

A total of 35 studies (N = 728) were included. The confidence in the findings ranged from high to low confidence. Patients with fibromyalgia often do not benefit from seeking medical attention due to provider stigma, and have varying views on medication effectiveness commonly reporting feeling like "walking chemists." They find mixed effects from exercise, and consider psychological support essential, although the benefits of cognitive-behavioral therapy were controversial. Combining cognitive-behavioral therapy with physical exercise appears more effective, while natural and complementary therapies have short-term benefits and high costs.

CONCLUSIONS

Pain management is a source for frustration and an unmet need for patients with fibromyalgia. The current findings provide crucial insight for providers and researchers; and support the need for fibromyalgia phenotyping and precision medicine approaches to pain management.Implications for RehabilitationChronic widespread pain is the defining feature of fibromyalgia, yet pain reduction is often an unmet need for these individuals.The lack of effective treatments resulting in long-term relief proves frustrating for patients and healthcare providers.Rehabilitation professional should consider the unique insight into this complex, heterogeneous condition that this qualitative synthesis provides to better understand their patient's perspective on pain management.Given the differing perspectives on pain treatment approaches individuals with fibromyalgia report, providers should discuss with each patient their current strategies and take a patient-centered, individualized approach to form an effective treatment plan.

Sham controls in device trials for chronic pain - tricky in practice-a review article

Background

Chronic pain affects one in four people and this figure is likely to increase further in line with an ageing population. Efforts to evaluate nonpharmacological interventions to support this patient population have become a priority for pain research. For device trials, the use of a sham control can add to the scientific validity and quality of a study. However, only a small proportion of pain trials include a sham control, and many are of poor quality. To facilitate the conduct of high-quality trials there is a need for a comprehensive overview to guide researchers within this area. The objective of this review was to synthesise the published data to address this need.

Methods

We identified studies that considered the evaluation, design, and conduct of sham-controlled trials in chronic pain by searching MEDLINE, CINAHL and Science Direct to November 2022. Studies that included sufficient content to inform the conduct/design of future research were included. An inductive thematic analysis approach was used to identify themes that require consideration when conducting sham-controlled trials. These are presented as a narrative review.

Results

37 articles were included. Identified themes related to the type of sham device, sham design, bias, study population and ethics.

Conclusions

To conduct good quality research the challenges surrounding the use of sham interventions need to be better considered. We highlight salient issues and provide recommendations for the conduct and reporting of sham-controlled device trials in chronic pain.

The Placebo Effect in Psychosis: Why It Matters and How to Measure It

Psychosis is characterized by unusual percepts and beliefs in the form of hallucinations and delusions. Antipsychotic medication, the primary treatment for psychosis, is often ineffective and accompanied by severe side effects, but research has not identified an effective alternative in several decades. One reason that clinical trials fail is that patients with psychosis tend to show a significant therapeutic response to inert control treatments, known as the placebo effect, which makes it difficult to distinguish drug effects from placebo effects. Conversely, in clinical practice, a strong placebo effect may be useful because it could enhance the overall treatment response. Identifying factors that predict large placebo effects could improve the future outlook of psychosis treatment. Biomarkers of the placebo effect have already been suggested in pain and depression, but not in psychosis. Quantifying markers of the placebo effect would have the potential to predict placebo effects in psychosis clinical trials. Furthermore, the placebo effect and psychosis may represent a shared neurocognitive mechanism in which prior beliefs are weighted against new sensory information to make inferences about reality. Examining this overlap could reveal new insights into the mechanisms underlying psychosis and indicate novel treatment targets. We provide a narrative review of the importance of the placebo effect in psychosis and propose a novel method to assess it.

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.

