Deceptive and Nondeceptive Placebos to Reduce Pain: An Experimental Study in Healthy Individuals

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

SIGNIFICANCE

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

Choice over placebo administration enhances open-label placebo hypoalgesia

ABSTRACT

Many studies indicate that deceptively administered placebos can improve pain outcomes. However, the deception involved presents an ethical barrier to translation because it violates informed consent and patient autonomy. Open-label placebos (OLPs), inert treatments that are openly administered as placebos, have been proposed as an ethically acceptable alternative. Early studies have suggested that OLP can improve pain outcomes, but important questions remain as to how to maximise OLP hypoalgesia to improve treatment outcomes in pain patients. This study investigated whether providing choice over when to administer an OLP treatment has the capacity to enhance OLP hypoalgesia using an electrocutaneous pain paradigm. One hundred thirty-two healthy volunteers were randomised to 3 types of treatment: OLP with choice, OLP without choice, and no treatment (natural history). The OLP groups were further randomised such that half were tested with a consistent pain intensity and the other half were tested with variable pain intensity to mimic day-to-day variability in pain intensity in health settings. The results indicated that treatment provided with choice exhibited greater OLP hypoalgesia than that provided without choice and that greater expectancy mediated this effect. Of interest, there was no evidence for OLP hypoalgesia without choice relative to natural history. Furthermore, variability in pain intensity did not affect OLP hypoalgesia. The current findings present novel evidence that choice over treatment administration may be a cheap and effective strategy for boosting the efficacy of OLPs in the clinical care of pain.

If only they knew! A non-inferiority randomized controlled trial comparing deceptive and open-label placebo in healthy individuals

BACKGROUND

Placebo use is widespread in clinical practice. However, they are most often administered deceptively rather than openly. It is often suggested that open-label placebos (OLP) are less effective than deceptive placebos (DP). This study aimed to compare the use of DP and OLP treatments to reduce pain in healthy volunteers.

METHODS

We conducted a non-inferiority, parallel, randomized, controlled trial, which also included a nested cross-over no-treatment condition. This study was conducted at a university clinic in France.

RESULTS

We included 60 subjects and the main result shows that the OLP was not inferior to the DP by a margin of 10 mm. The mean difference between both groups regarding intensity of pain was 0.7 mm with a 95% compatibility interval (95% CI) of ]-∞; 5.4], and 97.5% CI of ]-∞; 6.3]. Secondary outcomes require cautious interpretation of the effect of placebo versus no treatment due to a time-treatment interaction.

CONCLUSION

The study indicates that OLP may perform just as well as DP and could provide support for the use of OLP as an ethical alternative to DP when they are to be used in a clinical setting. If only patients knew about the placebo nature of some treatments they are receiving, unnecessary lies could be avoided while maintaining similar placebo effects.

SIGNIFICANCE

This study is the first to show non-inferiority of placebos administered honestly, also called OLP, compared to DP in reducing pain. This suggests that OLP could be as effective as their deceptive counterparts while having the ethical advantage of not being required to lie. If deception is not a necessary condition for efficacy, OLP should be preferred over DP.

Development and Psychometric Evaluation of the Hope in Medicine Scale

Background

Hope is an integral, multi-dimensional part of seeking medical treatment. The aim of this study was to develop a self-report scale, the Hope in Medicine (HIM) scale, to measure different modes of hoping in relation to the course of symptoms, the effects of treatment, and supporting medical research.

Method

We examined the psychometric properties of the scale in a sample of 74 allergic rhinitis patients participating in a 2-week randomized-controlled trial comparing open-label placebos (OLP) with treatment as usual (TAU).

Results

The HIM scale had a Cronbach's α of .78. An exploratory factor analysis revealed four factors: realistic hope (i.e., hoping for specific positive outcomes such as improvement in symptoms), transcendent hope (i.e., non-directed hoping that things will turn out positively), utopian hope (i.e., hoping to contribute to greater knowledge), and technoscience hope (i.e., hoping for scientific breakthroughs). Speaking to the convergent validity of the scale, realistic hope was moderately related to treatment expectancies (r = .54); transcendent hope was related to optimism (r = .50), treatment expectancies (r = .37), self-efficacy (r = .36), and inversely correlated with pessimism (r = -.43). Hope subscales predicted neither course of symptoms nor impairment.

Conclusion

The HIM scale is a questionnaire with adequate internal consistency allowing to assess four modes of hoping. Preliminary results for its convergent validity are promising. Yet, further validation is needed.

