The Effect of Singular Nonverbal Behaviours of Experimenters on Pain Reports.

Introduction: Studies suggest facial expressions of caregivers may be important in placebo effects; however, this has not been systematically tested. This experiment investigated the effects of caregivers' singular positive nonverbal behaviours (NBs) on pain reports. Methods: Fifty-one males and 53 females (total of 104) participants were randomized to four groups that were displayed positive facial expressions, tone of voice, body movement, or neutral NBs of videotaped experimenters. Subjective reports of pain, stress, arousal, and cardiac activity were obtained in a pre-test, a conditioning phase, and at a post-test. Four minutes of heat pain was induced in each test, and a placebo cream was administered before the conditioning and post-test in all groups. Results: There were no differences between the NB groups in the reduced pain. Males had larger reduction in pain in the post-test, and females had lower arousal than the opposite sex. During the conditioning, females had larger reduction in pain ie, unconditioned pain response (UPR). In females, the UPR predicted the reinforced expectation ie, increase in expectations from conditioning to post-test, and fear of minor pain negatively predicted both the UPR and reinforced expectation. Discussion: Singular NBs of caregiver were weak to enhance placebo effects. Females had lower pain during conditioning, and the UPR amplitude in females was associated with positive expectations. Moreover, for females, fear of minor pain weakened the UPR and expectations of cream. Conclusion: No NB of caregivers is more effective in reducing pain. Caregivers' NBs are less effective when displayed individually. Males and females may be different in underlying mechanisms of placebo effects.

Influence of patient-clinician relationship style on acupuncture outcomes in functional dyspepsia: A multi-site randomized controlled trial in Korea.

INTRODUCTION: Research suggests that a warm and empathic "patient-centered" patient-clinician relationship produces better clinical outcomes when compared with a more neutral "disease-centered" relationship. Acupuncturists performed both styles of therapy for patients with functional dyspepsia in Korea. METHODS: The present randomized controlled trial assigned patients (n = 73) to identical acupuncture treatment with either patient-centered augmented care or disease-centered limited care. The Korean version of the Nepean Dyspepsia Index (NDI-K) was the primary outcome measure. Secondary outcome measures included Consultation And Relational Empathy (CARE) scale. RESULTS: Both groups showed improvement in NDI-K. Patient-centered augmented acupuncture produced less effective symptom improvement compared to disease-centered limited acupuncture (NDI-K sum score and frequency; P = 0.008 and P = 0.037 respectively). CARE scores were higher for the augmented versus limited group (P = 0.001), supporting the fidelity of the experimentally controlled patient/clinician relationship. There were no significant differences between the groups in any of other secondary outcomes. CONCLUSION: Patients demonstrated greater improvement following acupuncture conducted with a more neutral, "disease-centered" style of relationship. This result is counter to similar research conducted in Western countries and suggests that cultural factors can significantly shape optimum styles of acupuncture therapy. PRACTICE IMPLICATIONS: Clinicians should consider cultural differences when applying acupuncture therapy.

