Relieving patients' pain with expectation interventions: a meta-analysis

Moderators of nocebo effects in controlled experiments: A multi-level meta-analysis

Nocebo effects are a heterogenous phenomenon in which contextual cues trigger or exacerbate symptoms independently of active interventions. Suggestion, conditioning, and social observation are widely recognised as hallmark methods for inducing nocebo effects, but the extent to which nocebo effects are differentially influenced by suggestion type (e.g., direct or indirect suggestion) and mode of administration (e.g., verbal, textual, visual, etc.) across symptom domains remains unknown. We conducted a pre-registered meta-analysis (PROSPERO registration number CRD42023402097) to quantitatively synthesize available research on the factors that moderate effects in controlled nocebo experiments. Of 8469 search results, 105 experiments comprising 5017 participants and 391 effect sizes were analyzed. A multi-level meta-analysis revealed an overall moderate effect size for nocebo effects, g=0.50, [0.39, 0.62]. The magnitude of symptom expectancy effects was a significant moderator of nocebo effects. Verbal suggestion and social observation yielded moderate and comparable nocebo effects whereas technological devices, sham stimulation, and conditioning were independently associated with the induction of large nocebo effects. Greater specificity in the reporting of nocebo induction methods is required to elucidate the efficacy of different types of suggestions in inducing nocebo effects.

Prior therapeutic experiences and treatment expectations are differentially associated with pain-related disability in individuals with chronic pain

Many individuals suffering from chronic pain do not benefit sufficiently from treatment. Prior treatment experiences and treatment expectations play a significant role in perceived symptom severity and treatment-related outcomes in many chronic diseases. Their role in chronic pain, however, remains underexplored. Therefore, the present study investigated the role of treatment experiences and treatment expectations for pain-related disability in individuals suffering from chronic pain. Participants suffering from chronic pain who were receiving treatment (pharmacotherapy, physiotherapy, and/or psychotherapy) completed questionnaires as part of an online survey. Prior improvement, worsening, and side effect experiences and their relation with treatment expectations were assessed with the generic rating scale for previous treatment experiences, treatment expectations, and treatment effects (GEEE), and pain-related disability via the pain disability questionnaire (PDI). Multiple linear regressions were performed to determine how prior treatment experiences related to treatment expectations and whether prior experiences and current treatment expectations were associated with pain-related disability. In total, 212 participants (86.3% female) were included. Prior worsening experience as well as stronger worsening and side effect expectations were associated with higher pain-related disability. Screening patients for different expectation domains could be an important strategy to detect and target potentially relevant factors influencing pain-related disability and treatment outcome.

EEG oscillations reveal neuroplastic changes in pain processing associated with long-term meditation

The experience of pain is a combined product of bottom-up and top-down influences mediated by attentional and emotional factors. Meditation states and traits are characterized by enhanced attention/emotion regulation and expanded self-awareness that can be expected to modify pain processing. The main objective of the present study was to explore the effects of long-term meditation on neural mechanisms of pain processing. EEG pain-related oscillations (PROs) were analysed in highly experienced practitioners and novices during a non-meditative resting state with respect to (a) local frequency-specific and temporal synchronizing characteristics to reflect mainly bottom-up mechanisms, (b) spatial synchronizing patterns to reflect the neural communication of noxious information, (c) pre-stimulus oscillations to reflect top-down mechanisms during pain expectancy, and (d) the P3b component of the pain-related potential to compare the emotional/cognitive reappraisal of pain events by expert and novice meditators. Main results demonstrated that in experienced (long-term) meditators as compared to non-experienced (short-term) meditators (1) the temporal and spatial synchronizations of multispectral (from theta-alpha to gamma) PROs were substantially suppressed at primary and secondary somatosensory regions contra-lateral to pain stimulation within 200 ms after noxious stimulus; (2) pre-stimulus alpha activity was significantly increased at the same regions, which predicted the suppressed synchronization of PROs in long-term meditators; (3) the decrease of the P3b component was non-significant. These novel observations provide evidence that even when subjected to pain outside of meditation, experienced meditators exhibit a pro-active top-down inhibition of somatosensory areas resulting in suppressed processing and communication of sensory information at early stages of painful input. The emotional/cognitive appraisal of pain is reduced but remains preserved revealing a capacity of experienced meditators to dissociate pro-active and reactive top-down processes during pain control.

Treatment expectations and pain-related outcomes in clinical trials of digital cognitive-behavioral therapy for youth with chronic pain

Treatment expectations (TE) are predictive of patient outcomes in clinical practice and suggested to moderate treatment responses in chronic pain clinical trials. However, evidence is mainly derived from studies conducted with adult populations with musculoskeletal pain, primarily focused on pharmacological treatments and a few alternative intervention modalities (e.g., acupuncture). We examined the role of pretreatment TE in youth participating in two randomized controlled trials of digital cognitive-behavioral therapy (CBT) for chronic pain-the WebMAP2 Trial of youth with chronic primary pain (n = 273) and the iCC-SCD Trial of youth with sickle cell pain (n = 111). Specifically, we tested: 1) whether controlling for TE enhanced the detection of treatment efficacy, 2) the main effect of TE in predicting pain-related outcomes over time (regardless of treatment assignment), and 3) the effect of TE in moderating treatment efficacy (digital CBT vs education control). Findings indicated that adjusting for pretreatment TE did not enhance the ability to detect treatment efficacy. In the WebMAP2 Trial, higher pretreatment TE were associated with greater reductions in anxiety and lower CBT efficacy (relative to education control) in improving depressive and anxiety symptoms. In the iCC-SCD Trial, higher pretreatment TE were associated with greater improvement in mobility and enhanced CBT efficacy (relative to education control) for improving mobility. Overall, higher pretreatment TE were associated with better functioning over time, though the specific domains of improvement and the moderating effects on treatment efficacy somewhat differed between youth with primary and sickle cell-related chronic pain. PERSPECTIVE: Incorporating TE into clinical assessments and ensuring consistent collection, reporting, and analysis in clinical trials are crucial for identifying potential heterogeneous treatment responses. Standardizing TE measures for youth with chronic pain and considering population characteristics are important for understanding TE's role in treatment responses.

The impact of dietary claims on behaviour: Expectations qualify how actual satiety affects cognitive performance

Dietary choices significantly impact health and daily cognitive performance, prompting various recommendations for eating habits. Whereas much research has focused on the effects of actual satiety on cognitive performance, the influence of expectations regarding effects of satiety on performance remains underexplored. This study aims to address this gap by examining how the expectation of satiety influences cognitive outcomes, building on existing findings that highlight the role of placebo effects in shaping eating behaviour. This study manipulated participants' expectations of how their satiety (satiated versus hungry) affects their concentration through verbal placebo suggestions and measured effects on their cognitive performance. The sample consisted of four groups who were either satiated or hungry and either read the suggestion that their satiety state enhances or deteriorates their concentration. The suggestion was formulated as a scientific finding. Cognitive performance was measured remotely using a Simon Task. Results showed that if participants' actual satiety state was paired with a positive expectation regarding the state they were in, their performance was better than if it was paired with a negative expectation regarding their current satiety state. So, actual satiety state was not the main driver of cognitive performance, but what participants were led to believe about their current satiety state was. These findings suggest that instructions in intervention studies should be phrased carefully to avoid expectation-related confounds. Additionally, verbal placebo suggestions could be a promising method to enhance cognitive performance in daily life.

Do patients with fibromyalgia syndrome and healthy people differ in their opinions on placebo effects in routine medical care?

OBJECTIVES

Placebo effects can relieve acute and chronic pain in both research and clinical treatments by learning mechanisms. However, the application of placebo-based treatment strategies in routine medical care is questioned. The current study investigated the opinions of patients with fibromyalgia and healthy controls regarding learning of placebo effects and their practical applications.

METHOD

An online survey asked 158 age- and sex-matched adult patients and controls (79 per group) to rate the perceived influence of various placebo learning mechanisms on pain relief, and the acceptability and perceived effectiveness of placebo-based strategies (open-label, closed-label, dose-extending, and treatment-enhancing strategies). Respondents' knowledge about placebo effects was obtained through a 7-item quiz.

