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

Power of Words: Influence of Preexercise Information on Hypoalgesia after Exercise-Randomized Controlled Trial

PURPOSE

Exercise increases pressure pain thresholds (PPT) in pain-free individuals, known as exercise-induced hypoalgesia (EIH). Positive preexercise information can elicit higher EIH responses, but the effect of positive versus negative preexercise information on EIH is unknown. The primary aim of this randomized controlled trial was to compare EIH at the exercising thigh muscle after an isometric squat exercise between individuals receiving positive versus negative preexercise information about the effect of exercise on pain. Secondary aims were to compare EIH at nonexercising muscles between groups, and to investigate the relationship between participants' expectations and EIH.

METHODS

Eighty-three participants were randomly assigned to brief positive (n = 28), neutral (n = 28) or negative (n = 27) verbal information. The neutral information group was included in the study as a reference group. Pressure pain thresholds at the thigh and trapezius muscles were assessed before and after the intervention (i.e., preexercise information+squat exercise). Expectations of pain relief were assessed using a numerical rating scale (-10 [most negative] to 10 [most positive]).

RESULTS

Change in quadriceps and trapezius PPT after the squat exercise showed a large difference between the positive and negative information groups (quadriceps, 102 kPa; 95% confidence interval, 55-150; effect size, 1.2; trapezius, 41 kPa; 95% confidence interval, 16-65; effect size:, 0.9). The positive information group had a 22% increase in quadriceps PPT whereas the negative information group had a 4% decrease. A positive correlation was found between expectations and increase in PPT.

CONCLUSIONS

Negative preexercise information caused hyperalgesia after the wall squat exercise, whereas positive or neutral preexercise information caused hypoalgesia. Positive preexercise information did not change the magnitude of EIH compared with neutral information.

Optimizing expectations about endocrine treatment for breast cancer: Results of the randomized controlled psy-breast trial

Background

Medication side effects are strongly determined by non-pharmacological, nocebo mechanisms, particularly patients’ expectations. Optimizing expectations could minimize side effect burden. This study evaluated whether brief psychological expectation management training (EXPECT) optimizes medication-related expectations in women starting adjuvant endocrine therapy (AET) for breast cancer.

Method

In a multisite randomized controlled design, 197 women were randomized to EXPECT, supportive therapy (SUPPORT), or treatment as usual (TAU). The three-session cognitive-behavioral EXPECT employs psychoeducation, guided imagery, and side effect management training. Outcomes were necessity-concern beliefs about AET, expected side effects, expected coping ability, treatment control expectations, and adherence intention.

Results

Both interventions were well accepted and feasible. Patients’ necessity-concern beliefs were optimized in EXPECT compared to both TAU and SUPPORT, d = .41, p < .001; d = .40, p < .001. Expected coping ability and treatment control expectations were optimized compared to TAU, d = .35, p = .02; d = .42, p < 001, but not to SUPPORT. Adherence intention was optimized compared to SUPPORT, d = .29, p = .02, but not to TAU. Expected side effects did not change significantly.

Conclusion

Expectation management effectively and partly specifically (compared to SUPPORT) modified medication-related expectations in women starting AET. Given the influence of expectations on long-term treatment outcome, psychological interventions like EXPECT might provide potential pathways to reduce side effect burden and improve quality of life during medication intake.

Positive Treatment Expectancies Reduce Clinical Pain and Perceived Limitations in Movement Ability Despite Increased Experimental Pain: A Randomized Controlled Trial on Sham Opioid Infusion in Patients with Chronic Back Pain

BACKGROUND

Increasing evidence for the efficacy of analgesic placebo effects in laboratory studies with healthy persons raises the question whether placebos could be used to improve the treatment of pain patients. Expectancies play a central role in shaping analgesic placebo but also nocebo effects.

OBJECTIVES

We investigated to what extent a sham opioid infusion (saline solution) produces sustained clinically relevant placebo and nocebo effects in chronic back pain patients.

METHODS

Fifty-nine patients received the sham opioid infusion applied via a large drain dressing and were compared to 14 control patients without intervention (natural history, NH) while experimental pain stimuli were applied. All subjects were told that the infusion would decrease pain although in rare cases pain increase would be possible (induction of expectancy). In addition, conditioning was introduced where the participants either experienced a decrease in experimental pain (n = 17; placebo conditioning), an increase (n = 21; nocebo conditioning), or no change (n = 21, no conditioning).

RESULTS

Compared to the NH group, all infusion groups showed positive treatment expectancies and significantly (p < 0.001) reduced clinical back pain (primary outcome) and pain-related disability (secondary outcome, assessed by self-reported functional capacity and perceived impairment of mobility). Even the nocebo conditioned group experiencing increased experimental pain developed positive treatment expectancies followed by reduced pain experience. Positive treatment expectancies and relief in clinical back pain were significantly positively correlated (r = 0.72, p < 0.01).

CONCLUSIONS

These findings suggest that it may be beneficial to explicitly shape and integrate treatment expectancies into clinical pain management.

Prior Therapeutic Experiences, Not Expectation Ratings, Predict Placebo Effects: An Experimental Study in Chronic Pain and Healthy Participants

INTRODUCTION

Many clinical trials fail because of placebo responses. Prior therapeutic experiences and patients' expectations may affect the capacity to respond to placebos in chronic disorders.

OBJECTIVE

The scope of this study in 763 chronic orofacial pain and healthy study participants was to compare the magnitude and prevalence of placebo effects and determine the putative role of prior therapeutic experiences vs. expectations.

METHODS

We tested placebo propensity in a laboratory setting by using 2 distinct levels of individually tailored painful stimulations (high pain and low pain) to reinforce expectations and provide a hypoalgesic experience (conditioning phase). Afterwards, both levels of pain were surreptitiously set at a moderate pain level to test for placebo effects (testing phase). Pain and expectation ratings were assessed as primary outcomes using visual analog scales.

RESULTS

In both chronic pain and healthy participants, placebo effects were similar in magnitude, with the larger prevalence of responders in the healthy participants. Although chronic pain participants reported higher pain relief expectations, expectations did not account for the occurrence of placebo effects. Rather, prior experience via conditioning strength mediated placebo effects in both pain and healthy participants.