Boosting open-label placebo effects in acute induced pain in healthy adults (BOLPAP-study): study protocol of a randomized controlled trial

Introduction

Pain is a highly prevalent symptom in the hospital setting, but treatment options remain limited. Harnessing the placebo effect in an ethical manner could provide a new possibility to reduce pain in clinical practice. So called open-label placebos (OLP) have been shown to elicit significant effects in reducing acute pain. But, before implementation, more knowledge concerning the properties of OLPs is needed. This study aims to assess the duration of analgesic effects from OLP and to determine the possibility of boosting such effects.

Methods and analysis

This is the protocol of an ongoing (first patient enrolled in March 2023) single-site randomized trial investigating OLPs in two parts (i.e., substudies). In both parts, pain will be induced in healthy adults using an intradermal electrical stimulation model. Participants in Part 1 will have two study visits: An interventional visit with one OLP injection accompanied by an evidence-based treatment rationale and a control visit with no treatment. For Part 2, participants will be randomized into three groups: (1) A fixed-time "Booster" group including one single repetition of the OLP injection at a fixed time point, (2) an on-demand "Booster" group including one single repetition of the OLP injection on-demand, and (3) a control group who will receive just one OLP injection. Differences in pain ratings over time (using the Numeric Rating Scale) will be analyzed with several two-sample t-tests. The time point for a fixed-time "Booster" in Part 2 will be derived from Part 1 with additional statistical tools such as a broken-stick mixed-effect model.

Discussion

This study aims to further characterize the analgesic effects of OLPs. In doing so, it will provide valuable information needed for later implementation of OLPs in clinical practice, where they could play a role in multimodal analgesic concepts.

Ethics and dissemination

The "Ethikkommission Nordwest- und Zentralschweiz" (BASEC 2023-00296) approved the study protocol. Results of the analysis will be submitted for publication in a peer-reviewed journal.

Clinical Trial Registration

This study is registered at ClinicalTrials.gov (NCT05819476) and is listed in the Swiss National Registry at kofam.ch (SNCTP000005470).

The role of positive information provision in open-label placebo effects

Open label placebos (OLPs) appear generally efficacious among clinical samples, but the empirical evidence regarding their use in non-clinical and sub-clinical samples, as well as when administered independent of a convincing rationale, is mixed. Healthy participants (N = 102) were randomised to either a 6-day course of OLP pills with information provision (OLP-plus: N = 35), without information provision (OLP-only: N = 35), or no-treatment control group (N = 32). OLP pills were described as enhancing physical (symptoms and sleep) and psychological (positive and negative emotional) well-being. Well-being was assessed at baseline and on Day 6. Expectancies and adherence were measured. OLP administration interacted with baseline well-being. The OLP-plus group demonstrated increased well-being on all outcomes other than positive emotions, but only when they reported decreased baseline well-being. OLP-only and control groups did not differ. The OLP-plus group demonstrated elevated expectancies, that mediated the OLP effect on physical symptoms relative to control, but only when well-being was lower than average at baseline (i.e. moderated-mediation). Results demonstrate the importance of information provided with OLPs. The moderating effect of baseline outcomes may reconcile inconsistent results regarding clinical and non-clinical samples. Accounting for baseline symptoms in non-clinical and sub-clinical samples is likely to enhance our understanding of when OLPs are effective.

The roles of expectation, comparator, administration route, and population in open-label placebo effects: a network meta-analysis

Three meta-analyses have demonstrated the clinical potential of open-label placebos (OLPs). However, there is a need to synthesize the existing evidence through more complex analyses that would make it possible to answer questions beyond mere efficacy. Such analyses would serve to improve the understanding of why and under what circumstances OLPs work (e.g., depending on induced expectations or across different control groups). To answer these questions, we conducted the first network meta-analyses in the field of OLPs. Our analyses revealed that OLPs could be beneficial in comparison to no treatment in nonclinical (12 trials; 1015 participants) and clinical populations (25 trials; 2006 participants). Positive treatment expectations were found to be important for OLPs to work. Also, OLP effects can vary depending on the comparator used. While the kind of administration route had no substantial impact on the OLP effects, effects were found to be larger in clinical populations than in nonclinical populations. These results suggest that the expectation, comparator, administration route, and population should be considered when designing and interpreting OLP studies.