Brain-computer interface relieves chronic chemotherapy-induced peripheral neuropathy: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) includes negative sensations that remain a major chronic problem for cancer survivors. Previous research demonstrated that neurofeedback (a closed-loop brain-computer interface [BCI]) was effective at treating CIPN versus a waitlist control (WLC). The authors' a priori hypothesis was that BCI would be superior to placebo feedback (placebo control [PLC]) and to WLC in alleviating CIPN and that changes in brain activity would predict symptom report. METHODS: Randomization to one of three conditions occurred between November 2014 and November 2018. Breast cancer survivors no longer in treatment were assessed at baseline, at the end of 20 treatment sessions, and 1 month later. Auditory and visual rewards were given over 20 sessions based on each patient's ability to modify their own electroencephalographic signals. The Pain Quality Assessment Scale (PQAS) at the end of treatment was the primary outcome, and changes in electroencephalographic signals and 1-month data also were examined. RESULTS: The BCI and PLC groups reported significant symptom reduction. The BCI group demonstrated larger effect size differences from the WLC group than the PLC group (mean change score: BCI vs. WLC, -2.60 vs. 0.38; 95% confidence interval, -3.67, -1.46 [p = .000; effect size, 1.07]; PLC, -2.26; 95% confidence interval, -3.33, -1.19 [p = .001 vs. WLC; effect size, 0.9]). At 1 month, symptoms continued to improve only for the BCI group. Targeted brain changes at the end of treatment predicted symptoms at 1 month for the BCI group only. CONCLUSIONS: BCI is a promising treatment for CIPN and may have a longer lasting effect than placebo (nonspecific BCI), which is an important consideration for long-term symptom relief. Although scientifically interesting, the ability to separate real from placebo treatment may not be as important as understanding the placebo effects differently from effects of the intervention. PLAIN LANGUAGE SUMMARY: Chemotherapy-induced nerve pain (neuropathy) can be disabling for cancer survivors; however, the way symptoms are felt depends on how the brain interprets the signals from nerves in the body. We determined that the perception of neuropathy can be changed by working directly with the brain. Survivors in our trial played 20 sessions of a type of video game that was designed to change the way the brain processed sensation and movement. In this, our second trial, we again observed significant improvement in symptoms that lasted after the treatment was complete.

Acupuncture for Japanese Katakori (Chronic Neck Pain): A Randomized Placebo-Controlled Double-Blind Study.

Background and Objectives: Although acupuncture is listed as a beneficial treatment for neck/shoulder stiffness, which has increased with the spread of information technology, to date, evidence of its efficacy under double-blind conditions has not been shown. This study aimed to assess whether acupuncture treatment with superficial skin piercing is superior to placebo treatment. Materials and Methods: A randomized, double-blind (practitioner-patient) placebo-controlled trial was performed at a single center with four arms (ISRCTN76896018). Four hundred patients with essential neck/shoulder stiffness were randomly assigned to penetrating needle treatment (acupuncture ritual and skin penetration), skin-touch needle treatment (acupuncture ritual and skin touch), no-touch needle treatment (acupuncture ritual alone), and no-treatment control. Each of the six acupuncturists applied a needle to each of the four acupoints in the neck/shoulder of 50 patients. Results: Each of the three treatments significantly (p = 0.01) improved neck/shoulder stiffness compared with the no-treatment control immediately and 24 h after treatment. There was a significant improvement in penetrating needle treatment over no-touch needle treatment 24 h later. However, there was no significant difference between the penetrating and skin-touch and skin-touch vs. no-touch. Conclusions: All treatments that received the ritual of acupuncture were better than the no-treatment control. Only genuine acupuncture involves the specific effects of needle insertion into the body. The acupuncture ritual had a significant impact on the subjective improvement of neck/shoulder stiffness; however, improvement with ritual alone versions of placebo acupuncture was not maintained as with superficial skin piercing. Our study provides important evidence of acupuncture efficacy and information regarding inert no-touch placebo control in acupuncture research.

Quantifying and controlling the impact of regression to the mean on randomized controlled trials in epilepsy.

OBJECTIVE: Randomized controlled trials (RCTs) in epilepsy for drug treatments are plagued by high costs. One potential remedy is to reduce placebo response via better control over regression to the mean (RTM). Here, RTM represents an initial observed seizure rate higher than the long-term average, which gradually settles closer to the average, resulting in apparent response to treatment. This study used simulation to clarify the relationship between eligibility criteria and RTM. METHODS: Using a statistically realistic seizure diary simulator, the impact of RTM on placebo response and trial efficacy was explored by varying eligibility criteria for a traditional treatment phase II/III RCT for drug-resistant epilepsy. RESULTS: When the baseline period was included in the eligibility criteria, increasingly larger fractions of RTM were observed (25%-47% vs. 23%-25%). Higher fractions of RTM corresponded with higher expected placebo responses (50% responder rate [RR50]: 2%-9% vs. 0%-8%) and lower statistical efficacy (RR50: 47%-67% vs. 47%-81%). The exclusion of baseline from eligibility criteria was shown to decrease the number of patients needed by roughly 30%. SIGNIFICANCE: The manipulation of eligibility criteria for RCTs has a predictable and important impact on RTM, and therefore on placebo response; the difference between drug and placebo was more easily detected. This in turn impacts trial efficacy and therefore cost. This study found dramatic improvements in efficacy and cost when baseline was not included in eligibility.