Placebo treatment affects brain systems related to affective and cognitive processes, but not nociceptive pain

Placebo analgesia is a replicable and well-studied phenomenon, yet it remains unclear to what degree it includes modulation of nociceptive processes. Some studies find effects consistent with nociceptive effects, but meta-analyses show that these effects are often small. We analyzed placebo analgesia in a large fMRI study (N = 392), including placebo effects on brain responses to noxious stimuli. Placebo treatment caused robust analgesia in both conditioned thermal and unconditioned mechanical pain. Placebo did not decrease fMRI activity in nociceptive pain regions, including the Neurologic Pain Signature (NPS) and pre-registered spinothalamic pathway regions, with strong support from Bayes Factor analyses. However, placebo treatment affected activity in pre-registered analyses of a second neuromarker, the Stimulus Intensity Independent Pain Signature (SIIPS), and several associated a priori brain regions related to motivation and value, in both thermal and mechanical pain. Individual differences in behavioral analgesia were correlated with neural changes in both thermal and mechanical pain. Our results indicate that processes related to affective and cognitive aspects of pain primarily drive placebo analgesia.

Task-dependent functional connectivity of pain is associated with the magnitude of placebo analgesia in pain-free individuals

BACKGROUND

Task-based functional connectivity (FC) of pain-related regions resulting from expectancy-based placebo induction has yet to be examined, limiting our understanding of regions and networks associated with placebo analgesia.

METHODS

Fifty-five healthy pain-free adults over 18 (M = 22.8 years, SD = 7.75) were recruited (65.5% women; 63.6% non-Hispanic/Latino/a/x; 58.2% White). Participants completed a baseline followed by a placebo session involving the topical application of an inactive cream in the context of an expectancy-enhancing instruction set. Noxious heat stimuli were applied to the thenar eminence of the right palm using an fMRI-safe thermode. Stimulus intensity was individually calibrated to produce pain ratings of approximately 40 on a 100-point visual analogue scale.

RESULTS

A total of 67.3% of the participants showed a reduction in pain intensity in the placebo condition with an average reduction in pain across the whole sample of 12.7%. Expected pain intensity was associated with reported pain intensity in the placebo session (b = 0.32, p = 0.004, R2  = 0.15). Voxel-wise analyses indicated seven clusters with significant activation during noxious heat stimulation at baseline (pFDR  < 0.05). Generalized psychophysiological interaction analysis suggested that placebo-related FC changes between middle frontal gyrus-superior parietal lobule during noxious stimulation were significantly associated with the magnitude of pain reduction (pFDR  < 0.05).

CONCLUSIONS

Results suggest that stronger expectancy-based placebo responses might be underpinned by greater FC among attentional and somatosensory regions.

SIGNIFICANCE

This article provides support and insight for task-dependent functional connectivity differences related to the magnitude of placebo analgesia. Our findings provide key support that the magnitude of expectation-based placebo response depends on the coupling of regions associated with somatosensory and attentional processing.

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.

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

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

The Importance of the Treatment Rationale for Pain in Animal-Assisted Interventions: A Randomized Controlled Trial in Healthy Participants

Animal-assisted interventions (AAIs) is a promising treatment approach for pain, but possible mechanisms still need to be elucidated. This study set out to investigate the analgesic effects of an animal provided with a treatment rationale in a randomized controlled trial employing a standardized experimental heat-pain paradigm. We randomly assigned 128 healthy participants to: dog treatment (DT), placebo treatment (PT), dog and placebo treatment (DPT), and no treatment (NT). Primary outcomes were heat-pain tolerance and the corresponding self-reported ratings of pain unpleasantness and intensity. Results revealed no differences in heat-pain tolerance between the conditions. However, participants in the DT condition experienced heat-pain as significantly less unpleasant at the limit of their tolerance compared to participants in the NT condition (estimate = -0.96, CI = -1.58 to 0.34, P = .010). Participants in the DT condition also showed lower ratings of pain intensity at the limit of their tolerance compared to participants in the NT condition (estimate = -0.44, CI = -0.89 to 0.02, P = .060). This study indicates that a dog has analgesic effects on pain perception when integrated into the treatment rationale. We assume that providing a treatment rationale regarding the animal is important in AAIs for pain. PERSPECTIVE: This study shows that the presence of an animal is not sufficient for animal-assisted interventions (AAIs) to have an analgesic effect on pain unless they are provided with a treatment rationale. This could imply that not only the animal but also contextual factors are important in AAIs. TRIAL REGISTRATION: Clinical Trials NCT04361968.