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

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

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

ABSTRACT

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

Open-label placebos-a systematic review and meta-analysis of experimental studies with non-clinical samples

The use of open-label placebos (OLPs) has shown to be effective in clinical trials. We conducted a systematic review and meta-analysis to examine whether OLPs are effective in experimental studies with non-clinical populations. We searched five databases on April 15, 2021. We conducted separate analyses for self-reported and objective outcomes and examined whether the level of suggestiveness of the instructions influenced the efficacy of OLPs. Of the 3573 identified records, 20 studies comprising 1201 participants were included, of which 17 studies were eligible for meta-analysis. The studies investigated the effect of OLPs on well-being, pain, stress, arousal, wound healing, sadness, itchiness, test anxiety, and physiological recovery. We found a significant effect of OLPs for self-reported outcomes (k = 13; standardized mean difference (SMD) = 0.43; 95% CI = 0.28, 0.58; I² = 7.2%), but not for objective outcomes (k = 8; SMD =  - 0.02; 95% CI =  - 0.25, 0.21; I² = 43.6%). The level of suggestiveness of the instructions influenced the efficacy of OLPs for objective outcomes (p = 0.02), but not for self-reported outcomes. The risk of bias was moderate for most studies, and the overall quality of the evidence was rated low to very low. In conclusion, OLPs appear to be effective when examined in experimental studies. However, further research is needed to better understand the mechanisms underlying OLPs.

Open-Label Placebo Effects on Psychological and Physical Well-Being: A Conceptual Replication Study

Background

Contrary to traditional placebos, open-label placebos (OLP) abstain from deception, i.e., participants are openly informed to receive an inert substance. Studies in clinical and healthy samples evidence the efficacy of OLPs. This study aims to conceptually replicate and expand findings of a recent OLP study in healthy participants while implementing a within-subject design and daily instead of retrospective assessments. Additionally, the effect of a brand name on the medicine container is tested and possible predictors of the OLP effects are explored.

Method

Healthy participants (N = 75) received OLP and no placebo for 5 days each (randomized sequence) and answered daily questionnaires on sleep quality, bodily symptoms, mental well-being, and psychological distress. The medicine container of half the participants had a brand name, the remaining did not. Different personality traits and situational factors were assessed.

Results

Mental and physical well-being did not differ between OLP and control phase, i.e., overall, no OLP effect emerged. Contrast analysis indicated that an OLP effect emerged for sleep quality and psychological distress when no brand name was present. Further, an OLP effect emerged in persons with higher expectations for bodily symptoms (r = .23, p = .046) and psychological distress (r = .24, p = .037).

Conclusions

Methodological differences to the original study are discussed as an explanation for the failure to induce overall OLP effects. Future studies should continue to replicate previous findings and determine the exact conditions of successful implementation of OLP effects in healthy as well as clinical samples.

Deceptive and open-label placebo effects in experimentally induced guilt: a randomized controlled trial in healthy subjects

Placebos are known to yield significant effects in many conditions. We examined deceptive and open-label placebo effects on guilt, which is important for self-regulation and a symptom of mental disorders. Following an experimental induction of guilt, healthy subjects were randomized to deceptive placebo (DP; n = 35), open-label placebo (OLP; n = 35), or no treatment (NT; n = 39). The primary outcome was guilt responses assessed in area under the curve (AUC). Secondary outcomes were shame, guilt, and affect. We hypothesized that DP and OLP would reduce guilt compared to NT. Guilt responses were higher in the NT group than in the placebo groups (estimate = 2.03, 95% CI = 0.24-3.82, d = 0.53), whereas AUC guilt did not differ significantly between the placebo groups (estimate = -0.38, 95% CI = -2.52-1.76, d = -0.09). Placebos are efficacious in reducing acute guilt responses, regardless of the placebo administration (i.e., open vs. deceptive). Furthermore, we observed narrative-specific effects with significant changes of guilt but not shame, pride, or affect. These results indicate not only that guilt is amenable to placebos but also that placebos can be administered in an ethical and potentially emotion-specific manner.

Can placebos reduce intrusive memories?