CONCLUSIONS

These findings indicate that participants with chronic pain conditions display robust placebo effects that are not mediated by expectations but are instead directly linked to prior therapeutic experiences. This confirms the importance of assessing the therapeutic history while raising questions about the utility of expectation ratings. Future research is needed to enhance prediction of responses to placebos, which will ultimately improve clinical trial designs.

HAPPY - Humanity Assurance Protocol in interventional radiotheraPY (brachytherapy) - an AIRO Interventional Radiotherapy Study Group project

Purpose

Interventional procedures may produce emotional distress, particularly in interventional radiotherapy (IRT, brachytherapy - BT). This work would like to propose a series of recommendations/interventions to guarantee a human approach in order to favor the psychological well-being of the patient during interventional radiotherapy.

Material and methods

Thirty patients affected by gynecological cancer and treated with endovaginal high-dose-rate IRT (HDR-IRT) were selected from January to March 2019. A specific Multiprofessional Task Group (MTG) was defined in order to analyze the needs of patients. Each component of the task group spoke with the patients to examine their needs and to investigate their fears and perception. The results of the MTG were subjected to evaluation by an Expert Team (ET) of 4 physicians from 4 different institutions for a final evaluation. Both teams discussed the patient's needs to generate a list of necessary interventions to fulfill every single need in order to obtain their inner well-being. Another team (Master Team - MT) performed an independent check.

Results

All patients suggest that the main issue is the "lack of information and fear of the unknown". The fear of feeling pain was a significant source of concern, sadness, and vulnerability for the majority of the patients (76.6%). All patients do not appreciate the use of the word "bunker" to describe the treatment place. In 33.3% of patients the word "brachytherapy" (often unknown) determines insecurity while the term "interventional radiotherapy" reassures. Ninety percent of patients preferred to perform the external genital depilation at home and 80% of them would like the bladder catheter to be placed immediately before the procedure. MTG and ET defined nine "HAPPY recommendations". The MT approved the protocol without changes.

Conclusions

The aim of the present paper was to produce a protocol consisting in intervention that could improve the internal serendipity and emotional state of patients who underwent HDR-IRT.

What is new in the psychology of chronic itch?

Itch is often regarded as unpleasant or bothersome and is accompanied by symptoms of distress and impairments in daily life. The biopsychosocial model of chronic itch describes how psychological factors can contribute to the improvement or exacerbation of chronic itch and related scratching behaviour. Recent research underlines the important role of cognitive-affective information processing, such as attention, affect and expectancies. This may not only play a role for acute itch states, but may particularly apply to the process of itch chronification, for example, due to the vicious cycle in which these factors shape the experience of itch. The present paper focuses on new insights into the relation between itch and the cognitive-affective factors of attention, affect and expectancies. These factors are thought to play a possible aggravating role in itch in the long term and have received increasing attention in the recent empirical literature on maintaining and exacerbating factors for chronic physical symptoms. Possible psychophysiological and neurobiological pathways regarding these factors are discussed, as well as possible intervention methods.

Placebo and Nocebo Effects Across Symptoms: From Pain to Fatigue, Dyspnea, Nausea, and Itch

Placebo and nocebo effects are, respectively, the helpful and harmful treatment effects that do not arise from active treatment components. These effects have thus far been researched most often in pain. It is not yet clear to what extent these findings from pain can be generalized to other somatic symptoms. This review investigates placebo and nocebo effects in four other highly prevalent symptoms: dyspnea, fatigue, nausea, and itch. The role of learning mechanisms (verbal suggestions, conditioning) in placebo and nocebo effects on various outcomes (self-reported, behavioral, and physiological) of these different somatic symptoms is explored. A search of experimental studies indicated that, as in pain, the combination of verbal suggestion and conditioning is generally more effective than suggestion alone for evoking placebo and nocebo effects. However, conditioning appears more and verbal suggestions less relevant in symptoms other than pain, with the exception of placebo effects on fatigue and nocebo effects on itch. Physiological measures, such as heart rate, lung function, or gastric activity, are rarely affected even when self-reported symptoms are. Neurobiological correlates are rarely investigated, and few commonalities appear across symptoms. Expectations generally predict placebo and nocebo effects for dyspnea and itch but seem less involved in fatigue and nausea. Individual characteristics do not consistently predict placebo or nocebo effects across symptoms or studies. In sum, many conclusions deriving from placebo and nocebo pain studies do appear to apply to other somatic symptoms, but a number of important differences exist. Understanding what type of learning mechanisms for which symptom are most likely to trigger placebo and nocebo effects is crucial for generalizing knowledge for research and therapies across symptoms and can help clinicians to optimize placebo effects in practice.

The placebo and its effects: A psychoneuroendocrinological perspective

Placebos are usually employed deceptively in clinical trials in order to control for non-specific effects. However, since placebos themselves have been found to cause clinically relevant changes and in some cases are indistinguishable from the verum they are tested against, this theoretically inert, but practically effective intervention has become a scientific discipline in its own right. In this review, it is argued that placebos are generic and genuine biopsychosocial interventions and as such are highly interesting candidates for a psychoneuroendocrinological perspective. Yet, despite a considerable conceptual proximity between explanatory models of placebos and their effects with psychoneuroendocrine models and findings, placebos have thus far not been subject to systematic psychoneuroendocrine examination. Consequently, it would be highly interesting and informative to make placebos the target of psychoneuroendocrine scrutiny.

Assessment of patients' expectations: development and validation of the Expectation for Treatment Scale (ETS)

OBJECTIVE

To develop a short self-report instrument for the assessment of expectations (Expectation for Treatment Scale(ETS)) using acupuncture as a case example.

DESIGN

A cross-sectional assessment with retest after 1 week.

SETTING

A web-based survey with patients suffering from pain.

METHODS

In a three-step approach, we reduced the initially collected number of items from 17 to 9 and to 5, including expectations about coping ability, vitality, physical health and reduction of patient complaints. Items were selected according to internal consistency (Cronbach's alpha); convergent and divergent validities with related constructs (optimism, pessimism, resilience, perceived sensitivity to medicines, depression and others); 1-week retest reliability (intraclass correlation coefficient (ICC)); and exploratory and confirmatory factor analysis (CFA).