Brain-to-brain mechanisms underlying pain empathy and social modulation of pain in the patient-clinician interaction.

Social interactions such as the patient-clinician encounter can influence pain, but the underlying dynamic interbrain processes are unclear. Here, we investigated the dynamic brain processes supporting social modulation of pain by assessing simultaneous brain activity (fMRI hyperscanning) from chronic pain patients and clinicians during video-based live interaction. Patients received painful and nonpainful pressure stimuli either with a supportive clinician present (Dyadic) or in isolation (Solo). In half of the dyads, clinicians performed a clinical consultation and intake with the patient prior to hyperscanning (Clinical Interaction), which increased self-reported therapeutic alliance. For the other half, patient-clinician hyperscanning was completed without prior clinical interaction (No Interaction). Patients reported lower pain intensity in the Dyadic, relative to the Solo, condition. In Clinical Interaction dyads relative to No Interaction, patients evaluated their clinicians as better able to understand their pain, and clinicians were more accurate when estimating patients' pain levels. In Clinical Interaction dyads, compared to No Interaction, patients showed stronger activation of the dorsolateral and ventrolateral prefrontal cortex (dlPFC and vlPFC) and primary (S1) and secondary (S2) somatosensory areas (Dyadic-Solo contrast), and clinicians showed increased dynamic dlPFC concordance with patients' S2 activity during pain. Furthermore, the strength of S2-dlPFC concordance was positively correlated with self-reported therapeutic alliance. These findings support that empathy and supportive care can reduce pain intensity and shed light on the brain processes underpinning social modulation of pain in patient-clinician interactions. Our findings further suggest that clinicians' dlPFC concordance with patients' somatosensory processing during pain can be boosted by increasing therapeutic alliance.

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

OBJECTIVE: Placebo responses are significantly higher in children than in adults, suggesting a potential underused treatment option in pediatric care. To facilitate the clinical translation of these beneficial effects, we explored physicians' current practice, opinions, knowledge, and likelihood of recommending placebos in the future. METHODS: A cross-sectional web-based survey administered by REDCap was conducted at Boston Children's Hospital between October 2021 and March 2022. Physicians (n = 1157) were invited to participate through an email containing a link to a 23-item survey designed to assess physicians' attitudes and perceptions towards the clinical use of placebo in pediatrics. RESULTS: From 207 (18%) returned surveys, 109 (9%) were fully completed. Most respondents (79%) believed that enhancing the therapeutic components that contribute to the placebo response may be a way of improving pediatric care. However, whereas most (62%) found placebo treatments permissible, only one-third reported recommending them. In pediatrics, placebos are typically introduced as a medicine that "might help" (43%). The most common treatments recommended to enhance placebo effects are physical therapy, vitamins, and over-the-counter analgesics. Physicians most frequently recommend placebos for occasional pain, headaches, and anxiety disorders. Finally, the great majority of physicians (87%) stated they would be more likely to recommend placebo treatments if there were safety and ethical guidelines for open-label placebos. CONCLUSIONS: Placebo treatments seem permissible to physicians in pediatric care, but the development of safety and ethical guidelines may be necessary before physicians systematically incorporate the benefits of the placebo effect in pediatrics.

Effectiveness of Conditioned Open-label Placebo With Methadone in Treatment of Opioid Use Disorder: A Randomized Clinical Trial.