After traumatic experiences, intrusive memories can flash back and evoke significant distress. Here, we investigated whether the frequency and severity of intrusions can be reduced by the provision of placebo. After the (online) exposure to the trauma-film paradigm, healthy participants (N = 112) received deceptive placebo (DP), open-label placebo (OLP), or no treatment. In the DP group, participants were led to believe to receive a dopamine-modulating drug, which was supposed to disrupt the consolidation of traumatic memories, although they in fact received the same placebo tablets as the OLP group for one week. The results show that the groups did not differ in the frequency of intrusive memories after one week. However, participants receiving OLP reported a significantly reduced intensity of intrusions as compared to DP. Across groups, negative expectations about the intensity and controllability of intrusions were associated with a higher frequency of intrusions, higher distress, higher burden, and more negative appraisal. The results suggest that expectations play an important role in the emergence of intrusive memories and that some of the disabling aspects of intrusive memories can be reduced by placebo. This may carry clinical potential because placebos are an accessible, cost-effective intervention to reduce the risk of intrusive memories.

No open-label placebo effect in insomnia? Lessons learned from an experimental trial

BACKGROUND

Open-label placebo (OLP) treatment seems to be effective in several medical conditions but has not yet been investigated in insomnia. Furthermore, it needs to be evaluated whether providing a plausible treatment rationale is essential to obtain OLP effects.

METHODS

In two consecutive nights, the sleep of patients with primary insomnia (n = 45) was assessed via subjective and objective measures. Before the second night, they received a single OLP pill that was randomly provided either with a treatment rationale (OLP+) or without (OLP-). When (M)ANOVAs did not reveal differential effects between the two OLP groups, the OLP+ group was compared post-hoc to a formerly assessed no pill control sample (NPC; n = 23).

RESULTS

Neither the MANOVAs nor the ANOVAs revealed significant interaction effects of treatment group and assessment night. The OLP+ condition was superior neither to OLP- nor to NPC in improving the patients' sleep.

DISCUSSION

Our findings do neither confirm the general efficacy of OLP in primary insomnia nor differential effects depending on the treatment rationale. Possible explanations lie in the dosing scheme (i.e., single OLP application), the provision of the OLP rationale by video and the experimental instead of therapeutic character of our investigation. Trials with larger samples and longer-term OLP treatment in insomnia are needed. Providing the rationale face-to-face and in a clinical setting might be additionally beneficial.

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.

Open-Label Placebo Treatment for Experimental Pain: A Randomized-Controlled Trial with Placebo Acupuncture and Placebo Pills

Objective: An open-label placebo (OLP) is a placebo treatment in which the patient is aware that the treatment is a placebo. OLPs are considered effective for reducing pain, and previous studies have shown a stronger placebo effect for placebo acupuncture than for placebo pills. In this study, the authors compared the analgesic effects of OLP pills, OLP acupuncture, and a no treatment condition in healthy participants, and then examined the factors contributing to the OLP effect. Design: Randomized controlled crossover trial. Settings/Location: College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea. Subjects: 34 healthy participants. Intervention: Participants received three different treatments ("OLP-pill," "OLP-acupuncture," and "no treatment") on three separate days in random order. Outcome Measurements: Before and after the treatment, heat pain stimuli were applied to the participants' hands, and pain tolerance, intensity, and unpleasantness were measured using a visual analog scale (range, 0-10). Results: Data of 31 participants were included in the analysis. The authors found significant analgesic effects of the placebo pill and placebo acupuncture in the OLP condition. Regression analyses revealed that expectations regarding treatment and practitioner identity influenced the analgesic effects of OLP acupuncture. There was no adverse event. Conclusions: Expectations regarding treatment and practitioner identity influenced the analgesic effect of placebo acupuncture without deception. These findings provide new information regarding the cognitive factors underlying pharmacologic and nonpharmacologic treatments. Clinical Trial Registration Number: KCT0004928.

Expectations: How and when do they contribute to placebo analgesia?

In placebo research, expectations are highlighted as one of the most influential subjective factors. While some studies have shown a relationship between expectations and pain relief, others have not. However, little is known about how methods of assessment of expectations may affect these conclusions. One of the fundamental considerations is that participants in placebo trials rate their expectations when prompted to rate them on scales in advance, but are less likely to report their prior expectations, when asked to report their experience retroactively in an unprompted manner, often expressing, for example, prior hope or wishes of recovery. This article presents previously unpublished data to elucidate and explore the concepts highlighted by individuals in a placebo analgesia trial when assessed in a prompted and unprompted manner. The data corroborates the role of expectations involved in placebo effects, particularly in placebo analgesia. Thus, the question may be a matter of how and when expectations contribute to placebo effects, rather than if.