RESULTS

The groups did not differ in the perceived influence of placebo learning mechanisms on pain relief (p = 0.217). Controls considered closed-label and treatment-enhancing strategies more acceptable than patients (p = 0.003 and p < 0.001), whereas controls perceived all strategies more effective. In both groups, closed-label strategies were significantly less acceptable than any other strategy (p-values < 0.001), and treatment-enhancing or dose-extending strategies were most acceptable. Higher acceptability was predicted by higher perceived effectiveness ratings (p < 0.001). Also, increased placebo knowledge was related to higher acceptability (p = 0.03) and perceived effectiveness (p < 0.001).

DISCUSSION

This survey suggests that both the medical history of patients and knowledge about placebo effects affect the acceptability and perceived effectiveness of placebo-based strategies. Furthermore, strategies that are transparent, assumed effective, or combined with existing medical treatments are deemed most acceptable. Keeping these factors in mind is essential for the clinical implementation of placebo-based strategies in routine medical care.

Turkish cross-cultural adaptation, construct validity, and reliability of the Treatment Expectations in Chronic Pain Scale

BACKGROUND

Measuring treatment expectations using the Treatment Expectations in Chronic Pain (TEC) scale has the potential to help clinicians and researchers better understand the role that treatment expectations play within the framework of multimodal pain management settings.

OBJECTIVE

The purpose of this study is to determine the cross-cultural adaptation, construct validity and reliability of the TEC Scale in the Turkish language.

METHODS

The study included 191 volunteers aged 22-65 with chronic musculoskeletal diseases. This study composed of a six-stage cross-cultural adaptation process, which included translation, translation synthesis, back-translation, expert committee review, pre-testing and documentation submission. The Positivity Scale and Illness Cognition Questionnaire were used to measure convergent validity while the Hospital Anxiety and Depression Scale was used to test divergent validity. The psychometric properties of the Turkish version of the TEC scale was examined by confirmatory factor analysis (CFA). Scale's internal consistency was examined using Cronbach's alpha. Pearson correlation coefficients were utilized to evaluate both convergent and divergent validity. The significance level was set at p < .05.

RESULTS

The results of the CFA showed that factor structure of predicted subscale fitted well the data (x2/df = 3,07;CFI = 0,91,IFI = 0,91 TLI = 0,87,RMSEA = 0,10). The results of the CFA indicated that factor structure of ideal subscale fitted well with the data (x2/df = 2,38;CFI = 0,92,IFI = 0,93,TLI = 0,90,RMSEA = 0,08). Both subscales of the TEC were strongly correlated. The predicted subscale had moderate relationships to depression, anxiety, and positivity (r = -0.37 to r = 0.55) but poor correlations with measures of acceptance, perceived benefits and helplessness (r = -0.24 to 0.35). The ideal subscale had moderate correlations with measures of positivity (r = 0.36) and depression (r = -0.38) but poor correlations with measures of acceptance, perceived benefits helplessness and anxiety (r = 0.14).

CONCLUSIONS

The Turkish version of the TEC scale is acceptable, valid, and reliable for use in Turkish patients with chronic musculoskeletal pain in physiotherapy outpatient practice.

Patient perspectives on low back pain treatment in primary care: a qualitative study of hopes, expectations, and experiences

BACKGROUND

Patients' hopes and expectations for low back pain treatment influence their consultation experiences and treatment outcomes. These hopes and expectations may evolve over time, potentially leading to a shift in what patients consider important before and after a consultation. Understanding the distinction between hopes and expectations, and how they evolve is important for improving patient care. This study explored patients' hopes and expectations prior to LBP consultations and examined how these were reflected in their post-consultation experiences.

METHODS

We employed a qualitative design consisting of individual semi-structured pre- and post-consultation interviews with patients seeking care for low back pain from general practitioners, physiotherapists, and chiropractors in Denmark. A convenience sample of 18 patients (10 females and 8 males) aged between 28 and 79 years were interviewed about their hopes and expectations before a consultation and their experiences immediately following the consultation. Data were analysed employing Braun and Clarke's thematic analysis.

RESULTS

Two themes with five subthemes were developed: (1) "Something needs to be done," which included subthemes related to life disruption, expectations of clinical assessment, and the clinicians as experts; and (2) "Experiences and emotional responses to the interaction with the clinician", highlighting the importance of trust and the personal attributes of clinicians. Patients initially sought urgent help and clarity regarding their condition but shifted their focus post-consultation to the relational dynamics and emotional engagement experienced during interactions with clinicians.

CONCLUSIONS

This study contributes to the understanding of how patients' hopes and expectations regarding low back pain consultations evolve, shifting from a focus on clinical actions and outcomes to valuing interpersonal relationships and emotional support from clinicians. Recognising these shifts can enhance clinician-patient interactions and improve overall patient satisfaction and treatment outcomes.

CLINICAL TRIAL NUMBER

Not applicable.

A randomized trial investigating the impact of response expectancy on the counting blessings intervention: the role of optimism as a moderator

Introduction

This randomized controlled trial aimed to address a knowledge gap concerning the mechanisms responsible for the efficacy of gratitude interventions. Specifically, we investigated how various response expectancies (positive, ambiguous + negative, and no expectancy) impact the efficacy of the "counting blessings" intervention in influencing positive and negative emotions. Additionally, the study explores how optimism levels (high, medium, low) interact with these expectancies to influence intervention efficacy.

Method

A total of 529 adult volunteers were recruited through social media and randomly assigned to one of three experimental conditions, Positive Condition (PC), Ambiguous + Negative Condition (ANC), No Expectancy Condition (NEC), using a Random Sequence Generator. Of these, 142 participants completed the seven-day counting blessings intervention, and 111 participated in a follow-up assessment 1 month later. Missing data were addressed using multiple imputation. The main outcomes were changes in positive and negative emotions, with moderation analysis assessing the interaction between optimism levels and response expectancies. The study adhered to the CONSORT guidelines.

Results

While no significant interaction was found between experimental conditions and time regarding emotional outcomes (p ˃ 0.05), moderation analysis revealed differential interactions between optimism levels and expectancies, particularly influencing positive emotions (p < 0.009). For participants with low optimism, positive emotions significantly increased from post-intervention to follow-up in the PC (t = -2.42, p < 0.016) and from pre-intervention to post-intervention in the ANC (t = 2.41, p < 0.018). Participants with medium optimism experienced an increase in positive emotions across all conditions from pre-intervention to follow-up and from post-intervention to follow-up (ps  < 0.05). High optimism participants showed an increase in positive emotions from pre-intervention to follow-up and post-intervention to follow-up in the PC (t = 2.09, p < 0.038 and t = 3.06, p < 0.003) and NEC c (t = -2.76, p < 0.006 and t = 2.74, p < 0.007).

Conclusion

Our findings emphasize the effectiveness of a brief gratitude journal and underscore the nuanced role of response expectancy, especially in interaction with the initial level of optimism, in enhancing positive emotions. These results hold significance for both theoretical understanding and clinical applications.

Psilocybin-assisted neurofeedback for the improvement of executive functions: a randomized semi-naturalistic-lab feasibility study

Executive function deficits, common in psychiatric disorders, hinder daily activities and may be linked to diminished neural plasticity, affecting treatment and training responsiveness. In this pioneering study, we evaluated the feasibility and preliminary efficacy of psilocybin-assisted frontal-midline theta neurofeedback (NF), a neuromodulation technique leveraging neuroplasticity, to improve executive functions (EFs). Thirty-seven eligible participants were randomized into an experimental group (n = 18) and a passive control group (n = 19). The experimental group underwent three microdose sessions and then three psilocybin-assisted NF sessions, without requiring psychological support, demonstrating the approach's feasibility. NF learning showed a statistical trend for increases in frontal-midline theta from session to session with a large effect size and non-significant but medium effect size dynamical changes within sessions. Placebo effects were consistent across groups, with no tasks-based EF improvements, but significant self-reported gains in daily EFs-working memory, shifting, monitoring and inhibition-showing medium and high effect sizes. The experimental group's significant gains in their key training goals underscored the approach's external relevance. A thorough study with regular sessions and an active control group is crucial to evaluate EFs improvement and their specificity in future. Psilocybin-enhanced NF could offer significant, lasting benefits across diagnoses, improving daily functioning. This article is part of the theme issue 'Neurofeedback: new territories and neurocognitive mechanisms of endogenous neuromodulation'.