Investigating the hypoalgesic effects of spinal manipulative therapy using hidden pain conditioning and positive expectation in patients with chronic low back pain: protocol for a randomised controlled trial

INTRODUCTION

Placebo effects are responses capable of modulating pain and influencing treatment response. Two mechanisms are commonly related to placebo effects: expectations and conditioning. However, the research in this field is focused on laboratory studies with healthy participants. This study aims to identify whether a conditioning procedure with positive induced expectations about spinal manipulative therapy (SMT) will result in greater hypoalgesic effects in adults with chronic low back pain (CLBP) in a clinical trial design.

METHODS AND ANALYSIS

This trial will enrol 264 patients with non-specific CLBP, aged 18-60 years. Patients will undergo a calibration test to determine the thermal pain threshold for the hidden pain conditioning procedure. Afterward, they will be randomised to one of the three groups: hidden pain conditioning with positive induced expectations-group one (G1); positive expectations-group two (G2) and neutral expectations-group three (G3). Patients will receive instructions to manipulate the expectations. The pretreatment heat pain test will be performed before the SMT and after the intervention patients will undergo again the heat pain intensity test. However, only patients in G1 will receive hidden pain conditioning to reinforce the association between SMT and pain intensity reduction. All patients will undergo five sessions of SMT. The outcomes will be assessed immediately after the last session and at the 6 weeks and 3-month follow-ups. All statistical analyses will be conducted following intention-to-treat principles, and the treatment effects will be determined with linear mixed models.

ETHICS AND DISSEMINATION

The Federal University of São Carlos approved this research (Process n° 52359521.1.0000.5504). All participants will give written informed consent. Dissemination of the results will include publications in peer-reviewed journals and presentations at conferences. If positive expectations and classical conditioning improve outcomes, it may support the administration of such intervention.

TRIAL REGISTRATION NUMBER

NCT05202704.

Psychophysical pain encoding in the cingulate cortex predicts responsiveness of electrical stimulation

Background

The anterior cingulate cortex (ACC) plays an important role in the cognitive and emotional processing of pain. Prior studies have used deep brain stimulation (DBS) to treat chronic pain, but results have been inconsistent. This may be due to network adaptation over time and variable causes of chronic pain. Identifying patient-specific pain network features may be necessary to determine patient candidacy for DBS.

Hypothesis

Cingulate stimulation would increase patients' hot pain thresholds if non-stimulation 70-150 Hz activity encoded psychophysical pain responses.

Methods

In this study, four patients who underwent intracranial monitoring for epilepsy monitoring participated in a pain task. They placed their hand on a device capable of eliciting thermal pain for five seconds and rated their pain. We used these results to determine the individual's thermal pain threshold with and without electrical stimulation. Two different types of generalized linear mixed-effects models (GLME) were employed to assess the neural representations underlying binary and graded pain psychophysics.

Results

The pain threshold for each patient was determined from the psychometric probability density function. Two patients had a higher pain threshold with stimulation than without, while the other two patients had no difference. We also evaluated the relationship between neural activity and pain responses. We found that patients who responded to stimulation had specific time windows where high-frequency activity was associated with increased pain ratings.

Conclusion

Stimulation of cingulate regions with increased pain-related neural activity was more effective at modulating pain perception than stimulating non-responsive areas. Personalized evaluation of neural activity biomarkers could help identify the best target for stimulation and predict its effectiveness in future studies evaluating DBS.