RESULTS

A total of 102 patients suffering from pain were included, and 54 of these patients completed the retest assessment. The final version of the ETS consisted of five items and had an excellent Cronbach's alpha (0.90), with 72.33% variance on one single factor. Depression, pessimism and perceived sensitivity to medicines showed positive correlations with our expectation measure (r=0.23, r=0.20 and r=0.34, respectively); the correlation between the ETS and optimism was low (r=-0.07) and no correlation between the ETS and resilience was found (r=-0.07). Convergent validity was confirmed with a high correlation (r>0.90) between ETS and a treatment-specific measure of expectations. The retest ICC was 0.86, which showed high stability over 1 week. A CFA (n=439) with data from patients with low back pain confirmed the single-factor structure of the instrument.

CONCLUSION

The ETS showed strong psychometric properties and covered a distinct construct. As the next step, the ETS might be implemented in different clinical conditions and settings to investigate psychometrics and its predictive power for treatment outcomes.

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

Introduction:

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

Objectives:

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

Methods:

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

Results:

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

Conclusion:

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

Optimizing Expectations via Mobile Apps: A New Approach for Examining and Enhancing Placebo Effects

There is growing interest in interventions that enhance placebo responses in clinical practice, given the possibility that this would lead to better patient health and more effective therapy outcomes. Previous studies suggest that placebo effects can be maximized by optimizing patients' outcome expectations. However, expectancy interventions are difficult to validate because of methodological challenges, such as reliable blinding of the clinician providing the intervention. Here we propose a novel approach using mobile apps that can provide highly standardized expectancy interventions in a blinded manner, while at the same time assessing data in everyday life using experience sampling methodology (e.g., symptom severity, expectations) and data from smartphone sensors. Methodological advantages include: 1) full standardization; 2) reliable blinding and randomization; 3) disentangling expectation effects from other factors associated with face-to-face interventions; 4) assessing short-term (days), long-term (months), and cumulative effects of expectancy interventions; and 5) investigating possible mechanisms of change. Randomization and expectancy interventions can be realized by the app (e.g., after the clinic/lab visit). As a result, studies can be blinded without the possibility for the clinician to influence study outcomes. Possible app-based expectancy interventions include, for example, verbal suggestions and imagery exercises, although a large number of possible interventions (e.g., hypnosis) could be evaluated using this innovative approach.

The impact of valence framing on response expectancies of side effects and subsequent experiences: a randomised controlled trial

Objective: Pre-treatment side effect expectancies often influence subsequent experiences; however, expectancy-based reduction strategies are lacking. We explored whether framing information about adverse responses (in positive or negative formats) altered expectancies and experiences of a cold pressor task. We further investigated associations between expectancies and experiences, to inform potential interventions. Design: Healthy volunteers (N = 134), randomised to receive positively- or negatively-framed pre-cold pressor task information, self-rated 12 expectancies for cold pressor experiences, emotional state and coping style. Main Outcome Measures: Self-reports of the same 12-experiences (recorded during and after the experiment) were assessed. Results: Framing had minimal impact on expectancies and experiences; however, discomfort threshold (p = .08, d = 0.22) showed a trend in the expected direction. Hierarchical regressions revealed expectancies uniquely, significantly predicted 6-23% of the variance for 11 subsequent experiences. Following a popular charity event (Ice Bucket Challenge), all participants showed higher 'discomfort thresholds' (p = .001, d = 0.59), and those in the negative frame reported more overall 'discomfort' (p = .01, d = 0.60) than participants in the positive condition. Conclusion: Expectancies uniquely influenced subsequent cold pressor experiences. Framing had minimal impact in this 'analogue' medical setting, only influencing 'discomfort threshold'. 'Discomfort threshold' and overall 'discomfort' were also impacted by a social media challenge, highlighting a potential area for intervention.

Use of Manual Therapy for Posterior Pelvic Girdle Pain

Use of manual therapies in the treatment of posterior pelvic pain is a common practice. The rationale for use of manual therapies is often associated with the structural movement of the sacroiliac joint. Increasing evidence has shown this not to be the case, as manual therapy's effect is more neurophysiological in nature. This article seeks to clarify the difference between the two explanations as well as to expand upon outside influences such as expectations, therapeutic alliance, and equipoise that may influence the outcome of treatment. Treatment effects may be maximized with manual therapy if clinicians have an understanding of the role of each of these variables in their treatment approach.

Development and validation of the Treatment Expectations in Chronic Pain Scale

OBJECTIVES

To develop and examine the psychometric properties of the Treatment Expectations in Chronic Pain (TEC) scale, a brief measure of treatment expectations of chronic non-cancer pain treatment.

DESIGN

A cross-sectional study design was used.

METHODS

After conducting a literature review and expert discussions, a preliminary version of the TEC scale was developed. Cognitive interviews with 10 clinicians and 14 patients were conducted to examine the scale's face validity and item wording. Last, two hundred and five patients on the waitlist for a multidisciplinary pain treatment centre completed a battery of self-report questionnaires to examine the TEC scale's reliability and construct validity. Mokken scale analysis was conducted to select the final items. Reliability (Cronbach's alpha and Guttman's lambda² ) and construct validity (Pearson correlations) were assessed.

RESULTS

The final scale was composed of nine items that each measured ideal and predicted expectations about process and outcome of treatment. Mokken scale analysis showed the presence of two subscales: ideal and predicted expectations. The TEC scale had good internal consistency (α = 0.876-0.869) and adequate discriminant validity as assessed by its low correlation with measures of depression, anxiety, and quality of life (r = -.038 to .114). The scale had however low correlation with a theoretically related measure of optimism (r = .240).

CONCLUSION

The TEC scale is a reliable scale measuring pain treatment expectation. Further evaluation of its psychometric properties is needed. The scale has the potential to deepen our understanding of the role treatment expectations play in chronic non-cancer pain treatment response. Statement of contribution What is already known on this subject? Expectations play a role in pain perception and the response to pain treatment Patients' expectations about pain and its management are associated with treatment satisfaction The absence of a validated tool to measure treatment expectations in chronic non-cancer pain prevents further exploration and understanding of the role of expectations in the context of multidisciplinary pain treatment . What does this study add? A new, reliable 9-item scale measuring treatment expectations among chronic non-cancer pain patients attending specialized multidisciplinary pain clinics .