The Ethics of Placebo

This article reviews the ethical implications related to the use of placebos in clinical practice and clinical trials. We discuss evidence for placebo effects, the role of placebo in research and clinical practice, and related ethical issues. It also provides an overview of some of the new findings related to research involving placebos and the possible associated ethical challenges.

Development and validation of the General attitude towards Medication Questionnaire (GAMQ)

BACKGROUND

Attitudes towards medication can affect treatment outcomes and adherence through mechanisms such as placebo and nocebo effects. Questionnaires assessing both negative and positive attitudes towards medication in general, which can be used across a variety of settings and in both patient and non-patient samples, are however lacking. To fill this gap, we developed and validated the General Attitude towards Medication Questionnaire (GAMQ).

METHODS

Items were selected and adapted from existing questionnaires by a group of experts. Validation of the original Dutch version took place in 4 samples: 2 recruited from the general population (n = 508; n = 279) and 2 patient samples (patients with rheumatoid arthritis, n = 121; patients with atopic dermatitis, n = 70). We evaluated the psychometric properties of the GAMQ by determining the factor structure and its stability across samples, internal consistency, and convergent validity.

RESULTS

The GAMQ contains 6 positive and 6 negatively worded items. A factor structure was observed with three subscales, representing 'Trust in medication', 'Concerns about medication', and 'Reluctance to use medication'. The fit of the factor structure was satisfactory across samples, considering classic cut-offs, with an adequate or close to adequate fit. The total scale showed good internal consistency, good convergent validity with related scales (i.e., Beliefs about Medicines Questionnaire - General and a single medication attitude scale), and concurrent validity as reflected in associations with expectations about pain- and itch-relieving medication. It was not consistently or strongly associated with demographic or health-related characteristics.

CONCLUSIONS

The newly developed GAMQ showed satisfactory psychometric properties in a variety of populations, although limitations should be considered. The GAMQ is the first scale to assess both positive and negative attitudes towards medication in general, providing indicators of Trust, Concerns, and Reluctance regarding medication. The scale may be an informative measure for predicting treatment outcomes and adherence, as well as placebo and nocebo effects in diverse samples.

The Power of a Good Word: Enhancing the Efficacy of Analgesics in Clinical Settings

INTRODUCTION

Communication between medical staff and patients about treatment efficacy elicits expectations of benefit and improves treatment outcomes. While demonstrated in multiple studies via different research methodologies, uniform communication protocols have not been adopted in clinical practice. Here, we summarize the results of two sister studies aimed at bridging this gap.

METHODS

Women undergoing C-section (study 1, randomized controlled trial) and patients undergoing general or otolaryngologic surgeries (study 2, control group design) were recruited and assigned to the "regular communication" (RC) or "enhanced communication" (EC) arms. The EC arm received positive information about treatment, while the RC arm received no such information. In both studies, the primary outcome was change in pain intensity; in study 2, an additional outcome was morphine consumption.

RESULTS

Eighty women successfully completed study 1, and 102 patients successfully completed study 2. In both studies, significant time*group interactions were observed (p < 0.001). The analgesic effect was virtually twice as large in the EC arm compared to the RC arm. In study 2, in the last two timepoints of assessment, participants in the EC arm also consumed fewer doses of opioids than participants in the RC arm (p < 0.001). No significant differences were found in vital signs.

CONCLUSIONS

We provide ecological evidence that positive information about treatment significantly decreases pain and opioid consumption during routine clinical care. This study and others could encourage healthcare providers to harness the powerful effects of patients' expectations of benefit to improve analgesics outcomes and, potentially, the outcomes of other symptoms.

INTRODUCTION

Communication between medical staff and patients about treatment efficacy elicits expectations of benefit and improves treatment outcomes. While demonstrated in multiple studies via different research methodologies, uniform communication protocols have not been adopted in clinical practice. Here, we summarize the results of two sister studies aimed at bridging this gap.

METHODS

Women undergoing C-section (study 1, randomized controlled trial) and patients undergoing general or otolaryngologic surgeries (study 2, control group design) were recruited and assigned to the "regular communication" (RC) or "enhanced communication" (EC) arms. The EC arm received positive information about treatment, while the RC arm received no such information. In both studies, the primary outcome was change in pain intensity; in study 2, an additional outcome was morphine consumption.

RESULTS

Eighty women successfully completed study 1, and 102 patients successfully completed study 2. In both studies, significant time*group interactions were observed (p < 0.001). The analgesic effect was virtually twice as large in the EC arm compared to the RC arm. In study 2, in the last two timepoints of assessment, participants in the EC arm also consumed fewer doses of opioids than participants in the RC arm (p < 0.001). No significant differences were found in vital signs.

CONCLUSIONS

We provide ecological evidence that positive information about treatment significantly decreases pain and opioid consumption during routine clinical care. This study and others could encourage healthcare providers to harness the powerful effects of patients' expectations of benefit to improve analgesics outcomes and, potentially, the outcomes of other symptoms.

How can imaginal retraining for modifying food craving be improved?

Imaginal retraining (IR) is an emerging intervention technique in which people imagine avoidance behaviors towards imagined foods or other substances, such as throwing them away. Although IR shows promise in reducing initial craving for a range of substances, including alcohol and tobacco, effects appear less robust for craving for energy-dense foods. This raises the question of how IR for food craving can be improved. Here, we address this question informed by emerging findings from IR dismantling studies and the field of regular cognitive bias modification training paradigms. Based on current insights, we suggest the most optimal 'craving-reduction' effects for energy-dense food can likely be expected for IR that includes an overt motor movement. While it is not yet clear what movement works best for food, we suggest a tailored movement or Go/No-Go-based stop movement has the potential to be most effective. The most likely mechanism in reducing craving is cue-devaluation of trained vivid craving images regarding specific energy-dense food products. Future work is needed that investigates and assess the underlying mechanisms (e.g., updating beliefs; cue-devaluation), task characteristics (e.g., IR instructions; specific motor movements) and individual characteristics (e.g., perceived craving; vividness of food imagination) that determine IR effects.

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

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

Assessment of treatment expectations in people with suspected endometriosis: A psychometric analysis

Background

Treatment expectations influence clinical outcomes in various physical and psychological conditions; however, no studies have explored their role in endometriosis treatment. It is necessary to understand how these expectations can be measured to study treatment expectations and their effects in clinical practice. This study aimed to psychometrically analyze and compare different treatment expectation measurements and describe treatment expectations in women with suspected endometriosis.

Method

Analysis of cross-sectional baseline data of a mixed-method clinical observational study of N=699 patients undergoing laparoscopy in Germany. Descriptives, bivariate associations, convergent and discriminant validity of four expectation measurements (Treatment Expectation Questionnaire (TEX-Q); Generic rating scale for previous treatment experiences, treatment expectations, and treatment effects (GEEE); numerical rating scales (NRS) assessing improvement and worsening of endometriosis symptoms, expected Pain Disability Index (PDI); range: 0 to 10) were estimated. A cluster analysis was performed on the three GEEE items.

Results

Most participants expected high improvement ( M=6.68 to 7.20, SD=1.90 to 2.09) and low worsening ( M=1.09 to 2.52, SD=1.80 to 2.25) of disability from laparoscopy. Participants who expected greater worsening expected more side effects ( r=.31 to .60, p<.001). Associations between the positive and negative expectation dimensions, including side effects, were small to non-significant ( r =|.24| to .00, p<.001 to.978). Four distinct clusters, described as'positive', 'no pain, no gain', 'diminished', and 'uniform' were found, with a total PVE of 62.2%.

Conclusions

Women with suspected endometriosis reported positive expectations concerning laparoscopy, but wide ranges indicated interindividual differences. Treatment expectations seem to be a multidimensional construct in this patient group. The investigated measurements did not correlate to the extent that they measured exactly the same construct. The selection of measurements should be carefully considered and adapted for the study purposes. Clusters provide initial indications for individualized interventions that target expectation manipulation.