Importance: Methadone treatment is the most effective evidence-based treatment for opioid use disorder (OUD), but challenges related to dosing and premature treatment dropout argue for adjunct interventions to improve outcomes. One potential behavioral intervention with low risk involves harnessing placebo effects. Objective: To determine the effect of a pharmacologically conditioned open-label placebo (C-OLP) on 90-day methadone dose, retention, drug use, withdrawal, craving, quality of life, and sleep. Design, Setting, and Participants: This 2-arm, open-label, single-blind randomized clinical trial was conducted between December 5, 2017, and August 2, 2019, in an academically affiliated community opioid treatment program. Analyses were conducted between October 1, 2019, and April 30, 2020. A total of 320 newly enrolled adults seeking treatment for moderate to severe OUD were assessed for study eligibility; 131 met eligibility criteria, provided informed consent, and were randomized to either C-OLP or treatment as usual (TAU) in an unequal-block (3:2) manner. Exclusion criteria were pregnancy, hospital/program transfers, and court-ordered treatment. Interventions: Participants randomized to C-OLP received pharmacologic conditioning and a placebo pill and methadone, and participants randomized to TAU were given methadone only. Participants met with the study team 5 times: at baseline (treatment intake) and 2, 4, 8, and 12 weeks postbaseline. Interactions were balanced between the 2 groups. Main Outcomes and Measures: Outcomes included 90-day methadone dose (primary) and treatment retention, drug use, withdrawal, craving, quality of life, and sleep quality (secondary). Analyses were conducted as intention-to-treat. Results: Of the 131 people enrolled in the study, 54 were randomized to TAU and 77 to C-OLP. Mean (SD) age was 45.9 (11.2) years; most of the participants were Black or African American (83 [63.4%]) and male (84 [64.1%]). No significant group differences were observed in the mean (SD) 90-day methadone dose (83.1 [25.1] mg for group TAU, 79.4 [19.6] mg for group C-OLP; t = 0.621991; P = .43), but the groups differed significantly in their retention rates: 33 (61.1%) for TAU and 60 (77.9%) for C-OLP (χ21 = 4.356; P = .04; number needed to treat for the beneficial outcome of 3-month treatment retention, 6; 95% CI, 4-119). C-OLP participants also reported significantly better sleep quality. Conclusions and Relevance: In this randomized clinical trial, C-OLP had no effect on the primary outcome of 90-day methadone dose. However, C-OLP participants were significantly more likely to remain in treatment. These findings support the use of C-OLP as a methadone treatment adjunct, but larger trials are needed to further examine the use of C-OLP. Trial Registration: ClinicalTrials.gov Identifier: NCT02941809.

Do Placebos Primarily Affect Subjective as Opposed to Objective Measures? A Meta-Analysis of Placebo Responses in Insomnia RCTs.

INTRODUCTION: Little is known about the relative magnitude of placebo responses on objective and subjective measures of sleep continuity. To address this issue, the pre-post effects of placebos on objective and subjective measures (i.e., polysomnography [PSG] and sleep diaries) were evaluated meta-analytically. The guiding hypothesis was that large responses would be observed on sleep diary measures and small responses would be observed on PSG measures. METHODS: PubMed searches, 1967-2016, yielded 329 possible articles, 17 of which met the inclusion and exclusion criteria for the present analysis (including 879 subjects with PSG data, 1,209 subjects with diary data, and six studies with both PSG and sleep diary data). Average change and weighted effect sizes (ESs) were computed via modeling for sleep latency (SL), wake after sleep onset (WASO) and total sleep time (TST). RESULTS: Pre-to-post change on PSG measures were: SL -13.7 min., ES = -0.37; WASO -14.3 min., ES = -0.36; and TST 29.8 min., ES = 0.50. Pre-to-post change on sleep diary measures were: SL -13.5 min., ES = -0.36; WASO -13.3 min., ES = -0.20; and TST 25.5 min., ES = 0.36. The modeled average objective subjective difference per sleep continuity measure was less than 5 minutes. The modeled average objective subjective difference per sleep continuity measure (in effect sizes) was less than 0.17. DISCUSSION: The observed outcomes of this analysis suggest that placebos produce comparable effects on objective and subjective measures of sleep continuity. Thus, objective measures do not appear to protect against placebo responses. This being the case and given the importance of the subjective experience of illness severity and recovery, such data suggests that prospectively sampled sleep continuity data (sleep diaries) may be the optimal data for clinical trials, particularly when only one measure is possible.