From past pain to future pain through the pain of others: Information about other people's pain ratings can alleviate our subsequent pain

BACKGROUND

Previous studies have shown that pain memories have a profound impact on subsequent pain experiences. This study investigated whether pain ratings derived from other people can modify an individual's memory of past pain. This study also examined whether pain memory modified by others' pain ratings determines subsequent pain experiences.

METHODS

Participants were divided into two groups: an experimental group and a control group. Participants in both groups were exposed to pain stimulation; then, they recalled its intensity twice over a period of time; after a break, they were again exposed to pain stimulation of the same intensity. The final sample consisted of 53 participants. The only difference between the experimental group and the control group was that in the former the pain ratings of other alleged participants were presented between the two consecutive pain recalls. These ratings suggested that other people experienced the same pain as less intense.

RESULTS

The pain ratings derived from other people did not alter the pain memory; nevertheless, they affected an individual's next pain experience even for a certain period of time after their presentation. This type of pain-related information shaped participants' subsequent pain experiences regardless of their empathy, conformity, and susceptibility to social influence.

CONCLUSIONS

Information on pain derived from other people not only shapes the response to a novel stimulation but also substantially modifies the subsequent experience of that stimulation.

SIGNIFICANCE

The study demonstrates the importance of social information on pain and provides evidence that this type of information substantially modifies the subsequent experience of the same pain. These results suggest that social information on pain can be used to alleviate pain associated with recurring medical procedures and thus increase patients' willingness to continue treatment.

Harnessing the placebo effect to enhance emotion regulation effectiveness and choice

The placebo effect demonstrates how positive expectancies shape the effectiveness of various treatments. Across studies, placebo treatments are interventions (creams, pills, etc.) that are presented to individuals as, and are learned to be, beneficial for them. This study tested whether placebo-induced expectancies can be harnessed to improve individuals' internal emotion regulation attempts. Participants implemented two types of distraction, an emotion regulation strategy involving attentional disengagement, to attenuate fear of pain. In a typical conditioning paradigm, the placebo-distraction was introduced as an effective strategy (verbal suggestion) and was surreptitiously paired with reduced pain (conditioning), whereas the control-distraction was introduced as noneffective and was surreptitiously paired with increased pain. As predicted, we found that during a later test phase, where pain intensity was identical, the placebo-distraction resulted in reduced self-reported fear of pain, relative to the control-distraction. Moreover, we utilized a robust behavioral choice measure, demonstrating increased preferences for the placebo-distraction. We additionally tested whether these effects generalize to a different emotional context of fear of unpleasant pictures. In that context, the placebo-distraction was as effective as the control-distraction, but was substantially preferred. This study demonstrates that the placebo effect can be expanded to include individuals' internal attempts to influence their conditions.

Wenn aus einem Bauchgefühl viszerale Schmerzen werden: Placebo- und Nocebo-Mechanismen entlang der Darm-Hirn-Achse

Das Erleben von Schmerz ist nach heutigem Verständnis durch eine Vielzahl biologischer, psychologischer und sozialer Faktoren geprägt und somit eine komplexe, von der Nozizeption abzugrenzende, psychologische Erfahrung. Entsprechend ist das Schmerzerleben durch psychologische Faktoren modulierbar und chronische Schmerzen werden als biopsychosoziale Erkrankungen verstanden. Dies gilt auch für den Viszeralschmerz, dem spezifische psychophysiologische Prinzipien und neurobiologische Mechanismen zugrunde liegen, was eine interdisziplinäre Betrachtung unter Einbeziehung der Psychologie und der Neurowissenschaften erforderlich macht. Ausgehend von den bidirektionalen Verbindungen zwischen Darm und Hirn und aufbauend auf einem biopsychosozialen Krankheitsmodell beschreibt dieser Übersichtsbeitrag psychologische Mechanismen, die bei der Entstehung, Aufrechterhaltung und Therapie viszeraler Schmerzen wichtig sind. Dabei liegt der Fokus auf positiven und negativen Erwartungseffekten im psychosozialen Behandlungskontext. Therapieerwartungen können Krankheitssymptome sowohl positiv als auch negativ beeinflussen. Diese gemeinhin als Placebo- und Noceboeffekte bekannten Phänomene, die durch die Arzt-Patient Kommunikation, Lernprozesse, Stress und Furcht vermittelt werden, sind auch für den Viszeralschmerz bei gastrointestinalen Erkrankungen zunehmend anerkannt und Gegenstand aktueller grundlagenwissenschaftlicher und klinischer Forschungsaktivitäten. Neue interdisziplinäre und translationale Forschungsansätze aus der Forschung zu Placebo- und Noceboeffekten liefern spannende Einblicke in die zahlreichen Verbindungen und Wechselbeziehungen zwischen Darm und Gehirn bei normalen wie auch pathologischen Darm-Hirn Interaktionen und können dazu beitragen, die Pathophysiologie von Erkrankungen, die mit viszeralen Schmerzen einhergehen, besser zu verstehen und wichtige Erkenntnisse für neue Therapieansätze zu gewinnen.