Trial Registration Number

ID NCT05019612 ( ClinicalTrials.gov).

Conclusions Regarding the Role of Expectations in Placebo Analgesia Studies May Depend on How We Investigate It: A Meta-Analysis, Systematic Review, and Proposal for Methodological Discussions

OBJECTIVE

Expectations are highlighted as a key component in placebo effects. However, there are different approaches to whether and how placebo studies should account for expectations, and the direct contribution has yet to be estimated in meta-analyses. Using different methodological approaches, this meta-analysis and systematic review examines the extent to which expectations contribute to pain in placebo studies.

METHODS

The databases PubMed, PsycINFO, Embase, and Web of Science were searched for placebo analgesia mechanism studies with numerical measures of both expectations and pain. Thirty-one studies, comprising 34 independent study populations (1566 subjects: patients and healthy participants) were included. Two meta-analyses were conducted: meta-analysis 1, using study-level data, estimated the effect of expectation interventions without taking measures of expectations into account (expectations assumed); and meta-analysis 2, using individual-level data, estimated the direct impact of participants' expectations on pain (expectations assessed). Risk of bias was assessed using the Cochrane risk-of-bias tool.

RESULTS

Meta-analysis 1 showed a moderate effect of expectation interventions over no expectation intervention on pain intensity (Hedges g = 0.45, I2 = 54.19). Based on 10 studies providing individual-level data, meta-analysis 2 showed that expectations predicted pain intensity in placebo and control groups ( b = 0.36, SE = 0.05), although inconsistently across study methodologies.

CONCLUSIONS

Participants' expectations contributed moderately to pain in placebo analgesia studies. However, this may largely be influenced by how we measure expectations and how their contribution is conceptualized and analyzed-both within and across studies.

Mindfulness Effects on Anxiety: Disentangling the Role of Decentering and Treatment Expectations

Mindfulness interventions have been found to lower anxiety. However, the current literature has not adequately considered the role of its individual components and of placebo effects. In an online experiment using a balanced placebo design, we aimed to disentangle effects of decentering, a key component of mindfulness, and expectations, a key component of placebo effects, on anxiety related to the COVID-19 pandemic. One hundred twenty-eight adults were randomly assigned to one of four groups: placebo/mindful decentering, placebo/sham decentering, sham/mindful decentering, and sham/sham decentering. Instructions were provided using standardized audio instructions. Current anxiety was assessed pre- and postintervention with the Short State version of the State-Trait Anxiety Inventory. Mindful decentering was found to reduce anxiety postintervention, as compared to sham decentering, regardless of induced expectations regarding its effectiveness. Participants in the mindful decentering group also mentioned more decentering-related words than those in the sham decentering group. These findings indicate that a short, standardized, and online mindful decentering intervention can effectively decrease pandemic-related anxiety independently of one's expectations. These findings provide insights into the efficacy of the individual elements of mindfulness, highlighting decentering as an effective active component for anxiety relief. Moreover, these findings suggest that, in a nonclinical sample, individuals can apply mindful decentering with minimal training.

The development of an implicit measure of treatment expectations

In three preregistered studies, we investigated whether implicit treatment expectations, using a relational implicit measure (the MT-PEP), vary between participants provided opposing information about novel medical treatments (Studies 1 and 2) or who responded based on normative beliefs toward common over-the-counter drugs (Study 3). The studies revealed large Cohen's d effect sizes of both novel and well-known treatment information within the implicit measure. The studies also provide evidence of convergent validity, with MT-PEP scores associated with explicit beliefs about medicine and over-the-counter drug familiarity. Implicit treatment expectations can be assessed and offer a novel tool for the intersection of social psychology and medicine.

Can observational learning reinforce open-label placebo hypoalgesia?

ABSTRACT

Previous research has indicated that an open-label placebo can reduce pain in both healthy participants and patients with chronic pain. Because nondeceptive placebos seem to be an effective and more ethical alternative to deceptive placebos, optimizing this kind of treatment is essential. Observational learning was previously shown to induce the deceptive placebo effect; therefore, this study aimed to verify its effectiveness in fortifying the open-label placebo effect. Healthy volunteers (N = 117) were randomly assigned to 4 groups: open-label placebo with observational learning (OLP + OBL), open-label placebo (OLP), deceptive placebo with observational learning (OBL), or control group. Participants underwent baseline and testing measurements, during which they self-reported pain induced by heat stimulation. Between assessments, placebo cream was openly administered in the OLP and OLP + OBL groups. The OLP + OBL group next watched a model experiencing hypoalgesia after cream application. In the OBL group, participants received placebo cream with no information about its effect, and then they watched the model. The placebo effect was successfully evoked in all experimental groups (OLP + OBL, OLP, and OBL), which confirms the effectiveness of both open-label and deceptive placebo interventions for pain reduction. However, the hypoalgesic effect was of similar magnitude in the OLP and OLP + OBL groups, which indicates that observation did not contribute to the effect. The results showed that reinforcing the open-label placebo by observational learning may be redundant, but more research is needed to confirm these findings.

Change in pain expectations but no open-label placebo analgesia: An experimental study using the heat pain paradigm

BACKGROUND

Open-label placebos (OLP) prescribed without deception and with a convincing rationale have been shown to evoke powerful treatment effects. Patients' treatment expectations seem to influence the magnitude of the effect.

OBJECTIVE

We examined if two different OLP rationales increased pain tolerance and reduced pain intensity and unpleasantness in a standardized heat pain experiment.

METHODS

Participants (N = 71) who self-reported reoccurring pain for at least the last 3 months were randomly assigned to one of three groups. We compared a personal-emotional and a scientific-matter-of-fact rationale with a control group (CG) that received the same placebo without any rationale. The rationale suggested a desensitizing effect on pain perception and improved pain coping of the placebo, whereas in the CG it was introduced as an ointment for measurement. The primary outcomes were pre-post changes in pain tolerance, expected and experienced pain intensity and unpleasantness.

RESULTS

Participants showed a decrease in expected pain intensity, but not expected pain unpleasantness for both rationales. There were no differences in pain tolerance and experienced pain intensity and unpleasantness.

CONCLUSIONS

Our study suggests that evoking positive treatment expectations is not sufficient to elicit an OLP response. Possibly, the magnitude of expectations change in this study was not powerful enough to evoke an OLP effect. Additionally, it is possible that OLP effects in pain are unrelated to positive treatment expectations. The failure of OLP in our study is in contrast to a number of previous studies examining the effects of OLP in experimental and clinical pain.

SIGNIFICANCE

This study provides evidence that positive treatment expectations are not sufficient to evoke an open-label placebo effect in a standardized heat pain experiment. We showed that two different rationales improved participants treatment expectations, but failed to evoke a placebo effect in comparison to a control group that received the same placebo, labelled as an ointment to improve measurement quality.

Veteran Beliefs About the Causes of Gulf War Illness and Expectations for Improvement

BACKGROUND

Individuals' beliefs about the etiology of persistent physical symptoms (PPS) are linked to differences in coping style. However, it is unclear which attributions are related to greater expectations for improvement.

METHOD AND RESULTS

A cross-sectional regression analysis (N = 262) indicated that Veterans with Gulf War Illness (GWI) who attributed their GWI to behavior, (e.g., diet and exercise), had greater expectations for improvement (p = .001) than those who attributed their GWI to deployment, physical, or psychological causes (p values > .05).

CONCLUSIONS

Findings support the possible clinical utility of exploring perceived contributing factors of PPS, which may increase perceptions that improvement of PPS is possible.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02161133.

A single-item Expectancy Measure's Validity, Reliability, and Responsiveness to Detect Changes in Clinical Efficacy Studies of Integrative Cancer Therapies: A Methodology Study

BACKGROUND

Expectations may modify outcomes. However, studies often fail to measure expectations. This raises the need for a brief valid and reliable expectancy measure.

OBJECTIVES

To study treatment expectations in individuals entering acupuncture or rest, validity and test re-test reliability of a single-item expectancy measure graded on a category scale, a Numeric Rating Scale (NRS) and a Visual Analog Scale (VAS), and to identify psychometric differences between the scales.