Doctors Speak: A Qualitative Study of Physicians' Prescribing of Antidepressants in Functional Bowel Disorders.

Tricyclic antidepressants (TCAs) are frequently prescribed for chronic functional pain disorders. Although the mechanism of action targets pain perception, treating patients with TCAs for disorders conceptualized as "functional" can promote stigmatization in these patients because it hints at psychological dimensions of the disorder. The goal of this study was to understand how physicians prescribe TCAs in the face of this challenge. We interviewed eleven gastroenterologists in tertiary care clinics specializing in functional gastrointestinal disorders, such as irritable bowel syndrome. We found that the physicians interviewed (1) were aware of the stigma attached to taking antidepressants for a medical condition, (2) emphasized biological, as opposed to psychological, mechanisms of action, (3) while focusing on biological mechanisms, they nevertheless prescribed TCAs in a way that is highly attentive to the psychology of expectations, making specific efforts to adjust patients' expectations to be realistic and to reframe information that would be discouraging and (4) asked patients to persist in taking TCAs despite common and, at times, uncomfortable side effects. In this context of shared decision making, physicians described nuanced understanding and behaviours necessary for treating the complexity of functional disorders and emphasized the importance of a strong patient-provider relationship.

Women's Experience of Living with Vulvodynia Pain: Why They Participated in a Randomized Controlled Trial of Acupuncture.

Introduction: Vulvodynia is vulvar pain lasting at least 3-months without clear identifiable cause that may have other associated factors. The aim, to explore motivations of women participating in a double-blind randomized controlled trial of acupuncture for vulvodynia. Methods: Responses to the question: "Tell me about why you decided to participate in this study" were analyzed using conceptual content analysis to identify patterns in motivation for study participation. Results: Four patterns emerged: 1) desire to address uncontrolled pain, 2) desire for understanding, 3) wish to contribute to knowledge generation, and 4) need to remove cost barriers. Conclusion: Motivations indicate vulvodynia-specific aspects of acceptability of acupuncture. Clinical Trial Registration: NCT03364127.

"Let's see what happens:"-Women's experiences of open-label placebo treatment for menopausal hot flushes in a randomized controlled trial.

Open-label (honestly prescribed) placebos are an ethical way to evoke placebo effects in patients. As part of a mixed-methods study, we conducted in-depth interviews with eight menopausal women who underwent and benefitted from open-label placebo treatment in a randomized-controlled trial of hot flushes. Data were analyzed using Interpretative Phenomenological Analysis. We found that the women had low expectations about the placebo treatment yet endorsed what they referred to as "hope" and openness to "see what happens". Recording hot flushes via the symptom diary was viewed as a valuable opportunity for self-examination and appraising outcomes. Receiving relief from the placebo treatment empowered women and enhanced their sense of control and agency. In summary, participants' initial openness towards placebos, their hopes to get better, monitoring symptoms closely, and taking the initiative to address symptoms were components of a positive open-label placebo experience.

Protocol for double-blind RCT of acupuncture for vulvodynia.

Background: Vulvodynia, vulvar pain of unknown origin lasting at least 3 months, affects 7% of American women. Dyspareunia, its frequent companion, renders sexual intercourse virtually impossible. Although few therapies are efficacious and rapid pain relief is rarely possible, there have been no sham/placebo-controlled studies of acupuncture for vulvodynia. Aims are to: 1) determine efficacy of acupuncture for vulvodynia, 2) explore duration of the acupuncture effect. Methods: In a pretest/posttest randomized controlled, double-blind (practitioner-patient) efficacy trial of a standardized acupuncture protocol, we will randomize 80 participants 1:1 to either penetrating needle or skin-touch placebo needle groups. Both types of needles are designed to blind both the acupuncturist and participant. Participants with vulvodynia will insert and remove a tampon as a standardized stimulus and complete primary measures of vulvar pain (pain intensity) and secondary measures of dyspareunia (Female Sexual Function Index, FSFI dyspareunia subscale score) and sexual function (FSFI total score) pretreatment, after the 10th acupuncture session, and pain measures weekly until return to pretest levels. Upon study completion control group participants will be offered 10 free real acupuncture sessions. Discussion: This is the first multi-needle multi-session RCT using double-blind acupuncture needles as a reliable sham. We hypothesize that controlling for baseline, at posttest there will be statistically significant less vulvar pain and dyspareunia and more sexual function over five weeks in the penetrating needle group compared to the skin touch placebo group. Conclusion: This study is responsive to the need for efficacious pain management for women with vulvodynia.ClinicalTrials.gov Identifier: NCT03364127.