How orthopedic surgeons view open label placebo pills: Ethical and effective, but opposed to personal use

OBJECTIVE

To examine attitudes of Open Label Placebos (OLP) among a national sample of US orthopedic surgeons.

METHODS

Orthopedic surgeons across the US were invited to participate in a brief online cross-sectional survey; n = 687 participated. The survey included a short vignette of a surgeon using adjunctive OLPs in addition to opioids for postoperative pain management. Participants indicated how ethical and effective they thought OLPs would be in this context, and whether they would personally consider using OLPs.

RESULTS

Nearly three-quarters (73.9%) of the surgeons considered OLPs ethical. In total, 55.4% and 48.8% of participants said that OLPs would "probably" or "definitely" be effective for Vicodin reduction and pain relief, respectively. However, only 19.2% of participants indicated they were personally willing to consider OLPs, and 59.6% were unwilling to do so.

CONCLUSIONS

Generally, orthopedic surgeons perceive OLPs as both ethical and effective, but would not consider using them in their practice. Further research is needed to identify clinician barriers to OLP use.

Open-Label Placebo Treatment for Acute Postoperative Pain (OLP-POP Study): Study Protocol of a Randomized Controlled Trial

Introduction: Open-label placebos have been proposed as way of using long recognized analgesic placebo effects in an ethical manner. Recent evidence shows efficacy of open-label placebos for clinical conditions, but there is need for more research on open-label placebos in acute pain. In the treatment of acute postoperative pain, minimization of opioid related side effects remains one of the key challenges. Therefore, this study aims at investigating the potential of adding unconditioned open-label placebos to treatment as usual as a means of reducing opioid consumption and its related side effects in patients with acute postoperative pain. Methods and Analysis: This is the protocol of an ongoing single site randomized controlled trial. The first patient was enrolled in May 2020. In total, 70 patients suffering from acute postoperative pain following dorsal lumbar interbody fusion are randomized to either a treatment as usual group or an experimental intervention group. The treatment as usual group consists of participants receiving a patient-controlled morphine pump. On day 1 and 2 post-surgery, patients in the intervention group receive, in addition to treatment as usual, two open-label placebo injections per day along with an evidence-based treatment rationale explaining the mechanisms of placebos. The primary outcome is measured by means of self-administered morphine during day 1 and 2 post-surgery. Several other outcome measures including pain intensity and adverse events as well as potential predictors of placebo response are assessed. Analysis of covariance will be used to answer the primary research question and additional statistical techniques such as generalized linear mixed models will be applied to model the temporal course of morphine consumption. Discussion: This study will provide valuable insights into the efficacy of open-label placebos in acute pain and will potentially constitute an important step toward the implementation of open-label placebos in the clinical management of acute postoperative pain. In addition, it will shed light on a cost-efficient and patient-centered strategy to reduce opioid consumption and its related side effects, without any loss in pain management efficacy. Ethics and Dissemination: The "Ethikkommission Nordwest- und Zentralschweiz" (BASEC2020-00099) approved the study protocol. Results of the analysis will be submitted for publication in a peer-reviewed journal. Clinical Trial Registration: The study is registered at ClinicalTrials.gov (NCT04339023) and is listed in the Swiss national registry at kofam.ch (SNCTP000003720).

Treating Pain With Open-Label Placebos: A Qualitative Study With Post-Surgical Pain Patients

Prior research has shown that Open Label Placebos (OLPs; that is, placebos described honestly as inactive pills) are effective for a variety of clinical conditions, including pain. However, little is known about patient attitudes towards OLPs. We conducted qualitative interviews with n = 11 patients (73% female) who recently had hand or wrist surgery and took ≥ 1 opioid pill. Interview topics included: pain management, the placebo effect, and in particular, attitudes towards OLPs. Interviews were analyzed inductively and content-coded. Five themes were identified: 1) Role of the mind in pain and illness, 2) Shortcomings of opioids are the strengths of OLPs, 3) Perceptions of OLP effectiveness, 4) Relational aspects of OLP administration, and 5) Practical considerations for OLP implementation. Most patients agreed that, because of their transparency, OLPs are ethical. Participants indicated some degree of reluctance about using OLPs, but the majority said they would take OLPs if prescribed by a doctor. Patients noted that the primary disadvantage of opioids is their potency, which can lead to addiction or side-effects; by contrast, the primary advantage of placebos is their inertness. Results suggest that OLPs appear to be well received as a postoperative pain treatment among the patients in this study. PERSPECTIVE: This qualitative study examines how hand surgery patients view OLPs, which are placebos described honestly as inactive pills. OLPs were generally well received by patients as a treatment for pain after surgery and could be considered as an adjunctive treatment to potentially reduce reliance on prescription opioids.