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.

Impact of media coverage on side effect reports from the COVID-19 vaccine

OBJECTIVE

Past research shows that media coverage of medicine side effects can produce a nocebo response. New Zealand news media discussed myocarditis following the Pfizer COVID-19 vaccine. This study examined whether side effects mentioned in the media increased compared to control symptoms not mentioned.

METHODS

The study analysed 64,086 vaccine adverse reaction reports, retrieved from the medicine safety authority. Generalised linear regressions compared the side effect rate during three discrete periods of media reporting (August 2021, December 2021, April 2022) with the pre-media baseline rate. The outcomes were weekly reports of chest discomfort, monthly reports of chest, heart and breathing symptoms, and myocarditis, pericarditis, and anxiety. Control symptoms were fever, numbness, and musculoskeletal pain. Logistic regressions investigated factors associated with side effect reporting.

RESULTS

The reporting rate of chest discomfort was 190% greater in the five weeks after the first media item (p < .001). The monthly reporting rates of the symptoms mentioned in the media were significantly greater after the news coverage (ps ≤ 0.001). There was no effect of media on the control side effect fever (p = .06). There was an effect of media on myocarditis, pericarditis and anxiety (ps < 0.001). Anxiety, male gender, and younger age were significantly associated with side effects.

CONCLUSION

The results indicate that a media-induced nocebo response occurred. This is most likely due to increased expectations and awareness of COVID-19 vaccine side effects, elevated symptom experience from anxiety, and consequently greater reporting of the symptoms in line with the media coverage.

Placebo and nocebo effects: from observation to harnessing and clinical application

Placebo and nocebo effects are salubrious benefits and negative outcomes attributable to non-specific symbolic components. Leveraging advanced experimental and analytical approaches, recent studies have elucidated complicated neural mechanisms that may serve as a solid basis for harnessing the powerful self-healing and self-harming capacities and applying these findings to improve medical practice and minimize the unintended exacerbation of symptoms in medical practice. We review advances in employing psychosocial, pharmacological, and neuromodulation approaches to modulate/harness placebo and nocebo effects. While these approaches show promising potential, translating these research findings into clinical settings still requires careful methodological, technical, and ethical considerations.

Targeting neural correlates of placebo effects

Harnessing the placebo effects would prompt critical ramifications for research and clinical practice. Noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation and multifocal transcranial electric stimulation, could manipulate the placebo response by modulating the activity and excitability of its neural correlates. To identify potential stimulation targets, we conducted a meta-analysis to investigate placebo-associated regions in healthy volunteers, including studies with emotional components and painful stimuli. Using biophysical modeling, we identified NIBS solutions to manipulate placebo effects by targeting either a single key region or multiple connected areas. Moving to a network-oriented approach, we then ran a quantitative network mapping analysis on the functional connectivity profile of clusters emerging from the meta-analysis. As a result, we suggest a multielectrode optimized montage engaging the connectivity patterns of placebo-associated functional brain networks. These NIBS solutions hope to provide a starting point to actively control, modulate or enhance placebo effects in future clinical studies and cognitive enhancement studies.