Skin Temperature of Acupoints in Health and Disease: A Systematic Review.

Introduction: Despite substantial progress made in the field of acupuncture research, the existence and specificity of acupoints remain controversial. In recent years, the concept of acupoint sensitization has emerged as a theoretical framework for understanding acupoints as dynamic functional entities that are sensitized in pathological conditions. Based on this premise, some have claimed that specific acupoints are thermally distinct between healthy and clinical populations, but no systematic review has been conducted to synthesize and evaluate the quality of studies supporting such claims. In this review, we provide a summary and quality assessment of the existing literature addressing the question of whether changes in skin temperature at specific acupoints are indicative of pathological conditions. Methods: A systematic literature search was performed in PubMed, EMBASE, and AltHealthWatch (EBSCO Host), by combining variations of search terms relevant to acupoints and temperature. The search was limited to the English language, and publication dates ranged from database inception to December 2020. Two authors independently screened all resulting abstracts and subsequently read full-text articles for eligibility. Information on study design, sample, acupoints, parameters of skin temperature assessments, and main findings were extracted from included studies. Quality of the thermal sensing methodology was evaluated using a thermal assessment checklist, adapted from the Thermographic Imaging in Sports and Exercise Medicine (TISEM) consensus checklist, and a modified Newcastle-Ottawa Scale (NOS) for case-control studies. Results: The search strategy yielded a total of 1771 studies, of which 10 articles met the eligibility criteria. Eight studies compared skin temperature at acupoints in healthy versus clinical populations, and two studies assessed within-subject changes in temperature of acupoints in relation to changes in health status. There were seven clinical conditions examined in the included studies: chronic bronchial asthma, chronic hepatitis, hyperplasia of mammary glands, infertility, intracranial hypertension, obesity, and primary dysmenorrhea. There were numerous methodological quality issues related to skin temperature measurements. Eight studies with case-control designs reported significant differences between healthy and clinical populations in temperature at certain acupoints. Two studies with pre-post designs reported that changes in health-disease status could be associated with changes in temperature at specific acupoints. Conclusion: A review of the available literature suggests that certain acupoints may be thermally distinct between healthy and unhealthy states. However, given the methodological limitations and heterogeneity across included studies, no definitive conclusion could be drawn as to whether changes in skin temperature at specific acupoints are indicative of pathological conditions.

Genotypes of Pain and Analgesia in a Randomized Trial of Irritable Bowel Syndrome.