Influencing Side-Effects to Medicinal Treatments: A Systematic Review of Brief Psychological Interventions

Background: Nocebo effects contribute to a large proportion of the non-specific side-effects attributed to medications and are mainly generated through negative expectations. Previous reviews show that interventions designed to change participants' expectations have a small effect on pain experience. They are also effective in reducing side-effects caused by exposure to sham medications. To date, there has been no review of the influence of such interventions on symptoms attributed to real medicinal treatments. Objective: To review studies using a randomized controlled design testing the effect of brief psychological interventions compared to usual practice on the side-effect experience to medicinal treatments in healthy volunteers and patients. Methods: We searched Web of Science, Scopus, Medline, PsycINFO, PsycARTICLES, and Cochrane CENTRAL using search terms for randomized controlled trials along with "nocebo," "placebo effect," "medication," "side-effects," and associated terms. Studies were eligible if they studied a human population, used an active medicine, delivered a brief psychological intervention intended to influence side-effect reporting compared to usual care or no intervention, and used a randomized controlled design. Because of the heterogeneity of the literature we used a narrative synthesis and assessed evidence quality using the GRADE approach. Results: Our database search and supplementary search of the reference sections of included studies retrieved 50,140 citations. After screening, full text review and manual reference searches, 27 studies were included. The quality of the studies and evidence was judged to be low. The strongest and most consistent effect came from omitting side-effect information, although surprisingly de-emphasizing side-effects did not affect side-effect reporting. Other techniques, including priming, distraction, and altering the perception of branding, produced mixed results. Conclusion: Brief psychological interventions can influence side-effect reporting to active medications. Research is currently investigating new ways to de-emphasize side-effects whilst still upholding informed consent, but larger confirmatory trials with suitable control groups are needed. The literature in this area would be improved by more detailed reporting of studies.

What do you expect? Catastrophizing mediates associations between expectancies and pain-facilitatory processes

BACKGROUND

Pain expectancies are associated with altered pain sensitivity in individuals with chronic pain. However, little is known about the processes by which pain expectancies impact pain processing. This study assessed the association between pain expectancies and temporal summation (TS) of pain, and examined whether pain catastrophizing mediated this association.

METHODS

In this cross-sectional study, participants (437 chronic low back pain [CLBP] patients, 115 controls) completed self-report measures of pain intensity, pain expectancies and pain catastrophizing before undergoing psychophysical pain-testing procedures designed to assess mechanical TS of mechanical pain. Pearson's correlations examined the associations between study variables in CLBP patients and controls. Bootstrapping mediation analyses assessed the mediating role of pain catastrophizing on the association between pain expectancies and TS of pain.

RESULTS

Temporal summation of pain was significantly associated with pain expectancies (r = 0.113) and pain catastrophizing (r = 0.171) in CLBP patients. Results of mediation analyses revealed that pain catastrophizing mediated the relationship between pain expectancies and TS of pain in CLBP patients (ab = 0.309, 95% CI = 0.1222-0.5604), but not in healthy controls (ab = -0.125, 95% CI = -0.5864 to 0.0244).

CONCLUSIONS

The findings from this study suggest that compared to controls, CLBP patients show increased sensitivity to mechanical pain procedures and enhanced pain-facilitatory processing, proving further evidence for changes in central nervous system pain processing in CLBP patients. Our results also suggest that pain catastrophizing may be the mechanism by which pain expectancies are associated with TS of pain in CLBP patients.

SIGNIFICANCE

Individuals with chronic low back pain who expect higher levels of pain and catastrophize about their pain are more likely to experience altered pain sensitivity. Our results point to catastrophizing as a mechanism of action through which psychological factors may operate and lead to the development and maintenance of chronic low back pain.

The Use of Expectancy and Empathy When Communicating With Patients With Advanced Breast Cancer; an Observational Study of Clinician-Patient Consultations

Background: Information provision about prognosis, treatments, and side-effects is important in advanced cancer, yet also associated with impaired patient well-being. To counter potential detrimental effects, communication strategies based on placebo and nocebo effect mechanisms might be promising to apply in daily practice. This study aimed to provide more insight into how often and how oncologists use expectancy and empathy expressions in consultations with patients with advanced breast cancer. Methods: Forty-five consultations between oncologists and patients were audiotaped. To determine how often expectancy and empathy expressions were used, a coding scheme was created. Most consultations (n = 33) were coded and discussed by two coders, and the remaining 13 were coded by one coder. To determine how expectancy and empathy expressions were used, principles of inductive content analysis were followed. Results: Discussed evaluation (i.e., scan) results were good (n = 26,58%) or uncertain (n = 12,27%) and less often bad (n = 7,15%). Uncertain expectations about prognosis, treatment outcomes, and side effects occurred in 13, 38, and 27 consultations (29%, 85%, and 56%), followed by negative expectations in 8, 26, and 28 consultations (18%, 58%, and 62%) and positive expectations in 6, 34, and 17 consultations (13%, 76%, and 38%). When oncologists provided expectancy expressions, they tapped into three different dimensions: relational, personal, and explicit. Positive expectations emphasized the doctor-patient relationship, while negative expectations focused on the severity of the illness, and uncertainty was characterized by a balance between (potential) negative outcomes and hope. Observed generic or specific empathy expressions were regularly provided, most frequently understanding (n = 29,64% of consultations), respecting (n = 17,38%), supporting (n = 16,36%), and exploring (n = 16,36%). A lack of empathy occurred less often and contained, among others, not responding to patients' emotional concerns (n = 13,27% of consultations), interrupting (n = 7,16%), and an absence of understanding (n = 4,9%). Conclusion: In consultations with mainly positive or uncertain medical outcomes, oncologists predominantly made use of uncertain expectations (hope for the best, prepare for the worst) and used several empathic behaviors. Replication studies, e.g., in these and other medical situations, are needed. Follow-up studies should test the effect of specific communication strategies on patient outcomes, to counter potential negative effects of information provision. Studies should focus on uncertain situations. Ultimately, specific placebo and nocebo effect-inspired communication strategies can be harnessed in clinical care to improve patient outcomes.