METHOD

In this methodology study, treatment expectations were measured in 363 participants before they received acupuncture (genuine traditional penetrating or non-penetrating telescopic sham acupuncture, n = 239, 98%, responded) or a control treatment involving just rest (n = 120, 100%, responded), aimed to improve level of relaxation. A treatment expectancy measure, graded on a five-grade category scale, an eight-grade NRS and a 100 mm VAS, was tested for test re-test reliability. Level of expectation and relaxation was measured at baseline, pre- and post-therapy (n = 729 expectancy measurements).

RESULTS

The participants scheduled for acupuncture or rest believed moderately (Inter Quartile Range, IQR, moderately-much) and much (IQR moderately-much) the treatment to be effective. The Intra-Class Correlation coefficient versus Kappa coefficient between test and re-test was .868/.868 for the category scale, .820/.820 for the NRS, and .856/.854 for the VAS. The middle step "Believe moderately the treatment to be effective" was equivalent with median 4 (IQR, 3-4) on NRS and median 52 mm (IQR 42-52) on VAS. The response rates were 708 (97%) on the category scale, 707 (97%) on the NRS, and 703 (96%) on the VAS. All three scales discriminated that pre-therapy expectations were more positive in the individuals who reported an improvement in relaxation level (P < .001-.003). The VAS presented higher responsiveness to detect expectancy changes over time (71% increased expectation), compared to the NRS (52% increased) and the category scale (12% increased), P < .001.

CONCLUSIONS

Individuals entering acupuncture, or a control intervention, presented positive treatment expectations, and the expectancy measure presented satisfactory reliability, validity, high response rates, sensitiveness, and responsiveness. Integrative cancer therapy researchers who want to control for expectancy-related bias in clinical trials should consider measuring expectation using the single-item expectancy measure.

Suggestion Timing Moderates the Effects of Prior Pain Experiences on Pain Perception

Two common elements in patient care are reoccurring painful events (eg, blood draws) and verbal suggestions from others for lessened pain. Research shows that verbal suggestions for lower pain can decrease subsequent pain perception from novel noxious stimuli, but it is less clear how these suggestions and prior painful experiences combine to influence the perception of a reoccurring painful event. The presented experiment tested the hypothesis that the order of these 2 factors influence pain perception for a reoccurring painful event. All participants (702 healthy college-student volunteers, 58% women, 85.5% White) experienced a novel painful event on one arm, then again on their other arm (now a familiar pain event). Participants who received the suggestion that they can tolerate more pain on the second arm relative to the first from the outset, before the initial pain event, perceived relatively less pain during the repeated event as compared to participants who received the same suggestion after the first painful event or no-suggestion (control). Given many pain events within medical contexts are, or become, familiar to patients, further researching the timing at which patients receive verbal suggestions for lower pain can inform practices to optimize the therapeutic, pain-reducing potential of such suggestions. PERSPECTIVE: Providing suggestions that a familiar pain event (ie, the second of 2) will be less painful than a prior event can reduce perceived pain for the familiar event depending on when it is presented. These findings can inform practices to optimize the therapeutic potential of verbal suggestions for reduced pain.

The Optimal Learning Cocktail for Placebo Analgesia: A Randomized Controlled Trial Comparing Individual and Combined Techniques

This study investigated for the first time the effects of individual and combined application of 3 learning techniques (verbal suggestions, classical conditioning, and observational learning) on placebo analgesia and extinction. Healthy participants (N = 206) were assigned to 8 different groups in which they were taught through either a verbal suggestion, a conditioning paradigm, a video observing someone, or any combination thereof that a placebo device (inactive transcutaneous electric nerve stimulation [TENS]) was capable of alleviating heat pain, whereas one group did not (control). Placebo analgesia was quantified as the within-group difference in experienced pain when the placebo device was (sham) 'activated' or 'inactivated' during equal pain stimuli, and compared between groups. Placebo analgesia was induced in groups with 2 or 3 learning techniques. Significantly stronger placebo analgesia was induced in the combination of all 3 learning techniques as compared to the individual learning techniques or control condition, underlining the additional contribution of 3 combined techniques. Extinction did not differ between groups. Furthermore, pain expectancies, but not state anxiety or trust, mediated placebo analgesia. Our findings emphasize the added value of combining 3 learning techniques to optimally shape expectancies that lead to placebo analgesia, which can be used in experimental and clinical settings. PERSPECTIVE: This unique experimental study compared the individual versus combined effects of 3 important ways of learning (verbal suggestions, classical conditioning, and observational learning) on expectation-based pain relief. The findings indicate that placebo effects occurring in clinical practice could be optimally strengthened if healthcare providers apply these techniques in combination.

Is Positive Communication Sufficient to Modulate Procedural Pain and Anxiety in the Emergency Department? A Randomized Controlled Trial

OBJECTIVE

Research suggests that therapeutic communication could enhance patient comfort during medical procedures. Few studies have been conducted in clinical settings, with adequate blinding. Our hypothesis was that a positive message could lead to analgesia and anxiolysis, and that this effect would be enhanced by an empathetic interaction with the nurse performing the procedure, compared with an audio-taped message. This study aimed to modulate the contents and delivery vector of a message regarding peripheral intravenous catheter (PIC) placement in the emergency department (ED).

METHODS

This study was a 2 + 2 randomized controlled trial registered on ClinicalTrials.gov (NCT03502655). A positive versus standard message was delivered through audio tape (double-blind) in the first phase ( N = 131) and through the nurse placing the catheter (single-blind) in the second phase ( N = 120).

RESULTS

By design, low practitioner empathic behavior was observed in the first phase (median, 1 of 5 points). In the second phase, higher empathic behavior was observed in the positive than in the standard message (median, 2 versus 3, p < .001). Contrary to our hypothesis, the intervention did not affect pain or anxiety reports due to PIC placement in either phase (all p values > .2).

CONCLUSIONS

The positive communication intervention did not impact pain or anxiety reports after PIC. There might have been a floor effect, with low PIC pain ratings in a context of moderate pain due to the presenting condition. Hence, such a therapeutic communication intervention might not be sufficient to modulate a mild procedural pain in the ED.

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.

Nocebo effects in visceral pain: concept and design of the experimental randomized-controlled pain study 'NoVis'

The role of psychological factors in the pathophysiology and treatment of chronic visceral pain in disorders of gut-brain interactions (DGBI) is increasingly appreciated. Placebo research has underscored that expectations arising from the psychosocial treatment context and from prior experiences shape treatment responses. However, effects of negative expectations, i.e., nocebo effects, as they are likely crucial elements of DGBI patients' clinical reality, have thus far only rarely been investigated in the context of visceral pain, with untapped potential for improved prevention and treatment. The experimental randomized-controlled pain study "NoVis," carried out within the Collaborative Research Center (CRC) 289 ("Treatment Expectation"), aims to close gaps regarding the generation and persistence of nocebo effects in healthy volunteers. It is designed to elucidate effects of negative expectations in a multiple-threat paradigm with intensity-matched rectal distensions and cutaneous thermal stimuli, allowing to test nocebo effects in the visceral and somatic pain modalities. Negative expectations are experimentally induced by elements of doctor-patient communication (i.e., instruction) and/or by surreptitious amplification of symptom intensity (i.e., experience/learning) within a treatment context. Accordingly, the repeated measures between-subject design contains the between-group factors "treatment instruction" (negative vs. control) and "treatment experience" (negative vs. control), with volunteers randomized into four experimental groups undergoing several pain stimulation phases (repeated factor). This allows to compare the efficacy of instruction vs. experience, and more importantly, their combined effects on the magnitude of negative expectations and their impact on pain responses, which we expect will be greatest for the visceral modality. After a Baseline, short-term effects are assessed during a test phase accomplished on study day 1 (Test-1 Phase). To explore the persistence of effects, a second test phase is accomplished 1 week later (Test-2 Phase). Effects of negative expectations within and across pain modalities are assessed at the subjective and objective levels, with a focus on psychophysiological and neuroendocrine measures related to stress, fear, and anxiety. Since nocebo effects can play a considerable role in the generation, maintenance, or worsening of chronic visceral pain, and may even constitute risk factors for treatment failure, knowledge from experimental nocebo research has potential to improve treatment outcomes in DGBI and other clinical conditions associated with chronic visceral pain.