Background: Irritable bowel syndrome (IBS) is a highly prevalent chronic pain disorder with multiple underlying mechanisms and few treatments that have been demonstrated to be effective in placebo controlled trials. One potential reason may be the use of composite outcomes, such as the IBS Symptom Severity Scale (IBS-SSS) which includes descriptive items related to pain frequency and pain intensity as well as bowel dysfunction and bloating. We investigated if different features of IBS pain have distinct genetic associations and if these may be moderated by sex hormones. Participants and Setting: Adult outpatients with moderately severe IBS (>175 on IBS-SSS) enrolled in a clinical trial reported IBS-SSS at baseline and after 6 weeks of therapy. Methods: Fixed effects modeling was used to test the effect of COMT rs4680 genotype to change in pain severity (rated 0-100) and pain frequency (defined as number of days with pain in the past 10 days) from baseline to week 6 with IBS treatment. Parallel exploratory genome-wide association studies (GWAS) were also performed to identify single nucleotide polymorphisms (SNPs) associated with change in pain severity or pain frequency across all participants. Results: A total of 212 participants (74% female) were included. The COMT rs4680 met allele was associated with decreased pain severity over the course of the trial in gene dosage models [beta(SE) -5.9 (2.6), P = 0.028]. Exploratory GWAS for change in pain frequency identified 5 SNPs in close proximity on chromosome 18 near L3MBTL4 which reached genome-wide significance (all P < 5.0E-8). This effect was not mediated by changing estradiol levels. There was also a region of chromosome 7 with 24 SNPs of genome-wide suggestive significance for change in pain severity (all P < 1.0E-5). Conclusions: Previously reported association between COMT rs4680 genotype and treatment response as measured by IBS-SSS is related to pain severity, but not pain frequency. We also identified new candidate genes associated with changes in IBS pain severity (SNX13) and pain frequency (L3MBTL4) in response to treatment. Further studies are needed to understand these associations and genetic determinants of different components of IBS-SSS. ClinicalTrials.gov, Identifier: NCT0280224.

Psychological Predictors of Response to Open-Label Versus Double-Blind Placebo in a Randomized Controlled Trial in Irritable Bowel Syndrome.

OBJECTIVE: There is growing evidence that open-label placebo (OLP) may be an efficacious treatment of chronic and functional conditions. However, patient-level predictors of response to OLP have not been clearly identified. The aim of this study is to evaluate the psychological predictors of response to OLP and to compare this to double-blind placebo (DBP) and no-pill control (NPC). METHODS: This study is a secondary analysis of data collected in a 6-week randomized controlled trial evaluating placebo effects in irritable bowel syndrome (IBS). The primary outcome was change in IBS severity. Hierarchical linear regression identified predictors of placebo response in general and compared them between those randomized to OLP, DBP, and NPC. Predictor variables included personality traits, generalized anxiety, depression, visceral sensitivity (a measure of symptom-specific anxiety), and pain catastrophizing. RESULTS: A total of 210 participants (mean age = 42.3 years, 73.3% female) were included. Regression models revealed that visceral sensitivity was a predictor of response to OLP and NPC but not DBP. Interestingly, the effects were opposite, with high visceral sensitivity predicting less improvement in NPC and more improvement in OLP. Pain catastrophizing was a negative predictor of response to OLP (i.e., high pain catastrophizing was associated with less improvement in OLP). Neither visceral sensitivity nor pain catastrophizing played a significant role for response to DBP. CONCLUSIONS: IBS participants who score low on the Pain Catastrophizing Scale but high on the Visceral Sensitivity Index seem to benefit particularly from OLP. Our study suggests that different psychological mechanisms may be involved in DBP and OLP interventions.

Are They Side Effects? Extraintestinal Symptoms Reported During Clinical Trials of Irritable Bowel Syndrome May Be More Severe at Baseline.

BACKGROUND & AIMS: Many of the reported adverse events in clinical trials of irritable bowel syndrome are extraintestinal symptoms, which typically are assessed by open-ended questions during the trial and not at baseline. This may lead to misattribution of some pre-existing symptoms as side effects to the treatment. METHODS: The current study analyzed data from a 6-week clinical trial of irritable bowel syndrome. Participants were randomized to receive double-blind peppermint oil, double-blind placebo, or treatment as usual. Extraintestinal symptoms were assessed at baseline and at the end of the study. RESULTS: This analysis included 173 participants (30 received double-blind peppermint oil, 72 received treatment as usual, and 71 received double-blind placebo). At baseline, each group reported approximately 5 extraintestinal symptoms per participant. The number of symptoms per participant decreased to an average of 3 by the end-of-study visit, and this change was statistically significant in all groups (P < .001 for each group). When evaluating individual extraintestinal symptoms, the majority of participants did not report new/worse symptoms. In fact, between the baseline assessment and the final assessment, the average symptom severity decreased significantly in all 3 groups (P < .001). CONCLUSIONS: Our study suggests that participants with irritable bowel syndrome often experience extraintestinal symptoms at baseline and that these symptoms generally improve in severity over the course of a clinical trial, regardless of the treatment arm. Systematic assessment of extraintestinal symptoms at the beginning of a clinical trial is necessary to determine more definitively whether these symptoms may be considered an adverse event attributable to a study medication.