Providing open-label placebos remotely-A randomized controlled trial in allergic rhinitis

Background

Placebos can reduce physical symptoms even when provided with full honesty and disclosure. Yet, the precise mechanisms underlying the effects of “open-label placebos” (OLPs) have remained subject of debate. Furthermore, it is unclear whether OLPs are similarly effective when provided remotely, as is sometimes required e.g. in the current COVID-19 pandemic.

Methods

In a randomized-controlled trial, we examined the effects of OLP plus treatment as usual (TAU) compared to TAU alone on symptom reduction in people with allergic rhinitis (N = 54) over the course of two weeks. Due to the COVID-19 pandemic, OLP was provided remotely (i.e. sent via postal service). To investigate the potential influence of the clinical encounter on the effects of OLP, we manipulated the perception of the virtual clinical encounter, both with respect to verbal and nonverbal factors (augmented vs. limited encounter).

Results

The results of the manipulation check confirmed that the augmented clinical encounter was evaluated more positively than the limited encounter, in terms of perceived warmth of the provider. Participants from all treatment groups showed significant symptom reduction from baseline to two weeks later, but OLP had no incremental effect over TAU. Participants benefitted more from OLP when they did not take any other medication against allergic symptoms than when taking medication on demand. When controlling for baseline symptoms, a significant treatment by encounter interaction was found, pointing to greater symptom improvement in the OLP group when the encounter was augmented, whereas the control group improved more when the encounter was limited.

Discussion

The study demonstrates that providing OLP and enhancing the encounter remotely is possible, but their effectiveness might be lower in comparison to previous studies relying on physical patient-provider interaction. The study raises questions for future research about the potential and challenges of remote placebo studies and virtual clinical encounters. The study has been registered as a clinical trial at ISRCTN (record number: 39018).

Effects of open-label placebos on test performance and psychological well-being in healthy medical students: a randomized controlled trial

Psychological distress is prevalent in students and can predispose to psychiatric disorders. Recent findings indicate that distress might be linked to impaired cognitive performance in students. Experimental findings in healthy participants suggest that placebo interventions can improve cognition. However, whether non-deceptive (i.e., open-label, OLP) placebos can enhance cognitive function and emotional well-being is unclear. Using a randomized-controlled design we demonstrate a positive impact of OLP on subjective well-being (i.e., stress, fatigue, and confusion) after a 21-day OLP application in healthy students during midterm exams. OLP did not improve test performance, but, within the OLP group, test performance was positively correlated with measures of general belief in the benefit of medication. These results show that OLP can counteract negative effects of acute stress on psychological well-being and might improve cognitive performance if supported by positive treatment expectations. Additionally, our findings in healthy volunteers warrant further investigation in exploring the potential of OLP in reducing stress-related psychological effects in patients. The trial was preregistered at the German Clinical Trials Register on December 20, 2017 (DRKS00013557).

A comparison of open-label and deceptive placebo analgesia in a healthy sample

OBJECTIVES

A small number of studies have supported the efficacy of open-label placebos (OLPs) in reducing pain. However, research comparing the effectiveness of OLPs with deceptive placebos (DPs) is limited, and the relative impact on pain tolerance versus intensity are not yet understood. This study therefore, examined the effectiveness of a nasal placebo administered openly and deceptively on pain intensity and tolerance during a cold pressor test (CPT).

METHOD

75 healthy participants were allocated to one of three groups; OLP (n = 25), DP (n = 26) and no-treatment (NT; n = 24). A pre-test post-test design was used, with all participants completing a baseline and post-treatment CPT, following placebo administration in the treatment groups.

RESULTS

A one-way ANCOVA revealed significant differences between groups for pain intensity, with planned contrasts revealing that this effect was driven by an increase in pain intensity scores for the NT group within the post treatment CPT, which was not evident in the OLP and DP groups. There were no significant differences between groups for changes in pain tolerance.

CONCLUSION

The increase in pain intensity reported within the post-treatment CPT in the NT group was not apparent in either the OLP or DP groups, with no significant differences between OLP and DP effectiveness. These findings suggest that deception may not be necessary for effective placebo treatment and have implications for the management of pain.