Cross-Cultural Adaptation and Measurement Properties of the Expectations for Treatment Scale (ETS) for Greek-Speaking Patients

Introduction Patients' treatment expectations are key factors influencing the health outcomes in various medical conditions. Using validated measures to capture these expectations has been strongly suggested to improve the prognosis of the health outcome and promote research investigations. The Expectations for Treatment Scale (ETS) is a well-established questionnaire designed to accurately measure treatment expectations in patients with low back pain; however, it is not available in Greek yet. We aimed to translate and cross-culturally adapt the ETS in Greek (ETS-Gr) and evaluate its reliability and validity in a Greek-speaking population with musculoskeletal disorders. Methods We followed published recommendations for the translation and cross-cultural adaptation process of the scale. Face and content validity were evaluated using interviews with patients and experts. Internal consistency, test-retest reliability, and measurement error were evaluated in 52 patients with musculoskeletal conditions. Results During forward and backward translation minor linguistic discrepancies were detected and effectively adapted for Greek-speaking patients. The ETS-Gr presented a high level of content validity (item content validity index: 0.88-1; and average scale content validity index: 0.90), acceptable internal consistency (Cronbach's alpha: 0.84), and excellent test-retest reliability (intraclass correlation coefficient: 0.96, 95% confidence interval: 0.93-0.98). Conclusions The ETS-Gr is a short, reliable, and valid instrument to measure pre-treatment expectations in patients with musculoskeletal disorders. Future investigations including other medical conditions are required.

How Instructions, Learning, and Expectations Shape Pain and Neurobiological Responses

Treatment outcomes are strongly influenced by expectations, as evidenced by the placebo effect. Meta-analyses of clinical trials reveal that placebo effects are strongest in pain, indicating that psychosocial factors directly influence pain. In this review, I focus on the neural and psychological mechanisms by which instructions, learning, and expectations shape subjective pain. I address new experimental designs that help researchers tease apart the impact of these distinct processes and evaluate the evidence regarding the neural mechanisms by which these cognitive factors shape subjective pain. Studies reveal that expectations modulate pain through parallel circuits that include both pain-specific and domain-general circuits such as those involved in affect and learning. I then review how expectations, learning, and verbal instructions impact clinical outcomes, including placebo analgesia and responses to pharmacological treatments, and discuss implications for future work.

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.

Placebo effects on cutaneous pain and itch: a systematic review and meta-analysis of experimental results and methodology

ABSTRACT

Placebo effects, positive treatment outcomes that go beyond treatment processes, can alter sensations through learning mechanisms. Understanding how methodological factors contribute to the magnitude of placebo effects will help define the mechanisms by which these effects occur. We conducted a systematic review and meta-analysis of experimental placebo studies in cutaneous pain and itch in healthy samples, focused on how differences in methodology contribute to the resulting placebo effect magnitude. We conducted meta-analyses by learning mechanism and sensation, namely, for classical conditioning with verbal suggestion, verbal suggestion alone, and observational learning, separately for pain and itch. We conducted subgroup analyses and meta-regression on the type of sensory stimuli, placebo treatment, number of acquisition and evocation trials, differences in calibrated intensities for placebo and control stimuli during acquisition, age, and sex. We replicated findings showing that a combination of classical conditioning with verbal suggestion induced larger placebo effects on pain ( k = 68, g = 0 . 59) than verbal suggestion alone ( k = 39, g = 0.38) and found a smaller effect for itch with verbal suggestion alone ( k = 7, g = 0.14). Using sham electrodes as placebo treatments corresponded with larger placebo effects on pain than when topical gels were used. Other methodological and demographic factors did not significantly affect placebo magnitudes. Placebo effects on pain and itch reliably occur in experimental settings with varied methods, and conditioning with verbal suggestion produced the strongest effects. Although methods may shape the placebo effect to some extent, these effects appear robust overall, and their underlying learning mechanisms may be harnessed for applications outside the laboratory.

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.

A new paradigm for musculoskeletal pain care: moving beyond structural impairments. Conclusion of a chiropractic and manual therapies thematic series

This commentary closes the thematic series "A new paradigm for musculoskeletal pain care: moving beyond structural impairments". The papers published in the series point to key aspects of shifting the paradigm of musculoskeletal care from clinician-led management often focused on addressing presumed structural anomalies to partnering with patients to find individual strategies that empower patients towards self-management. Several papers in the series highlighted the need for developing patient-centred models of care that respect individual patient's needs and preferences. Also, the series pointed to different options for modes of delivery including mHealth and the challenges and opportunities they present for developing person-centred strategies. For health care to provide effective support for people with musculoskeletal pain conditions, there is a need to recognise that contextual factors, including a strong patient-provider alliance, clearly play an important, perhaps primary, role. Health care professions dealing with musculoskeletal pain conditions should engage in research to investigate effective ways to move this understanding into practice including how to train providers. We hope the work collected in this series will stimulate further questions and more research as musculoskeletal pain providers seek to make their care more person-centred.

Treatment Invasiveness and Illness Perceptions Are Strongly Associated With Outcome Expectations in Patients Treated for Hand or Wrist Conditions: A Cross-sectional Study

BACKGROUND

Multiple studies have shown that more-positive outcome expectations are associated with better treatment outcomes. Although this has not been shown to represent a causal relationship, there nonetheless is an interest in positively modifying outcome expectations to improve treatment outcomes. However, little is known about what is independently associated with outcome expectations in clinical practice. For example, it is unknown to what extent expectations are associated with treatment or patient characteristics such as sociodemographics or with patient-reported outcome measures (PROMs) on patient perceptions of physical or mental health or illness. Studying factors associated with outcome expectations may provide relevant information for clinicians and researchers aiming to improve outcome expectations. Improving expectations might, in turn, improve treatment outcomes.

QUESTION/PURPOSE

Which factors (that is, sociodemographics, PROMs, illness perceptions, treatment, surgeon, and location) are independently associated with outcome expectations in patients with hand or wrist conditions?

METHODS

This was a cross-sectional study. Between July 2018 and December 2021, we screened 21,327 patients with a diagnosed hand or wrist condition with complete baseline sociodemographic data such as age and workload. Sixty percent (12,765 of 21,327) of patients completed all relevant PROMs. We excluded patients receiving rare treatments, leaving 58% (12,345 of 21,327) for inclusion in the final sample. Those who participated were more often scheduled for surgical treatment and had higher expectations. We performed a multilevel analysis involving two steps. First, we evaluated whether patients receiving the same treatment, being counseled by the same surgeon, or being treated at the same location have more similar outcome expectations. We found that only patients receiving the same treatment had more similar outcome expectations. Therefore, we used a multilevel regression model to account for this correlation within treatments, and added treatment characteristics (such as nonsurgical versus minor or major surgery) to potential explanatory factors. Second, in the multilevel hierarchical regression analysis, we added sociodemographics (Model 1), PROMs for physical and mental health (Model 2), illness perceptions (Model 3), and treatment characteristics (most-definitive model) to assess the explained variance in outcome expectations per step and the relative association with outcome expectations.

RESULTS

Sociodemographic factors such as age and workload explained 1% of the variance in outcome expectations. An additional 2% was explained by baseline PROMs for physical and mental health, 9% by illness perceptions, and 18% by treatment characteristics, resulting in an explained variance of 29% of the most-definitive model. A large number of patient and treatment characteristics were associated with outcome expectations. We used standardized betas to compare the magnitude of the effect of the different continuous and categorical variables. Among the associated variables, minor surgery (standardized beta [β] = 0.56 [95% confidence interval 0.44 to 0.68]; p < 0.001) and major surgery (β = 0.61 [95% CI 0.49 to 0.73]; p < 0.001) had the strongest positive association with outcome expectations (receiving surgery is associated with higher outcome expectations than nonsurgical treatment). A longer illness duration expected by the patient (-0.23 [95% CI -0.24 to -0.21]; p < 0.001) and being treated for the same condition as before (-0.08 [95% CI -0.14 to -0.03]; p = 0.003) had the strongest negative association with outcome expectations.