Self-Management of Cardiac Pain in Women: A Meta-Summary of the Qualitative Literature

Symptom recognition and self-management is instrumental in reducing the number of deaths related to coronary artery disease (CAD) in women. The purpose of this study was to synthesize qualitative research evidence on the self-management of cardiac pain and associated symptoms in women. Seven databases were systematically searched, and the concepts of the Individual and Family Self-Management Theory were used as the framework for data extraction and analysis. Search strategies yielded 22,402 citations, from which 35 qualitative studies were included in a final meta-summary, comprising data from 769 participants, including 437 (57%) women. The available literature focused cardiac pain self-management from a binary sex and gender perspective. Ethnicity was indicated in 19 (54%) studies. Results support individualized intervention strategies that promote goal setting and action planning, management of physical and emotional responses, and social facilitation provided through social support.

Beliefs about back pain and pain management behaviours, and their associations in the general population: A systematic review

Previous mass media campaigns have aimed to influence how people manage back pain, with mixed success. Campaigns should target beliefs which are related to the behaviours they aim to change. This systematic review brings together research that has measured the prevalence of beliefs about back pain in the general population and factors associated with these beliefs, including future pain‐related outcomes. Five databases were searched up until April 2017. Quantitative studies which reported a measure of agreement with a belief about back pain, cross‐sectional associations, or associations between beliefs and future outcomes were eligible. Eligibility was assessed and data extracted independently by two authors. Results were tabulated and narratively synthesized. Nineteen studies from 10 countries were eligible (median study n [IQR] = 990.5 [524.75–2387.5]). Beliefs were measured using eight questionnaires and 57 stand‐alone items. Beliefs about back pain's negative consequences were common across countries and populations, whereas most samples did not hold fear‐avoidance beliefs. Beliefs about back pain's consequences were associated with pain and disability, but only one study investigated this specific relationship prospectively. No studies investigated whether beliefs are associated with future pain management behaviours. Agreement with certain beliefs (e.g. about negative consequences) was associated with sociodemographic characteristics (e.g. older age) and poorer self‐rated health. Interventions may benefit from targeting beliefs about the perceived negative consequences of back pain in these populations. However, future research should explore how beliefs prospectively influence the management of back pain.

Significance

This review brings together studies which have assessed the prevalence of beliefs about back pain, and factors associated with holding them. It highlights that whether or not these beliefs represent important determinants of how people manage pain remains unknown.

Optimizing Placebo and Minimizing Nocebo to Reduce Pain, Catastrophizing, and Opioid Use: A Review of the Science and an Evidence-Informed Clinical Toolkit

Pain, a noxious psychosensory experience, motivates escape behavior to assure protection and survival. Psychological factors alter the experience and trajectory of pain, as well as behavior and treatment response. In the context of pain, the placebo effect (expectation for pain relief) releases endogenous opioids and facilitates analgesia from exogenously administered opioids. Nocebo hyperalgesia (expectation for persistent or worsening pain) opposes endogenous opioid analgesia and patient engagement in prescription opioid tapering. Reductions in nocebo hyperalgesia and pain catastrophizing may enhance descending modulation of pain, mediate adaptive structural brain changes and promote patient engagement in opioid tapering. Interventions that minimize nocebo and optimize placebo may adaptively shape the central nervous system toward pain relief and potentially opioid reduction. Here we provide a critical description of catastrophizing and its impact on pain, placebo and nocebo effects. We also consider the importance of minimizing nocebo and optimizing placebo effects during prescription opioid tapering, and offer a clinical toolkit of resources to accomplish these goals clinically.

Clinical Use of Placebo Effects in Patients With Pain Disorders

The analgesic placebo effect is well documented by numerous studies. Many important influencing factors, however, are yet to be discovered. In the arena of placebo effects and clinical implications, expectancies play a central role. Expectancies are shaped by processes of classical and social learning as well as verbal instructions and are strongly related to emotional factors. Expectancies trigger a cascade of endogenous opioids and non-opioids, which alter the experience of pain. For clinical application it is important to know, that placebo research yields ethical possibilities to use placebo effects without deception and without using placebos. Since placebo effects contribute to responses to active analgesics, it is feasible to enhance patients' benefits from pain treatments by increasing the additional placebo effect. There are several possibilities to use the placebo effects via shaping and adapting information about analgesic medication and via associating medication intake with a positive context. A positive patient-clinician communication atmosphere is very important to generate clinically meaningful placebo effects in pain medicine.

Implications of Placebo and Nocebo Effects for Clinical Practice: Expert Consensus

BACKGROUND

Placebo and nocebo effects occur in clinical or laboratory medical contexts after administration of an inert treatment or as part of active treatments and are due to psychobiological mechanisms such as expectancies of the patient. Placebo and nocebo studies have evolved from predominantly methodological research into a far-reaching interdisciplinary field that is unravelling the neurobiological, behavioural and clinical underpinnings of these phenomena in a broad variety of medical conditions. As a consequence, there is an increasing demand from health professionals to develop expert recommendations about evidence-based and ethical use of placebo and nocebo effects for clinical practice.

METHODS

A survey and interdisciplinary expert meeting by invitation was organized as part of the 1st Society for Interdisciplinary Placebo Studies (SIPS) conference in 2017. Twenty-nine internationally recognized placebo researchers participated.

RESULTS

There was consensus that maximizing placebo effects and minimizing nocebo effects should lead to better treatment outcomes with fewer side effects. Experts particularly agreed on the importance of informing patients about placebo and nocebo effects and training health professionals in patient-clinician communication to maximize placebo and minimize nocebo effects.

CONCLUSIONS

The current paper forms a first step towards developing evidence-based and ethical recommendations about the implications of placebo and nocebo research for medical practice, based on the current state of evidence and the consensus of experts. Future research might focus on how to implement these recommendations, including how to optimize conditions for educating patients about placebo and nocebo effects and providing training for the implementation in clinical practice.