Patients' experiences treated with open-label placebo versus double-blind placebo: a mixed methods qualitative study.

BACKGROUND: There is increasing evidence suggesting that open-label placebo (OLP) is an effective treatment for several medical conditions defined by self-report. However, little is known about patients' experiences with OLP, and no studies have directly compared patients' experiences in double-blind placebo (DBP) conditions. METHODS: This study was nested in a large randomized-controlled trial comparing the effects of OLP and DBP treatments in individuals with irritable bowel syndrome (IBS). We randomly selected 33 participants for interviews concerning their experiences in the parent trial. The data were qualitatively analyzed using an iterative immersion/crystallization approach. We then compared the qualitative interview data to the quantitative IBS severity data assessed during the parent trial, using a mixed methods approach. RESULTS: Two prominent interview themes were identified: (1) the participants' feelings about their treatment allocation and (2) their reflections about the treatment. Both OLP and DBP participants mentioned hope and curiosity as major feelings driving them to engage with their treatment. However, while DBP participants tended to be more enthusiastic about their allocation, OLP participants were more ambivalent. Furthermore, OLP participants reflected more on their treatment, often involving noticeable cognitive and emotional processes of self-reflection. They offered a variety of explanations for their symptom improvement and were significantly less likely to attribute it to the treatment itself than DBP participants (Χ2 [3] = 8.28; p = .041). Similarly, the participants' retrospective narratives of symptom improvement were significantly correlated with their corresponding quantitative IBS severity scores only in DBP (p's ≤ .006) but not in OLP (p's ≥ .637). CONCLUSION: OLP and DBP participants share feelings of hope, uncertainty and curiosity but differ in the extent of conscious reflection. The counter-intuitive OLP prompts more self-examination, ambivalent feelings and active engagement compared to DBP. At the same time, OLP participants are more reluctant to attribute symptom improvement to their treatment. Our findings substantially add to the emerging picture of factors that distinguish OLP and DBP and their potential mechanisms.

Patient-clinician brain concordance underlies causal dynamics in nonverbal communication and negative affective expressivity.

Patient-clinician concordance in behavior and brain activity has been proposed as a potential key mediator of mutual empathy and clinical rapport in the therapeutic encounter. However, the specific elements of patient-clinician communication that may support brain-to-brain concordance and therapeutic alliance are unknown. Here, we investigated how pain-related, directional facial communication between patients and clinicians is associated with brain-to-brain concordance. Patient-clinician dyads interacted in a pain-treatment context, during synchronous assessment of brain activity (fMRI hyperscanning) and online video transfer, enabling face-to-face social interaction. In-scanner videos were used for automated individual facial action unit (AU) time-series extraction. First, an interpretable machine-learning classifier of patients' facial expressions, from an independent fMRI experiment, significantly distinguished moderately painful leg pressure from innocuous pressure stimuli. Next, we estimated neural-network causality of patient-to-clinician directional information flow of facial expressions during clinician-initiated treatment of patients' evoked pain. We identified a leader-follower relationship in which patients predominantly led the facial communication while clinicians responded to patients' expressions. Finally, analyses of dynamic brain-to-brain concordance showed that patients' mid/posterior insular concordance with the clinicians' anterior insula cortex, a region identified in previously published data from this study1, was associated with therapeutic alliance, and self-reported and objective (patient-to-clinician-directed causal influence) markers of negative-affect expressivity. These results suggest a role of patient-clinician concordance of the insula, a social-mirroring and salience-processing brain node, in mediating directional dynamics of pain-directed facial communication during therapeutic encounters.