A digital application and augmented physician rounds reduce postoperative pain and opioid consumption after primary total knee replacement (TKR): a randomized clinical trial

BACKGROUND

Severe postoperative pain not only is a considerable burden for patients but also leads to overprescription of opioids, resulting in considerable health concerns. The remarkable development of new technologies in the health care system provides novel treatment opportunities in this area and could exploit the additional placebo effect, provide added value for patients, and at the same time support hospital staff. We aimed to test the pain- and opioid intake-reducing effects of enhanced postoperative pain management by boosting pain medication by using a technical application and/or augmented physician rounds.

METHODS

In a four-arm, randomized clinical trial, 96 patients (24 patients per group) scheduled for a total knee replacement (TKR) were randomized into four groups for four postoperative days: an "application" group (APP) with information via an iPad-based application; a "doctor" group (DOC) with augmented physician rounds; a combination group (APP+DOC), which received both interventions; and a "treatment as usual" group (TAU) as a baseline with no additional intervention besides the standard care which consists of standardized medication, regular physician rounds, and physiotherapy. Postoperative pain and opioid requirements pre- and postoperatively until hospital discharge were recorded.

RESULTS

The difference between post- and preoperative pain was significantly different between the groups (P=.02, partial η²=.10). APP+DOC experienced greater postoperative pain relief than DOC (mean: 2.3 vs. 0.7, 95% CI: 0.08-3.09; P=.04) and TAU (mean 2.3 vs. 0.1; 95% CI: 0.69-3.71; P=.005), respectively, the difference compared to APP (mean 2.3 vs. 1.7; 95% CI -1.98-1.76) was not significant. Opioid consumption differed significantly between groups (P=.01, partial η²=.12). APP+DOC (72.9 mg) and DOC (75.4 mg) consumed less oxycodone than APP (83.3 mg) and TAU (87.9 mg; 95% CI: 2.9-22.1; P=.003). APP+DOC consumed significantly less oxycodone than DOC (d=0.2-0.4). There were no significant group differences in NSAID and Morphine sulfate consumption. Patients in APP+DOC were more satisfied with their treatment than patients in TAU (P=.03, partial η²=.09).

CONCLUSIONS

The combination of an innovative digital app, which implements open drug administration and augmented physician rounds that support the doctor-patient relationship can significantly improve postoperative pain management.

TRIAL REGISTRATION

The protocol was approved by the local ethics committee of the ethical commission of the German Psychological Society (Deutsche Gesellschaft für Psychologie; DGPs). The study was registered at DRKS.de (identifier: DRKS00009554).

Sex differences in associations between delay discounting and expectancies for alcohol analgesia

Self-medication of pain with alcohol is prevalent, and expectancies for alcohol analgesia likely influence pain relief and alcohol consumption. Hazardous alcohol use has been associated with greater delay discounting rates; however, little is known about the relationship between delay discounting and expectancies for alcohol analgesia. Therefore, the present study examined sex differences in associations between delay discounting and expectancies for alcohol analgesia. Healthy drinkers without chronic pain (N = 53) completed measures of expectancies for alcohol analgesia, alcohol use, and alcohol outcome expectancies. A five-trial adjusting-delay discounting task (DDT) for monetary outcomes was also administered. Regression analyses revealed that sex moderated the relationship between delay discounting and expectancies for alcohol analgesia. Steeper delay discounting rates were associated with weaker expectancies for alcohol analgesia among men when adjusting for average alcohol consumption. Among women, nonsignificant associations between delay discounting rates and expectancies for alcohol analgesia were observed. These findings provide initial evidence of sex differences in associations between delay discounting and expectancies for alcohol analgesia. The directionality of these associations was unexpected and may have implications for patterns of self-medication with alcohol. (PsycInfo Database Record (c) 2022 APA, all rights reserved).