The effects of a gamified approach avoidance training and verbal suggestions on food outcomes

There is initial support for the effectiveness of approach-avoidance trainings in altering food-related health behaviors. Furthermore, outcome expectancies induced by verbal suggestions might optimize the effectiveness of these interventions, as shown in placebo research. The present study investigated the effectiveness of a gamified approach-avoidance training on food-related outcomes and whether verbal suggestions could strengthen those effects. A total of 120 participants were randomly assigned to 1 of 4 conditions: serious gaming only, verbal suggestions only, serious gaming combined with verbal suggestions, or a gaming control condition. Virtual food preference and food choice were assessed with a food choice task, with pairs differing in healthiness or in healthiness and attractiveness. Implicit food preference was assessed with an Implicit Association Test and food intake with a bogus taste test. Participants in both serious gaming conditions made healthier food choices for pairs differing in healthiness and attractiveness and had healthier implicit food preferences compared to gaming control. No effects were found on food intake. These findings provide the first preliminary support for the effects of a gamified approach-avoidance training on virtual food choice and implicit food preference. Future studies should further elucidate these effects, also in other health domains such as physical activity.

Understanding rationales for acupuncture treated individuals' beliefs in acupuncture effects, to be able to maximize therapeutic results: A qualitative analysis

OBJECTIVE

To investigate how individuals expressed rationales for their beliefs regarding efficacy of acupuncture.

METHODS

Qualitative data from participants of two different randomized sham-controlled trials, of relaxing (non-cancer volunteers of the general population) or antiemetic (patients with cancer undergoing radiotherapy) effects of acupuncture was analyzed. Participants (n = 441) received genuine (n = 120 and n = 100) or sham (n = 121 and n = 100) (telescopic blunt sham-needle) relaxing or antiemetic acupuncture. The participants (n = 428; 97% response rate) expressed their belief regarding the efficacy of acupuncture, and n = 264 delivered qualitative rationales for their belief, analyzed using qualitative content analysis.

RESULTS

Of the 428 participants, 35 (8%) believed entirely that the acupuncture was effective, 209 (49%) believed much, 136 (32%) believed moderately, 39 (9%) believed a little, and 9 (2%) did not believe that the acupuncture was effective. Five categories and seven subcategories represented the meaning units of the central message of the rationales for the treatment belief. Participants with positive beliefs (believed entirely/much, n = 244) presented rationales related to: "Experienced positive effects", "Knowledge regarding effect-mechanisms of acupuncture", and "General trustworthiness of acupuncture". Participants with more negative beliefs (believed a little or not, n = 48) presented rationales related to: "Lack of feasibility of the acupuncture", "Varying effects", and "The effect is individual, not available for everybody".

CONCLUSION

In order to strengthen acupuncture treated patients' beliefs in the efficacy of acupuncture during clinical practice or research, acupuncture therapists may consider emphasizing these aspects in the therapeutic situation.

Pain rewarded: hyperalgesic and allodynic effect of operant conditioning in healthy humans-protocol for a systematic review and meta-analysis

BACKGROUND

'Pain rewarded' is a hypothesis wherein acute pain sufferers are exposed to reinforcers and punishers from their environment that shape their behaviour, i.e. pain responses. Such a point of view has been taken for granted by many clinicians and researchers although existing evidence has not yet been systematically summarized. This planned systematic review and meta-analysis is aiming to summarize the research findings on pain modulation (hyperalgesic effect) and pain elicitation (allodynic effect) resulting from operant conditioning procedures in healthy humans.

METHODS

The systematic review will be performed by searching for articles indexed in PubMed database, Cochrane Register of Controlled Trials (CENTRAL), Web of Science™, ScienceDirect, EBSCO database, PsycINFO, MEDLINE, PsycARTICLES and CINAHL. Studies will be included if they investigate healthy humans, exposed to modulation or elicitation of a pain experience induced by operant conditioning. Studies will be screened for eligibility and risk of bias by two independent assessors. Narrative and meta-analytical syntheses are planned.

DISCUSSION

Data will be pooled and analyzed qualitatively and quantitatively (if possible) in order to advance the understanding of pain mechanisms, especially the development of chronic pain. This systematic review will guide the planning of future experiments and research by summarizing important technical details of conditioning procedures in healthy humans.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017051763.

Psychedelics and hypnosis: Commonalities and therapeutic implications

BACKGROUND

Recent research on psychedelics and hypnosis demonstrates the value of both methods in the treatment of a range of psychopathologies with overlapping applications and neurophenomenological features. The potential of harnessing the power of suggestion to influence the phenomenological response to psychedelics toward more therapeutic action has remained unexplored in recent research and thereby warrants empirical attention.

AIMS

Here we aim to elucidate the phenomenological and neurophysiological similarities and dissimilarities between psychedelic states and hypnosis in order to revisit how contemporary knowledge may inform their conjunct usage in psychotherapy.

METHODS

We review recent advances in phenomenological and neurophysiological research on psychedelics and hypnosis, and we summarize early investigations on the coupling of psychedelics and hypnosis in scientific and therapeutic contexts. Results/outcomes: We highlight commonalities and differences between psychedelics and hypnosis that point to the potential efficacy of combining the two in psychotherapy. We propose multiple research paths for coupling these two phenomena at different stages in the preparation, acute phase and follow-up of psychedelic-assisted psychotherapy in order to prepare, guide and integrate the psychedelic experience with the aim of enhancing therapeutic outcomes.

CONCLUSIONS/INTERPRETATION

Harnessing the power of suggestion to modulate response to psychedelics could enhance their therapeutic efficacy by helping to increase the likelihood of positive responses, including mystical-type experiences.

What is the relative contribution of biological and psychosocial factors to the generation of hypoxia headache?

BACKGROUND

The biopsychosocial model claims that illness is generated by both biological and psychosocial factors. Accordingly, several studies have shown that both factors contribute to the generation of pain.

AIMS

The aim of the present study is to manipulate biological, psychological, and social factors in hypobaric hypoxia headache in order to understand their relative contribution to the generation of headache pain.

METHODS

Healthy subjects were subdivided into three groups and brought to our high-altitude labs for the assessment of hypoxia-induced headache, blood oxygen saturation (SO2), prostaglandins, and cortisol during the first 24 h after arrival. The first group did not undergo any manipulation. The second group (negative expectation) was told that severe headache would occur if SO2 dropped to less than 80% and their oximeters were set to display a saturation of 75%, even though real SO2 was much higher. The third group (negative expectation and social interaction) underwent the same manipulation as the second group, but these subjects spent the night together with people experiencing headache and insomnia.

RESULTS

Although none of the three groups differed significantly for SO2, the second group, compared to the first, experienced more severe headache and showed an increase in prostaglandins and cortisol. The third group, compared to the second group, showed a further increase of headache as well as of prostaglandin (PG) E2 and cortisol.