CONCLUSION

Outcome expectations are mainly associated with the invasiveness of the treatment and by patients' illness perceptions; patients before surgical treatment have more positive expectations of the treatment outcome than patients before nonsurgical treatment, even after accounting for differences in clinical and psychosocial profiles. In addition, patients with a more-positive perception of their illness had more-positive expectations of their treatment. Our findings suggest expectation management should be tailored to the specific treatment (such as surgical versus nonsurgical) and the specific patient (including their perception of their illness). It may be more beneficial to test and implement expectation management strategies for nonsurgical treatments such as physical therapy than for surgical treatments, given that our findings indicate a greater need to do so. An additional advantage of such a strategy is that successful interventions may prevent converting to surgical interventions, which is a goal of the stepped-care principles of standard care. Future studies might investigate the causality of the association between pretreatment expectations and outcomes by performing an experimental study such as a randomized controlled trial, in which boosting expectations is compared with usual care in nonsurgical and surgical groups.

LEVEL OF EVIDENCE

Level III, prognostic study.

Learned Nocebo Effects on Cutaneous Sensations of Pain and Itch: A Systematic Review and Meta-analysis of Experimental Behavioral Studies on Healthy Humans

OBJECTIVE

In past decades, the field of nocebo research has focused on studying how sensory perception can be shaped by learning. Nocebo effects refer to aggravated sensory experiences or increased sensitivity to sensations such as pain and itch resulting from treatment-related negative experiences. Behavioral conditioning and verbal suggestions of a negative treatment outcome may aggravate pain and itch perception. Gaining a comprehensive view of the magnitude of nocebo effects and contributing factors will help steer nocebo research toward fruitful directions for understanding complex sensory phenomena.

METHODS

We conducted a systematic review and meta-analysis of a total of 37 distinct experimental nocebo studies on healthy participants (all published in English between 2008 and 2021), with four separate meta-analyses for nocebo effects on pain or itch. We conducted subgroup analyses and meta-regression on factors such as type and intensity of sensory stimuli, and length of conditioning paradigms.

RESULTS

This meta-analysis showed that, on average, effect sizes of nocebo effects were moderate to large (Hedges g between 0.26 and 0.71 for the four primary outcomes). The combination of conditioning and verbal suggestions yielded stronger nocebo responses on pain in particular. Subgroup analyses, including factors such as the type of sensory stimulation, did not explain the moderate heterogeneity in nocebo magnitudes between different studies. Risk of bias was generally low and was not related to nocebo magnitudes either.

CONCLUSIONS

We discuss these results in relation to the role of conditioning and aversive learning, and we recommend more consistency in designing and reporting nocebo experiments.

Local brain oscillations and interregional connectivity differentially serve sensory and expectation effects on pain

Pain emerges from the integration of sensory information about threats and contextual information such as an individual's expectations. However, how sensory and contextual effects on pain are served by the brain is not fully understood so far. To address this question, we applied brief painful stimuli to 40 healthy human participants and independently varied stimulus intensity and expectations. Concurrently, we recorded electroencephalography. We assessed local oscillatory brain activity and interregional functional connectivity in a network of six brain regions playing key roles in the processing of pain. We found that sensory information predominantly influenced local brain oscillations. In contrast, expectations exclusively influenced interregional connectivity. Specifically, expectations altered connectivity at alpha (8 to 12 hertz) frequencies from prefrontal to somatosensory cortex. Moreover, discrepancies between sensory information and expectations, i.e., prediction errors, influenced connectivity at gamma (60 to 100 hertz) frequencies. These findings reveal how fundamentally different brain mechanisms serve sensory and contextual effects on pain.

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.

Expectations affect pain sensitivity changes during massage

BACKGROUND

Pain-inducing massage produces comparable changes in pain sensitivity as a cold pressor task, suggesting shared neurophysiological mechanisms of conditioned pain modulation. Manual therapy and conditioned pain modulation are influenced by positive and negative expectations. Therefore, the purpose of this study was to examine the effects of positive and negative expectations on pain-free and pain-inducing massage.

METHODS

56 healthy participants were randomly assigned to receive a positive or negative expectation instructional set followed by a pain-inducing or a pain-free massage. Pressure pain threshold (PPT) was measured followed by each interval of massage. A repeated measures ANCOVA controlling for post-randomization differences in sex tested for massage x expectation set x PPT interaction effects, as well as two-way interaction effects.

RESULTS

A significant three-way interaction effect (p = 0.04) and time x expectation interaction effect was observed for individuals receiving pain inducing massage (p = 0.02). Individuals who received the positive expectation instructional set demonstrated significantly higher PPT at minutes 3 and 4 of massage compared to individuals who received the negative expectation instructional set.

CONCLUSIONS

Expectations impact pain sensitivity changes produced during massage. Clinicians planning to provide pain-inducing massage should consider the role of expectations in modulating pain sensitivity changes.

Blinding and sham control methods in trials of physical, psychological, and self-management interventions for pain (article II): a meta-analysis relating methods to trial results

ABSTRACT

Sham interventions in randomized clinical trials (RCTs) of physical, psychological, and self-management (PPS) therapies for pain are highly variable in design and believed to contribute to poor internal validity. However, it has not been formally tested whether the extent to which sham controls resemble the treatment under investigation consistently affects trial outcomes, such as effect sizes, differential attrition, participant expectancy, and blinding effectiveness. Placebo- or sham-controlled RCTs of PPS interventions of clinical pain populations were searched in 12 databases. The similarity of control interventions to the experimental treatment was rated across 25 features. Meta-regression analyses assessed putative links between employed control interventions, observed effect sizes in pain-related outcomes, attrition, and blinding success. The sample included 198 unique control interventions, dominated by manual therapy and chronic musculoskeletal pain research. Meta-analyses indicated small-to-moderate benefits of active treatments over control interventions, across subgroups of manual therapies, exercise, and rehabilitation, and psychological intervention trials. Multiple meta-regression modelling demonstrated that similarity between sham control and tested interventions predicted variability in pain-related outcomes, attrition, and blinding effectiveness. Influential variables were differences relating to the extent of intervention exposure, participant experience, and treatment environments. The results support the supposed link between blinding methods and effect sizes, based on a large and systematically sourced overview of methods. However, challenges to effective blinding are complex and often difficult to discern from trial reports. Nonetheless, these insights have the potential to change trial design, conduct, and reporting and will inform guideline development.

Association between personality traits and placebo effects: a preregistered systematic review and meta-analysis

ABSTRACT

Placebo effects are ubiquitous yet highly variable between individuals and therefore strongly affect clinical trial outcomes such as pain relief. It is unclear whether dispositional psychological traits influence responsiveness to placebo. This preregistered meta-analysis and systematic review synthesized the literature investigating the association between personality traits and placebo effects. Based on 21 studies with 798 participants, we performed formal meta-analyses for 10 different personality traits, including behavioral inhibition, fun seeking, goal-drive persistence, reward responsiveness, empathic concern, empathic fantasy, perspective-taking, personal distress, optimism, and anxiety. We did not find evidence of associations between any of these traits and magnitude of placebo effects, which was supported by equivalence tests. Furthermore, we did not find evidence for moderating factors such as placebo manipulation type (conditioning or nonconditioning) or condition (pain or nonpain). These findings challenge the notion that personality influences responsiveness to placebos and contradict its utility for identifying placebo "responders" and "nonresponders."

The effect of preconditioning on the modalities of pain management

OBJECTIVES

This study investigated the effect of positive preconditioning on the specific modality of verbal and touch interventions, in pain management.

METHODS

We compared pain ratings in 51 participants who underwent a cold pressor test twice (T1, T2). The results from the first test were used as a reference. For the second test, the participants were divided into 5 groups. Four groups received verbal or touch intervention during the test, with or without preconditioning. The fifth group was a control group. We compared dVAS (pain ratings at T1 minus T2) between groups to assess the effect of the interventions and the preconditioning. We also explored the within-group association between dVAS and pain-related traits.

RESULTS

We found a significant effect of preconditioning on dVAS. The post hoc test showed that the preconditioned verbal group reported higher dVAS than the non-preconditioned one. Participants' emotional awareness scores were negatively correlated with dVAS in the preconditioned touch group.