Open-label placebos for menopausal hot flushes: a randomized controlled trial

This study investigated the efficacy of an open-label placebo (OLP) treatment for menopausal hot flushes. Women with at least five moderate or severe hot flushes per day were allocated to receive four weeks of OLP for twice a day or no-treatment. Intention-to-treat analyses included n = 100 women. In comparison to no-treatment, OLP reduced the log-transformed hot flush composite score (frequency × intensity) (mean difference in change: − 0.32, 95% CI [− 0.43; − 0.21], p < 0.001, Cohen’s d = 0.86), hot flush frequency (− 1.12 [− 1.81; − 0.43], p = 0.02, Cohen’s d = 0.51), and improved overall menopause-related quality of life (− 2.53 [− 4.17; − 0.89], p = 0.02, Cohen’s d = 0.49). Twelve (24%) (vs. three [6%]) patients had 50% lesser hot flushes. Problem rating of hot flushes and subdomains of quality of life did not improve. After four weeks, the OLP group was further divided via randomization to continue or discontinue the treatment. Benefits were maintained at week 8 (log-transformed score: − 0.04 [− 0.06; 0.14], p = 0.45). There was no difference between taking placebos for 8 or 4 weeks (log-transformed score: 0.04 [− 0.17; 0.25], p = 0.73). Results indicate that open-label placebos may be an effective, safe alternative for menopausal hot flushes.

Open-Label Placebo Treatment: Outcome Expectations and General Acceptance in the Lay Population

Background

Most physicians sometimes apply therapies without specific active ingredients. Although patients seem to judge such placebo treatments as acceptable under certain circumstances, deception is still an ethical problem. Open-label placebos (OLPs) might be a promising approach to solve this dilemma. This study compared general acceptance and outcome expectations of OLPs and deceptive placebos (DPs).

Methods

In an experimental online study, 814 participants read a case vignette of a person with insomnia receiving a pill. The participants were then randomly allocated into two groups, where the second part of the vignette described the pill as either a deceptive placebo (DP group) or as an open-label placebo (OLP group). The Credibility/Expectancy Questionnaire (CEQ) assessed outcome expectations after the first (pre-assessment) and the second (post-assessment) parts of the vignette. Treatment acceptance was measured at post-assessment. Data from 798 participants were analyzed by a mixed multivariate analysis of variance (MANOVA), t-tests, and post-hoc mediation analyses.

Results

The MANOVA revealed a significant group main effect and a significant time × group interaction effect. At post-assessment, outcome expectations were higher in the DP group than in the OLP group. Acceptance of the placebo treatment was also higher in the DP group than in the OLP group. Mediation analyses confirmed that higher acceptance in the DP group was mediated by higher expectations.

Conclusions

When laypersons read about placebo treatment, their outcome expectations toward DPs were higher than toward OLPs. Surprisingly, the application of DPs was rated as more acceptable than OLPs. This result might be explained by indirect effects of treatment expectations.

Electronic supplementary material

The online version of this article (10.1007/s12529-020-09933-1) contains supplementary material, which is available to authorized users.

Placebo prevents rumination: An experimental study

BACKGROUND

Rumination is a risk factor for the development and maintenance of depressive symptoms and represents an important target for the treatment of depression. In the present study, we aimed to examine whether rumination can be reduced when participants are led to believe that they would receive medication that would prevent them from ruminating.

METHODS

In healthy participants (N= 91), an initial dysphoric state was induced via mood-suggestive music and autobiographic recall. Subsequently, participants were randomly assigned to one of two groups: an experimental group that received a deceptive active placebo via intranasal application accompanied by expectancy-enhancing instructions vs. a no-treatment control group. Then, rumination was induced via a rumination-activating task. The primary outcome was current rumination; experienced sadness was considered a secondary outcome.

RESULTS

Consistent with the hypothesis, participants receiving the placebo reported a significantly lower increase in current rumination (d= 0.57) and a higher decrease in sadness (d= 0.69) after the experimental induction than the control group.

LIMITATIONS

The external validity of this study might be limited due to the highly educated student sample.

CONCLUSIONS

The results suggest that rumination processes as well as experienced sadness can be positively influenced by placebo treatment. To evaluate its clinical potential, placebo-induced expectancy effects in rumination research should be further examined, particularly with clinically depressed patients. Also, the results imply that clinicians might consider the effects of expectations on patients' rumination tendencies, for example by explicitly addressing patients' expectations about rumination, mood, and the treatment in general.