CONCLUSIONS

These findings indicate that biological, psychological, and social factors are additive not only in the generation of headache but also for the biochemical changes related to hypoxia.

Placebo effects of a sham opioid solution: a randomized controlled study in patients with chronic low back pain

This study tested the experimental placebo effect in a group of chronic pain patients. Forty-eight patients having chronic back pain participated in a randomized clinical trial that tested the efficacy of a sham opioid solution (NaCl) compared with an alleged neutral, completely inactive solution (NaCl). We shaped the placebo effect by 2 interventions: verbal instruction and conditioning. The patients were either told that the "solution reduces pain and improves physical capacity" or the "solution is neutral, a placebo." Half of each group was additionally conditioned (coupling solution with reduced experimental pain), yielding 4 subgroups with 12 participants each. Outcome measures were as follows: the patients' clinical back pain ratings and acute pain ratings (both examined by numerical rating scale 0-10) and self-rated functional capacity (0%-100%; time required for the exercise). Expected pain relief before and after solution intake was also assessed. The inactive solution (NaCl), when presented as an effective treatment (sham "opioid" solution), induced placebo analgesia as evident in lower ratings of the patients' clinical back pain (F(3.12,144.21) = 25.05, P < 0.001), acute pain ratings (F(1.99,87.40) = 18.12, P < 0.01), and time needed to complete a series of daily activities exercises (F(1,44) = 8.51, P < 0.01) as well as increased functional capacity (F(1,44.00) = 19.42, P < 0.001). The 2 manipulations (instruction and conditioning) changed pain expectations, and they were maintained in both sham opioid groups. The results suggest that it may be clinically useful to explicitly integrate placebo analgesia responses into pain management.

Effects of acute psychological stress on placebo and nocebo responses in a clinically relevant model of visceroception

There is evidence to suggest a role of emotions in placebo and nocebo effects, but whether acute psychological stress changes the magnitude of placebo or nocebo responses has not been tested. In a clinically relevant model of visceroception, we assessed effects of acute psychological stress on changes in urgency and pain in response to positive or negative treatment suggestions. In 120 healthy volunteers, perceived urge-to-defecate and pain in response to individually calibrated rectal distensions were measured with visual analogue scales during a BASELINE. Participants then underwent the Trier Social Stress Test (N = 60) or a simple cognitive task (control, N = 60) and were randomized to positive (placebo), negative (nocebo), or neutral treatment information regarding intravenous administration of saline. The series of distensions was repeated, and changes in visual analogue scales from BASELINE to TEST were compared between groups using analysis of covariance and planned post hoc tests. Treatment information emerged as a main factor (P <0.001), supporting treatment information effects for both urgency and pain. Effects for urgency were modulated by stress (interaction effect: P <0.05): Positive information reduced urgency (P = 0.025), while negative information increased urgency (P = 0.026) only in stressed groups. For pain, effects of stress emerged for nocebo responses, which were only evident in stressed groups (P = 0.009). This is the first experimental study supporting effects of acute psychological stress on placebo and nocebo responses in visceroception. Results call for mechanistic as well as patient studies to assess how psychological stress shapes patients' treatment expectations and thereby affects health outcomes.

Nocebo Effects: Neurobiological Mechanisms and Strategies for Prevention and Optimizing Treatment

Psychosocial and contextual factors, such as patient-physician relationship, prior treatment experience, and treatment expectation, can either improve or compromise treatment efficacy. These phenomena are commonly specified as placebo and nocebo effects. As placebo and nocebo effects can influence symptom development, adverse event rate, and treatment efficacy, it is crucial to be aware of these effects and to develop strategies for prevention to optimize treatment outcomes. While experimental studies have made substantial progress in elucidating the psychosocial and neurobiological mechanisms underlying placebo effects, the detailed mechanisms of nocebo effects remain largely unexplored. A better understanding of these mechanisms promises to facilitate the development of easy-to-use strategies in clinical care to improve overall treatment outcomes and patient satisfaction.

Expectations about the effectiveness of pain- and itch-relieving medication administered via different routes

BACKGROUND

Placebo effects on pain have been found to vary in size for different routes of medication administration (e.g. oral vs. injection). This has important implications for both clinical research and practice. To enhance our understanding of these differential placebo effects, research on the underlying expectations about multiple routes and symptoms other than pain is vital.

METHODS

A cross-sectional, Internet-based survey was conducted in a representative sample of the Dutch population (n = 508). Respondents rated the expected effectiveness of pain- and itch-relieving medication in six forms, representing oral, injection and topical routes of administration.

RESULTS

Injected medication was expected to be most effective for relieving pain, and topical medication for relieving itch. Furthermore, exploratory analyses showed that injections were expected to have the most rapid onset and long-lasting effects, and to be most frightening and expensive, while topical medication was expected to be the safest and the easiest to use, and oral medication was expected to have the most side effects. Higher expected effectiveness was moderately associated with expectations of more rapid onset and long-lasting effects, and better safety and ease of use. Associations of expected effectiveness with respondent characteristics (e.g. medication use and personality characteristics) were statistically small or nonsignificant.

CONCLUSIONS

Expected effectiveness of medication differed depending on route of administration and targeted symptom. These findings have important implications for the design and interpretation of clinical trials and suggest that medication effects might be enhanced by prescribing medicine via the route that patients expect to be most effective for their complaint.

SIGNIFICANCE

Differences in the expected effectiveness of medication depend on the route of administration (oral, injection, topical) and targeted symptom (pain, itch). These findings have important implications for clinical practice and the design and interpretation of clinical trials.

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

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

Nocebo Effects and Experimental Models in Visceral Pain

Despite its clinical relevance and the potential to extend insights into the processing and modulation of pain derived from investigations of placebo phenomena, the nocebo effect has received comparably little attention over the past decades. Research from experimental and clinical studies is only beginning to unravel the behavioral, functional, and psychoneurobiological mechanisms underlying the nocebo effect. Herein, we summarize current evidence regarding nocebo effects in the field of pain, with a particular emphasis on visceral pain. We provide an overview over behavioral and neuroimaging findings on the impact of expectations and learning and propose promising future directions to help fostering the transition of experimental research from bench to bedside.