CONCLUSION

These data suggested that preconditioning enhances pain management, regardless of intervention modalities. However, the preconditioning effect for the touch modality was negatively associated with the participants' emotional awareness.

PRACTICE IMPLICATIONS

Communication must be adapted with caution, depending on the treatment and the patients' emotional status.

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.

Acute and subacute postsurgical pain in women with breast cancer: incidence and associations with biopsychosocial predictors-a secondary analysis of a randomized controlled trial

Introduction

Women who undergo breast cancer surgery risk suffering from postsurgical pain long after their surgery. Still, research on postsurgical pain in the subacute phase has been neglected.

Objective

This study aims to investigate the incidence, intensity, unpleasantness, and presurgical predictors of acute and subacute postsurgical pain after breast cancer surgery.

Methods

The study used an observational design through secondary analyses of the control group in a randomized controlled trial. Data from 102 women undergoing breast cancer surgery were included. Levels of acute and subacute pain intensity and unpleasantness were measured using 100 mm Visual Analogue Scales on the day of surgery and 4 weeks postsurgery. Linear regression analyses were performed to identify presurgical biopsychosocial predictors of acute and subacute postsurgical pain.

Results

Average levels of postsurgical pain intensity and unpleasantness were as follows: 22.7 mm for acute pain intensity, 19.0 mm for acute pain unpleasantness, 10.3 mm for subacute pain intensity, and 11.7 mm for subacute pain unpleasantness. Pain expectancy predicted acute pain intensity (R² = 0.04, p = 0.047) and acute unpleasantness (R² = 0.06, p = 0.02). Perceived social support inversely predicted acute pain unpleasantness (R² = 0.04, p = 0.014).

Conclusion

Mild and moderate acute pain intensity and unpleasantness are common after breast cancer surgery, whereas levels of subacute pain intensity and unpleasantness are low. Pain expectancy predicts acute postsurgical pain intensity and unpleasantness, whereas expected social support inversely predicts acute postsurgical pain unpleasantness.

Psychological mechanisms of offset analgesia: The effect of expectancy manipulation

A frequently used paradigm to quantify endogenous pain modulation is offset analgesia, which is defined as a disproportionate large reduction in pain following a small decrease in a heat stimulus. The aim of this study was to determine whether suggestion influences the magnitude of offset analgesia in healthy participants. A total of 97 participants were randomized into three groups (hypoalgesic group, hyperalgesic group, control group). All participants received four heat stimuli (two constant trials and two offset trials) to the ventral, non-dominant forearm while they were asked to rate their perceived pain using a computerized visual analogue scale. In addition, electrodermal activity was measured during each heat stimulus. Participants in both intervention groups were given a visual and verbal suggestion about the expected pain response in an hypoalgesic and hyperalgesic manner. The control group received no suggestion. In all groups, significant offset analgesia was provoked, indicated by reduced pain ratings (p < 0.001) and enhanced electrodermal activity level (p < 0.01). A significant group difference in the magnitude of offset analgesia was found between the three groups (F[2,94] = 4.81, p < 0.05). Participants in the hyperalgesic group perceived significantly more pain than the hypoalgesic group (p = 0.031) and the control group (p < 0.05). However, the electrodermal activity data did not replicate this trend (p > 0.05). The results of this study indicate that suggestion can be effective to reduce but not increase endogenous pain modulation quantified by offset analgesia in healthy participants.

Assessment of patients' satisfaction with the postanesthesia care unit service at University Hospital in Al Khobar, KSA

Objectives

The quality of health care is individually and subjectively reflected through patients' level of satisfaction, as well as the optimality and effectiveness of the provided postoperative pain management. The provision of postanesthesia care unit (PACU) service in hospitals has led to overall positive outcomes, in addition to the enhancement of patients' satisfaction with the provided pain management service. This study assessed patients' level of satisfaction with PACU service at a university hospital and discussed different factors that might have contributed to the level of satisfaction.

Methods

A prospective cross-sectional study was carried out among patients after being discharged from PACU. The study took place at King Fahad Hospital of the University in Al Khobar, KSA between November 2021 and February 2022. The data were collected using a three-section predesigned questionnaire.

Results

Two hundred patients were included in this study. Nearly all patients (95.5%) were satisfied with the provided pain management service. Almost all patients (99.5%) indicated that the PACU staff was courteous and professional during the entire pain management service. More patients complained about pain before using analgesia and this difference was statistically significant (Z = 8.642; p < 0.001). The satisfaction rate was significantly higher in the older age group (>45 years) (Z = 2.114; p = 0.035), in patients with American Society of Anesthesiology (ASA) 3 physical status (H = 13.130; p = 0.001), and those with a previous surgical history (Z = 2.139; p = 0.032).

Conclusion

This study concluded that the level of patients' satisfaction with PACU service was high, and established a statistically significant association with age, ASA score, and previous surgical history. Healthcare providers should consider patient education and effective communication to increase patients' satisfaction level and improve the overall quality of care.

The effects of cannabidiol and analgesic expectancies on experimental pain reactivity in healthy adults: A balanced placebo design trial

Despite its frequent use for pain relief, no experimental pain research has tested the analgesic effects of cannabidiol (CBD) in humans. The goal of this study was to experimentally test the effects of CBD and expectancies for receiving CBD on human pain reactivity. Using a crossover, 2 × 2 factorial balanced placebo design, drug administration (given inactive substance or given active CBD) and verbal instruction sets (told inactive substance or told active CBD) were experimentally manipulated. Fifteen healthy adults each completed four separate experimental sessions. Participants were randomly assigned to different counterbalanced manipulation conditions at each session: control (told inactive-given inactive); expectancy (told active CBD-given inactive); drug (told inactive-given active CBD); and expectancy + drug (told active CBD-given active CBD). Primary outcomes were pain threshold, tolerance, intensity, unpleasantness, conditioned pain modulation (CPM), and offset analgesia (OA). There was a significant main effect of instructions on OA, such that the OA response was significantly larger when participants were told that they received CBD, regardless of drug content. Pain unpleasantness was significantly reduced in the drug, expectancy, and expectancy + drug conditions, relative to the control condition. The drug and expectancy conditions separately improved CPM, whereas the expectancy + drug and control conditions produced the lowest CPM change scores. We did not detect significant effects for pain threshold, tolerance, or intensity. Our results indicated that separate pain outcomes can be differentially affected by CBD and/or expectancies for receiving CBD. Future investigations of the psychological and pharmacological mechanisms underlying CBD analgesia are warranted. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The Influence of Expectancies on Pain and Function Over Time After Total Knee Arthroplasty

OBJECTIVE

Expectancies have a well-documented influence on the experience of pain, responses to treatment, and postsurgical outcomes. In individuals with osteoarthritis, several studies have shown that expectations predict increased pain and disability after total knee replacement surgery. Despite the growing recognition of the importance of expectancies in clinical settings, few studies have examined the influence of expectancies throughout postsurgical recovery trajectories. The objective of the present study was to examine the role of presurgical expectancies on pain and function at 6-week, 6-month, and 1-year follow-ups after total knee arthroplasty.

DESIGN AND PARTICIPANTS

Data were collected from patients scheduled for total knee arthroplasty 1 week before surgery and then at 6 weeks, 6 months, and 1 year after surgery. Correlational and multivariable regression analyses examined the influence of expectancies on patients' perceptions of pain reduction and functional improvement at each time point. Analyses controlled for age, sex, body mass index, presurgical pain intensity and function, pain catastrophizing, anxiety, and depression.

RESULTS

Results revealed that expectancies significantly predicted pain reduction and functional improvement at 1-year follow-up. However, expectancies did not predict outcomes at the 6-week and 6-month follow-ups. Catastrophizing and depressive symptoms emerged as short-term predictors of postsurgical functional limitations at 6-week and 6-month follow-ups, respectively.

CONCLUSIONS

The results suggest that targeting high levels of catastrophizing and depressive symptoms could optimize short-term recovery after total knee arthroplasty. However, the results demonstrate that targeting presurgical negative expectancies could prevent prolonged recovery trajectories, characterized by pain and loss of function up to 1 year after total knee arthroplasty.