Expectation of a Decrease in Pain Affects the Prognosis of Pain in Cancer Patients: a Prospective Cohort Study of Response to Morphine

Purpose

Cancer pain is a multidimensional experience that includes physiological, sensory, affective, cognitive, behavioral, and sociocultural dimensions. Few prospective studies have examined the relationship between a patient’s expectation of pain improvement and the pain prognosis. The aim of this prospective study was to investigate whether patients’ expectation to pain reduction was associated with pain intensity after morphine treatment in opioid treatment-naïve patients with various types of cancer.

Methods

The subjects were patients scheduled for cancer pain treatment with morphine who were taking nonsteroidal anti-inflammatory drugs daily. Morphine treatment was performed according to the standard method, including titration (NCCN Guidelines™, Adult Cancer Pain). Simple regression analysis was performed between pain intensity numerical rating scale (NRS) (day 8) as the dependent variable, expectation of pain decrease NRS (day 1), tumor types, and the following covariates as independent variables: patients’ characteristics such as age, gender, PS (day 1), genotype of catechol-O-methyltransferase, total scores of Hospital Anxiety and Depression Scale (day 1), and pain intensity NRS (day 1). Multiple regression analysis was performed using forced entry methods with pain intensity NRS (day 8) as the dependent variable, and expectation of pain decrease NRS (day 1) and the covariates as independent variables that had a p value <0.05 in the simple regression models.

Results

A total of 100 patients with baseline data were included, and 97 patients (51% female) met the inclusion criteria. Patients with a high expectation of pain decrease NRS had a significantly lower pain intensity NRS (day 8) (p = 0.001).

Conclusion

Non-pharmacological factors such as expectations for pain treatment could also be important factors to treat cancer pain, which might be associated with communication skills in physicians.

The Underestimated Significance of Conditioning in Placebo Hypoalgesia and Nocebo Hyperalgesia

Placebo and nocebo effects are intriguing phenomena in pain perception with important implications for clinical research and practice because they can alleviate or increase pain. According to current theoretical accounts, these effects can be shaped by verbal suggestions, social observational learning, and classical conditioning and are necessarily mediated by explicit expectation. In this review, we focus on the contribution of conditioning in the induction of placebo hypoalgesia and nocebo hyperalgesia and present accumulating evidence that conditioning independent from explicit expectation can cause these effects. Especially studies using subliminal stimulus presentation and implicit conditioning (i.e., without contingency awareness) that bypass the development of explicit expectation suggest that conditioning without explicit expectation can lead to placebo and nocebo effects in pain perception. Because only few studies have investigated clinical samples, the picture seems less clear when it comes to patient populations with chronic pain. However, conditioning appears to be a promising means to optimize treatment. In order to get a better insight into the mechanisms of placebo and nocebo effects in pain and the possible benefits of conditioning compared to explicit expectation, future studies should carefully distinguish both methods of induction.

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

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

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

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

Expectancy Reduces Symptoms but not Functional Impairment Following Exercise-induced Musculoskeletal Injury

OBJECTIVES

To quantify the extent to which the participant-provider interaction influences the response to sham treatment following exercised-induced acute musculoskeletal pain.

MATERIALS AND METHODS

In total, 40 participants between the ages of 18 and 35 volunteered for the study. Participants came to the laboratory for 3 test sessions 48-hour apart (day 1, 3, and 5). During the initial session, baseline measures were assessed and participants underwent a fatigue protocol for the biceps brachii. Participants were then assigned to a positive expectation or a no-expectation condition before receiving a sham laser therapy treatment. The positive expectation group received symptom improvement priming before their sham treatment. Participants allocated to the no-expectation condition received no feedback before the sham treatment. Maximum voluntary isometric contraction; relaxed elbow angle; visual analog scale; and the QuickDash questionnaire were used as outcome measures.

RESULTS

The positive expectation group had a significant reduction in perceived pain compared with the no-expectation group at day 3 follow-up, with the mean scores being 34.65 mm (SE=4.44) compared with 49.4 mm (SE=5.79), respectively. There were no between-group differences with respect to maximum voluntary isometric contraction, QuickDash, or relaxed elbow angle outcomes. In addition, there were no significant between-group differences observed with expected pain on follow-up visits, the effect sizes were d=0.26 on day 1 for day 3 and d=0.51 on day for day 5.

DISCUSSION

Positive expectations before a sham treatment enhanced reduction in pain intensity but did not improve functional impairments following exercise-induced acute musculoskeletal injury.

Treatment expectations but not preference affect outcome in a trial of CBT and exercise for pain

Background: Patients' beliefs and attitudes toward a treatment can affect treatment response. In unblinded trials this can affect outcomes. Aims: The aim of this analysis was to examine the association between treatment preference and expectation and outcome in a trial of pain treatments. Methods: In a randomized trial (ISRCTN67013851) of four treatments for chronic widespread pain, participants were asked which they would prefer and what improvement they expect from each. The proportion of participants reporting positive health outcomes at three time points after treatment were compared between those matched or unmatched with their preference and between those with and without expectation for improvement. Odds ratios were calculated adjusted for baseline characteristics associated with preference and expectation. Results: Four hundred forty-two participants were recruited to the trial (69.5% female). The proportion reporting positive outcomes among participants matched to their preference compared to those unmatched was 33.3% vs. 34.4% at the end of treatment (adjusted odds ratio [aOR] = 0.80, 95% confidence interval [CI], 0.44-1.46), 34.4% vs. 29.0% at 3 months (aOR = 1.23, 95% CI, 0.67-2.26), and 34.8% vs. 30.3% at 2 years (aOR = 1.31, 95% CI, 0.70-2.46). The proportion of participants reporting positive outcomes among those expecting improvement compared to those not expecting improvement was 36.6% vs. 15.0% at the end of treatment (aOR = 2.03, 95% CI, 1.07-3.85), 34.1% vs. 13.2% at 3 months (aOR = 2.31, 95% CI, 1.22-4.38), and 32.8% vs. 19.1% at 2 years (aOR = 1.16, 95% CI, 0.67-2.36). Conclusions: Treatment preference had no clear effect on outcomes, but expectation did. These results could inform future approaches to management, and researchers assessing treatments should take into account this expectation effect.